# Frequent regens with surging at idle



## BodhiBenz1987 (Jan 13, 2018)

My Cruze has been awesome in its first 10k miles but lately has developed some weird behavior. In the last 700 or so miles its done five regens, or what I assume are regens. In each case when I come to a stop at a light or elsewhere the idle surges very noticeably. This always coincides with the fan running after I shut it off, and decreased mpg, hence I assume the regens. The rest of the time idle is normal. I never experienced the surging once during the first 10k miles; only noticed the fan running after shutdown a couple times. There are no codes and everything else about driving feels totally normal. Is this possibly just happening because I've been doing more short drives with stoplights, combined with winter cold and winter fuel? I'm still getting just under 45 mpg for mostly local short trips and 60+ when on the highway. Has anyone else had this happen? I tried taking some advice from searches here and keeping the rpms up under load during the last time I felt the regen "symptoms" but 100 miles later, it just did another one. Do I need to take it in for a manual regen? Or just keep trying to drive it a little harder and do some highway runs? Would a fuel additive help at all?


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## Rivergoer (Mar 30, 2017)

Regens do happen much more frequently with city driving vs highway. Without an OBDII device to monitor, there’s no way to be absolutely certain when a regen starts and ends.

Once initiated, a typical regen cycle will last about 10-15 miles of driving at or above 35 mph. In city driving, the regen will take longer especially if you’re doing a lot of stopping for signals. 

If you park the car and interrupt a regen, it will take several miles on the next drive to get the engine up to operating temp and then another mile or two for the EGT to reach 1100 degrees in order to trigger DPF regen.

If the car isn’t displaying any warnings or CELs things are probably normal, no need to bring to the dealer for a forced regen. Rather than experiencing 5 different regens, it’s more likely you’ve interrupted a couple of regens multiple times and it’s restarting multiple times to complete a single cycle.

Take your diesel out on the highway for 20-30 minute drives, it’ll love you for it.


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## MRO1791 (Sep 2, 2016)

Concur with Rivergoer. Take it on a 30-45 minute highway drive and it should be fine. It sounds like several interrupted regen events. It won't throw an error code until there is some extensive soot build up in the DPF. 

Sent from my Moto G (5) Plus using Tapatalk


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## BodhiBenz1987 (Jan 13, 2018)

Thanks guys. Will try to take it on a little road trip soon. I used to be on the highway a lot more over the summer but lately have just been stuck with a lot of annoying local drives. Maybe a good excuse for a cool day trip.


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## BodhiBenz1987 (Jan 13, 2018)

So I finally got a Scangauge II hooked up and working and it confirms what I could feel anyway. The SG tells me 147 miles average between regens; 45 miles since the last one; 68% soot level already in 45 miles (all highway miles). I wish I knew why it was doing this. I do a fair amount of highway driving and have made a point of doing a little extra to help it out. Even with no CEL, the regens are noticeable and at that rate affecting my mpg, plus I imagine will eventually cause issues. I thought maybe the frequent regens had to do with a turbo failure I had at the beginning of the year, but that is repaired and the dealer did a manual regen following it, and the behavior hasn't changed.
Guess I will watch a while and see. Does any one know at what soot % a regen is triggered?


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## Rivergoer (Mar 30, 2017)

On the Gen 1, Scan Gauge measures Soot Mass (STM) in grams. 

Regen threshold is 20 gms. 

For the Gen 2 did they change STM to a percentage?


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## BodhiBenz1987 (Jan 13, 2018)

Rivergoer said:


> On the Gen 1, Scan Gauge measures Soot Mass (STM) in grams.
> 
> Regen threshold is 20 gms.
> 
> For the Gen 2 did they change STM to a percentage?


The Gen 2 does not have its own X Gauges, and the Cruze STM gauge does not seem to work for the Gen 2. I used the Colorado gauge for soot %, which I had read works on the Gen 2 Cruze, and that one reads in percentage. Maybe I can find a soot mass measure that works on the Gen 2 in grams.


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## IndyDiesel (May 24, 2015)

When I had gen 1 diesel, sometimes mine would regen at 100 miles and I had once it was over 1000 miles, I couldn’t really understand why there was a variation, I am guessing weather and fuel, summer vs winter, driving patterns, etc


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## BodhiBenz1987 (Jan 13, 2018)

For the heck of it I just took the car on a 50-mile highway drive, mostly at 70 mph, tried to keep it lively but legal. Soot % went from 68 to 92. It only dropped in the 2 miles once I got _off_ the highway at the end, back to 90. I'm assuming it triggers a regen at 100% so I'll have to see if it does that tomorrow. Something just feels off with the car and has on and off since the beginning of winter ... sometimes it feels perfect and others it feels like the power band is off. I thought it was because of the turbo but I'm starting to think that was a symptom and not the cause ... but nothing I can really do until the next CEL.


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## BodhiBenz1987 (Jan 13, 2018)

IndyDiesel said:


> When I had gen 1 diesel, sometimes mine would regen at 100 miles and I had once it was over 1000 miles, I couldn’t really understand why there was a variation, I am guessing weather and fuel, summer vs winter, driving patterns, etc


Maybe it just really hates winter fuel and colder weather, but mine still seems to be on the extreme side of frequent for not living in a terribly extreme climate or doing a lot of urban driving. Should be getting warmer out soon so that might tell me something. The car was super all last summer and fall.


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## Rivergoer (Mar 30, 2017)

After your regen today, post what % it reads right after regen completes. One would assume zero % but not necessarily.

On the Gen 1 STM after regen drops from 20 down to 3-4 grams.

Your 147 mile avg regen cycle seems abnormal. Are you driving strictly City all the time?

My worst interval dipped into the high 300’s (miles), average interval was 750 miles with mix of 75% highway/25% city. The low was nearly all city driving.


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## BodhiBenz1987 (Jan 13, 2018)

Rivergoer said:


> After your regen today, post what % it reads right after regen completes. One would assume zero % but not necessarily.
> 
> On the Gen 1 STM after regen drops from 20 down to 3-4 grams.
> 
> ...


I am driving more than 50% highway and sometimes more than that. Even the "city" I do is more suburban and not that bad. Since I started noticing the frequent regens I made a point of taking it out on a few extra highway trips since I figured I wasn't doing quite as many as I had all summer, but it didn't seem to help. It seems to be building a ton of soot under ideal highway conditions if yesterday is any indication. I am fairly certain the dealership did a manual Regen less than 1,000 miles ago as well, which would mean I started back at 0% or close. Since then I have certainly done mostly highway.


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## MRO1791 (Sep 2, 2016)

BodhiBenz1987 said:


> I am driving more than 50% highway and sometimes more than that. Even the "city" I do is more suburban and not that bad. Since I started noticing the frequent regens I made a point of taking it out on a few extra highway trips since I figured I wasn't doing quite as many as I had all summer, but it didn't seem to help. It seems to be building a ton of soot under ideal highway conditions if yesterday is any indication. I am fairly certain the dealership did a manual Regen less than 1,000 miles ago as well, which would mean I started back at 0% or close. Since then I have certainly done mostly highway.


If I had to take a guess, you have a stuck open, or sticking EGR valve. Excess EGR will cause excessive soot. How's your DEF usage? More EGR means less DEF needed. To minimize NOx the EGR puts O2 deficient air into the cylinder, which has the side effect of more soot. Less EGR would mean more DEF to take care of NOx as an after treatment. 

I have seen much more frequent regens in my manual Cruze than either of the 9sp auto Gen 2 diesels. That is interesting. The manual has 30 regens in 13k miles, the auto has 18 with about 12.5 k miles. 

Another possibilty for the difference, it's possible to run lower RPM in town with the manual. Lower RPM under load would tend to generate more soot. The auto won't let you do that, so it seems to be more efficient at minimizing soot. 

All that said, my manual is over 400 miles average regen, auto about 700 miles. Your interval is not normal. 

Sent from my Moto G (4) using Tapatalk


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> BodhiBenz1987 said:
> 
> 
> > I am driving more than 50% highway and sometimes more than that. Even the "city" I do is more suburban and not that bad. Since I started noticing the frequent regens I made a point of taking it out on a few extra highway trips since I figured I wasn't doing quite as many as I had all summer, but it didn't seem to help. It seems to be building a ton of soot under ideal highway conditions if yesterday is any indication. I am fairly certain the dealership did a manual Regen less than 1,000 miles ago as well, which would mean I started back at 0% or close. Since then I have certainly done mostly highway.
> ...


I'd find it hard to believe that the car could go through a whole turbo replacement atth dealer and have them not notice a stuck EGR, but maybe the turbo issue masked it. It had two codes due to the turbo and one of them was EGR related, but did go away with the new turbo. Is there any way to tell if the valve is sticking with no engine light? Aside from DEF which I'll try to make note of. I haven't noticed anything crazy. I'll top off soon so I can keep better track ... They topped off at the dealer but I'm not sure with how much.
I had wondered that about low rpms. I wonder if I lug the car too much because you can so easily get away with it in these cars (maybe I don't even notice). Even then that wouldn't explain why the soot is still rising rapidly on highway only where driver-input isn't really a factor.


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## BodhiBenz1987 (Jan 13, 2018)

Update from today: It did indeed go into a regen. My regen status gauge didn't work but maybe I entered it wrong. The EGR temps went way up and the soot level % dropped from 100 to 2. Once it got to 2 the EGR temps started dropping and the "since last" gauge went to 0. From 117 ... so it only took 117 miles of probably 80% highway to build up that much soot. In the 4 miles since the regen it went from 2 to 15 % soot level. 
None of the other gauges jump out to me as suspicious, but if there are any parameters anyone can think of that might give a clue, please chime in. I think given the conditions before, during, and after the last two regens I can't blame this on driving conditions or my own driving habits.
I am going to check the air filter this afternoon, though I'm pretty sure they did that during the last oil change.


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## Rivergoer (Mar 30, 2017)

I wonder if the bad turbo sent oil into the DPF?


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## BodhiBenz1987 (Jan 13, 2018)

Rivergoer said:


> I wonder if the bad turbo sent oil into the DPF?


Possible. Maybe that would cause the DPF to think there's more soot than there is?

I'm wondering at this point if I should just take it to the dealer. My hesitation is that I don't think they will want to do anything without a code or obvious sign something is wrong ... i.e., they probably do not want to hear what I learned from my amateur gauge. On the other hand this was something I observed for quite a while without the gauge and would continue to notice gauge or not, and might be relevant to a documented previous failure, so maybe it makes sense to bring it up ASAP? My other alternative is to wait until something major fails again and throw a code which is inevitable I think. My inclination is to mention it to them, and even if they can't do anything, at least it's documented.

Edit: I should add that my Lemon Law window runs out on April 16, and as much as I hate to say it that's concerning me. If the car is never going to be right again I don't want to be stuck with it and take a huge financial hit, sentimental attachment or not. Sometimes I feel like I have the crappiest luck.


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## TDCruze (Sep 26, 2014)

Something is definitely not right, it should not accumulate soot this fast. I doubt it would be from lugging, these engines seem to happily run at 1300 RPM even in the 9 speed auto. 

Its possible the DPF is damaged or contaminated from the turbo issue, or dealer installed wrong oil? (dexos 1 instead of dexos 2?) But, if so why did the soot % go down to 2% after the regen. I believe these cars use a pressure differential between the upstream and downstream sides of the DPF to determine soot load. If its partially plugged it should not go to 2% I would think. 

EGR could be the most likely problem, as the symptoms of surging, higher fuel consumption and rapid soot load accumulation do fit with a stuck open EGR.
Interestingly a failed turbo is a symptom of a stuck closed EGR valve. 

As for why you are not getting a CEL I am not sure.


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## BodhiBenz1987 (Jan 13, 2018)

I actually just had the thought about the oil while I was reading about common DPF problems, and double checked my first oil change receipt from August. Sure enough it says Dexos 1. I don't know why I didn't notice then. It was at the dealership and was the "drive up" type and I reminded the guy multiple times it was a diesel and needed Dexos 2, to the point I felt I was insulting him. I had it changed again at 12k miles (after the turbo replacement) and I did check the part number on that receipt and it is for Dexos 2. I swear the old sticker said Dexos 2 as well though, and I cannot imagine he could have been thick enough to put in Dexos 1 when I reminded him it was Dexos 2 AND it says it on the oil fill cap. I really have no way of knowing now though, because they could have just put the wrong thing on the invoice and right thing in the car. Timing wise it would line up though ... regens got more frequent a couple months after that. 

TDCruze I'm inclined to think like you that it would not go to 2% if it were clogged, though. So I don't know if that is the cause or coincidence. 

I made an appointment to take it in April 1, earliest they had. I will bring the 6k-mile oil change receipt. Interestingly the first oil change was done at the dealer-operated "quick lube", which is where they send you when you make an oil change appointment at the dealer. I was not impressed. My second oil change was done at the actual dealer service area because the car was already in for something else, and they seemed to get everything right. I hope the dealer stands behind the quick lube; they advertise it as their own service but it is operated by another business which I did not feel good about to begin with.


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## TDCruze (Sep 26, 2014)

Have you checked your oil level by chance since your last service? Just want to make sure it's not significantly over filled.


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> Have you checked your oil level by chance since your last service? Just want to make sure it's not significantly over filled.


It actually looks a bit high but not majorly. It's at the very top of the fill mark. I'll double check when I get home after it's sat a while. The first oil change I ever had in my 2005 Jeep diesel they managed to put 12 quarts in when it takes 6.4. I learned after that to check the level every time someone else changes it, but I guess I should start sending an oil sample out to the lab too ?


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## TDCruze (Sep 26, 2014)

BodhiBenz1987 said:


> It actually looks a bit high but not majorly. It's at the very top of the fill mark. I'll double check when I get home after it's sat a while. The first oil change I ever had in my 2005 Jeep diesel they managed to put 12 quarts in when it takes 6.4. I learned after that to check the level every time someone else changes it, but I guess I should start sending an oil sample out to the lab too ?


It should be fine then, I was thinking something like what happened with your Jeep. 
At nearly double the oil volume in your diesel, you are lucky the engine did not have a run away!!!

This is exactly why I do not generally take my vehicles to anyone for work unless I must. I have taken the Cruze in for the "free" oil changes, with apprehension over the Dexos 1 and 2 mix up concern as well. My Dodge Journey the dealer put almost 2 extra quarts in. I was busy and it was there for warranty work. Just reminds me why I like to do it myself.


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> It should be fine then, I was thinking something like what happened with your Jeep.
> At nearly double the oil volume in your diesel, you are lucky the engine did not have a run away!!!
> 
> This is exactly why I do not generally take my vehicles to anyone for work unless I must. I have taken the Cruze in for the "free" oil changes, with apprehension over the Dexos 1 and 2 mix up concern as well. My Dodge Journey the dealer put almost 2 extra quarts in. I was busy and it was there for warranty work. Just reminds me why I like to do it myself.


I tend to like to do things myself for the same reason, especially after the Jeep incident. I was amazed it basically showed no ill effects even though I drove it 100 miles with the overfilled oil ... it never occurred to me to check, but my dad had had his twin Jeep's oil done the same day, and called to see if they had overfilled mine like his. The funny thing is I ended up using the dealer for the Cruze for the same reason I had chosen the dealer for my Jeep's first oil change ... figured it would be "safe" while I'm still learning about the car, cover me in case of something going wrong, etc. I wish I'd been "ruder" about making sure it was the right oil. I never want to
sound condescending but right now the track record of cars I've owned merits it. Fun fact: I have four cars right now and three of them had something careless done at a dealership on their first oil change; the two Jeeps, the Cruze, and my 87 Mercedes, which they never changed the break-in oil filter on the first change in 1987.
I guess I shouldn't speculate too much though until I get the car in there and they can look at it. On a whole I really like the dealership and the people there so I hope they will help. The Jeep dealer that messed up my Jeep was less helpful from the start.


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## TDCruze (Sep 26, 2014)

BodhiBenz1987 said:


> I tend to like to do things myself for the same reason, especially after the Jeep incident. I was amazed it basically showed no ill effects even though I drove it 100 miles with the overfilled oil ... it never occurred to me to check, but my dad had had his twin Jeep's oil done the same day, and called to see if they had overfilled mine like his. The funny thing is I ended up using the dealer for the Cruze for the same reason I had chosen the dealer for my Jeep's first oil change ... figured it would be "safe" while I'm still learning about the car, cover me in case of something going wrong, etc. I wish I'd been "ruder" about making sure it was the right oil. I never want to
> sound condescending but right now the track record of cars I've owned merits it. Fun fact: I have four cars right now and three of them had something careless done at a dealership on their first oil change; the two Jeeps, the Cruze, and my 87 Mercedes, which they never changed the break-in oil filter on the first change in 1987.
> I guess I shouldn't speculate too much though until I get the car in there and they can look at it. On a whole I really like the dealership and the people there so I hope they will help. The Jeep dealer that messed up my Jeep was less helpful from the start.


That was one thing that I have wondered about, was whether or not the oil filter has been changed on the Cruze? I am sure it was, the oil was new and filled perfectly, but I still have that thought.

I guess your '87 survived it's mishap as well as the Jeep. Hope the dealer can help find the source of the problem.
Sometimes it's hard to get them to look into it to hard without any CEL.


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> That was one thing that I have wondered about, was whether or not the oil filter has been changed on the Cruze? I am sure it was, the oil was new and filled perfectly, but I still have that thought.
> 
> I guess your '87 survived it's mishap as well as the Jeep. Hope the dealer can help find the source of the problem.
> Sometimes it's hard to get them to look into it to hard without any CEL.


The Mercedes was fine and now has 314k miles on the original engine (original turbo too). It has had a long life of ups and downs but was the most reliable car I've had so far. The only thing that stopped it was rust and I am working on that (slowly) so it will live again. The Jeep is still good as well at 139k miles ... has had some issues but all very typical for the car and I think it has done better than many of its kind. So hopefully my Cruze can join as a survivor. The hardest thing might be pinpointing a problem that can be (or will be) addressed now. Technically there's nothing that says there is a failure. On the optimistic side the service adviser was quick to give me an appointment, so at least they are willing to look into it to begin with.


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## Barry Allen (Apr 18, 2018)

BodhiBenz1987 said:


> Edit: I should add that my Lemon Law window runs out on April 16


The warranty on emissions equipment is generous: "From the first 2 years or 24,000 miles to 3 years or 36,000 miles, defects in workmanship continue to be covered under the New Vehicle Limited Warranty Bumper-to-Bumper coverage. Specified major components are covered for the first 8 years or 80,000 miles, whichever comes first, see dealer for details."

I'm pretty sure the DPF is one of those "major components" covered. If the car continues to regen frequently, they might owe you a new DPF.


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## BodhiBenz1987 (Jan 13, 2018)

Barry Allen said:


> The warranty on emissions equipment is generous: "From the first 2 years or 24,000 miles to 3 years or 36,000 miles, defects in workmanship continue to be covered under the New Vehicle Limited Warranty Bumper-to-Bumper coverage. Specified major components are covered for the first 8 years or 80,000 miles, whichever comes first, see dealer for details."
> 
> I'm pretty sure the DPF is one of those "major components" covered. If the car continues to regen frequently, they might owe you a new DPF.


I think you are right and I hope that's the case. I'm very good at imagining worst-case scenarios. But much as I complain about new technology, at least tech makes it is easy to document the regens, plus they can look at the data themselves and see that average, or take it for a drive and look at the soot numbers change.


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## IndyDiesel (May 24, 2015)

I had a stuck open EGR on my gen 1 and it prevented it from starting, took it out and cleaned it and everything was fine. It might be a good idea to just remove yours and clean it prior to going to dealer.


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## BodhiBenz1987 (Jan 13, 2018)

IndyDiesel said:


> I had a stuck open EGR on my gen 1 and it prevented it from starting, took it out and cleaned it and everything was fine. It might be a good idea to just remove yours and clean it prior to going to dealer.


I think with the warranty I would be better to just not touch anything and risk creating any complication. I am going to mention the EGR when I go in though. Not that they probably need my suggestions but I'd like some reassurance that that is checked.

What I'm debating is how much to drive it (if at all) before I take it in. I could drive my Jeep though it's waiting on a thermostat so I'm not keen on driving it a ton (too cold not too hot). I'm also wondering if leaving the Cruze sitting for a week would further muddy the waters since they don't like sitting. I may just drive it sparingly until I can find out more. Not sure it will matter either way at this point though, already been driven a lot in this condition since I really had no way of knowing anything other than the short time the CEL came on.


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## IndyDiesel (May 24, 2015)

They are likely to not find anything and say this is normal.


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## BodhiBenz1987 (Jan 13, 2018)

IndyDiesel said:


> They are likely to not find anything and say this is normal.


I don't think they will say it's normal. The data is so obviously not normal. The service adviser already acknowledged the concern as far as the frequency of regens when I set up the appointment. However they still may not find any cause, in which case, yeah, they'll just say drive it until a CEL comes on. That's my biggest concern to be honest. Then I'm stuck with a poorly operating car that I can't get fixed or bought back. But, I'm trying to just be patient and not think the worst before I have even gotten there. So far they have been pretty supportive so I think they will at least try. The documented incorrect oil change, whether the cause or not, may give my concerns a little extra clout too.


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## BodhiBenz1987 (Jan 13, 2018)

The car went in this morning and so far they can't find out what's wrong. They are keeping it another day and hoping to find out something tomorrow. I did tell the service adviser about the Dexos 1. At least they seem to be taking the whole thing seriously and they are trying, which I appreciate. It's very frustrating because over the last week I have done a lot of research and feel that the behavior is most likely due to ash build up on the DPF surfaces preventing it from working efficiently, but not enough to block it significantly and trigger a CEL. From looking at cutaways and designs it would not take much to compromise surface area. The timing and the symptoms just line up and it's the Occam's razor. But I think there isn't any proof unless you take it out and cut it up. Fingers crossed.


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## BodhiBenz1987 (Jan 13, 2018)

Well, the car spent three days at the dealer and they found nothing wrong. They contacted GM Technical Support, who sent them a bulletin stating what I'm experiencing is normal; saying it depends on driving but on average the car should be expected to do a regen once every tank of fuel. So apparently GM thinks our cars go 150 miles or less on a tank of fuel ... or more likely they gave a canned response that doesn't address the stated behavior because they don't give a crap (GM, not the dealer). I got more irate than I would have liked and managed to convince the dealer to replace the DPF considering the oil mishap would potentially have damaged it regardless of whether it is the cause of this specific problem. Credit to them for doing so, I do appreciate that. I got the car back Saturday and sadly there is no noticeable improvement. It did a regen 100 miles after the DPF replacement. I had held out hope maybe the sensors needed to recalibrate themselves or something but it's still filling up with soot like mad on the highway. My driving since getting the car back has been almost entirely highway. So now I still have a lousy car _and_ feel like an idiot for insisting this was the problem. 
At this point unfortunately I think I am just done. I have no recourse to get this fixed, the dealer did everything they could and seemed to check everything, and GM doesn't know or care how the cars they built work. Then again I have no recourse to get GM to buy it back (it's "normal") so to offload it I would take a huge hit financially including on the useless extended warranty I bought. I might take it to another dealer just in case a fresh set of eyes comes up with something. But barring them finding anything I don't see how I can keep this car. It's drivable and actually still a great car for 80 out of every 100 miles. But I can't put up with a regen and its symptoms and wear and tear every day, which is what it will be in the summer when I'm commuting to where I volunteer daily. More than anything I'm worried about the inevitable future failure or even fire hazard, and constantly having to worry about stopping during a regen (had to take a couple laps around my intended destination yesterday for this reason, not convenient).
Anyhow I will keep it for a while and just see. Maybe it will go uphill or downhill and make a decision easier.


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## TDCruze (Sep 26, 2014)

Did they check the EGR valve?


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> Did they check the EGR valve?


As far as what they said, yes, but I am not sure exactly what checking it involved. Maybe they only meant they checked EGR-related data, so maybe I'll call to clarify. They said there was no blow-by or other signs of engine problems. I did also send an oil sample to Blackstone and though it's hard to get a lot of info from a short run, then did say there was no unusual soot buildup in the oil, or wear metals, etc, everything looked good.

The car seemed to do a little better on a drive I just took this evening in terms of soot load buildup. I'm holding out a tiny bit of hope that maybe it is stabilizing after the DPF replacement, but maybe it was just because it is very warm out today (80 degrees). I will probably just drive it the next week and see what happens, then try to make an appointment at the other nearby dealer.


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## Rivergoer (Mar 30, 2017)

One regen (or MAYBE two) every tank of gas is about right...but it sounds like you’re doing upwards of 5 or 6 per tank, that’s certainly NOT normal.

Sorry to hear the news, gotta be frustrating for sure.


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## TDCruze (Sep 26, 2014)

BodhiBenz1987 said:


> As far as what they said, yes, but I am not sure exactly what checking it involved. Maybe they only meant they checked EGR-related data, so maybe I'll call to clarify. They said there was no blow-by or other signs of engine problems. I did also send an oil sample to Blackstone and though it's hard to get a lot of info from a short run, then did say there was no unusual soot buildup in the oil, or wear metals, etc, everything looked good.
> 
> The car seemed to do a little better on a drive I just took this evening in terms of soot load buildup. I'm holding out a tiny bit of hope that maybe it is stabilizing after the DPF replacement, but maybe it was just because it is very warm out today (80 degrees). I will probably just drive it the next week and see what happens, then try to make an appointment at the other nearby dealer.


I highly doubt they pulled the EGR valve out to actually look at it or clean it. Likely did a computer diagnostic at most, maybe just figured no code no problem? 
Definitely worth following up on this if your high regen frequency continues. 



Rivergoer said:


> One regen (or MAYBE two) every tank of gas is about right...but it sounds like you’re doing upwards of 5 or 6 per tank, that’s certainly NOT normal.
> 
> Sorry to hear the news, gotta be frustrating for sure.


Yeah, every 100 miles seems excessive even if all city driving. One a tank seems to be about the average for most. 

I am not sure if I see or notice every regen, but I am pretty sure mine is at most one a tank. I have only interrupted a regen 2 times in 13,000 miles, but I am about 85% highway.


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## Barry Allen (Apr 18, 2018)

If GM can't fix the car and you can't force them to buy it back with a lemon law, your best option might be to DPF delete when a tuner comes out with an engine tune and straight pipe option.


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> I am not sure if I see or notice every regen, but I am pretty sure mine is at most one a tank. I have only interrupted a regen 2 times in 13,000 miles, but I am about 85% highway.


This was my experience in the first 8k miles or so. I only remember a couple times in a 6-7 month span where the fan kept running after I shut it off, and that was how I knew. There were a couple times I noticed a dip in mpg too and suspected a regen. I never really even thought about regens. Around November is where I really noticed but I suspect it was starting to increase before that (based on the all-time avg being so low). That's why I just felt the oil thing is kind of the Occam's Razor. I will see what I can find out about the EGR. It's kind of a tough situation also in terms of keeping goodwill with the dealer ... I know they hate it when people question their knowledge and act like a know-it-all, and I have already crossed the line quite a bit. On the other hand I'm always willing to admit I do not know it all, but I know a little bit and a suggestion can sometimes provide the outside thought that can lead the professionals to the right place.
@Barry Allen, the delete option has occurred to me too, though it would void the warranty and having a warranty was an important part of buying a new car. Of course the warranty isn't helping me now, but if I have a DMF failure or other typical issue it would sure be nice. I don't live in a smog-test state though so it's possible.


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## IndyDiesel (May 24, 2015)

Unfortunately this is what I expected, this is normal routine by GM and the dealer. We as consumers know what is normal. I only had a couple of times that the regen really effected the drive ability of the car while it was doing that. I had some times it would do frequent regens, in retrospect some of that may have been due to a very dirty EGR, like I stated before, I would find the egr on your car, mine was two or three bolts and remove, inspect and clean, I am not the most handy guy and I did it on a gen 1. GM has made such a small quantity of gen 2 diesels I don’t think they support it as well as we expect. I cleaned mine with MAF cleaner, mine was a mess at about 40k miles. I think the egr is something if you are going to keep car is a regular maintenance item, in addition, the only way you know for sure the correct oil is used is to watch dealer/mechanic put correct oil in or just do it yourself. These modern diesels that are not deleted are and can be very fussy and frustrating when problems occur.


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## Barry Allen (Apr 18, 2018)

BodhiBenz1987 said:


> the delete option has occurred to me too, though it would void the warranty and having a warranty was an important part of buying a new car. Of course the warranty isn't helping me now, but if I have a DMF failure or other typical issue it would sure be nice. I don't live in a smog-test state though so it's possible.


Aftermarket and after-purchase modifications only affect the warranty if the modification cause problems. Example: Putting a new stereo in a car (commonly done years ago, before cars had decent stereos) doesn't mean the manufacturer can refuse to fix a transmission that goes out. One thing has to affect another.

If you get a DPF delete straight pipe and an engine tune that does nothing other than delete the DPF (stop warning lights from occurring), Chevy still has to warranty the things not affected. DMF failure? They have to cover that if you didn't do anything like install a tune that increases engine power.

Still, YMMV on this. If Chevy does the routine "warranty on your engine is denied because you have that Jack In The Box antenna topper installed..." you'd probably have to at least take them to small claims court to settle any warranty claims. I had success with a prior warranty claim when I had to sue Hyundai of America, and they just settled without going to trial. My state requires a management official (at least a company manager of VP) to show up for small claims cases when you sue a company, and they weren't going to send someone from California to Illinois to argue over a warranty issue. Still, it's something to keep in mind.


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## resurgent cineribus (Feb 26, 2019)

Sorry this is probably more a rant than anything helpful but GM should really step up for something like this. Yes this is a low volume powertrain and it probably isn't fair to expect the dealer to have an expert on these engines/emission systems on hand. Send an engineer over to the dealer if necessary who specializes in these. It will cost them a bit but it will help ensure customer loyalty and satisfaction in the long run. Nobody expects these cars to be 100% problem free but we do expect some help from GM if necessary while under warranty. 

Sadly I fear these cars were not profitable enough for GM to really make an effort in supporting them properly hence them killing the Cruze altogether. If this were a 1 ton Diesel pickup having this issue with a sticker of 80k I bet you'd get more attention. I love my CTD but it was definitely a leap of faith especially since I bought it used so I only have half a warranty then I'm on my own. I've always had Fords that were older and rarely had an issue I couldn't figure out myself (fortunately since they were all long out of warranty) admittedly they were much less complex than these. 

Ok end of rant. I'm still pretty new to these myself but if there are no codes I might agree on checking/cleaning the EGR if it isn't too hard to get to but I probably wouldn't dig much deeper under warranty. I have one of the Bluedriver OBD2 devices; if you have one of those (or similar) you could use it to log data while driving which might provide a clue (at least to someone who can better analyze the results) Just an idea, it will let you monitor sensor data during a drive cycle to see if something looks off.


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## Barry Allen (Apr 18, 2018)

resurgent cineribus said:


> Yes this is a low volume powertrain


Nothing is stopping GM from offering this engine in other car models. I wondered why the Malibu doesn't offer this diesel engine and automatic transmission.


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## IndyDiesel (May 24, 2015)

Why offer it in your flagship car when they cant seem to figure out emission issues on the Cruze diesel? I loved the economy and driving my diesel while I had it but I never had any serious issues. When you do have serious issues, getting support from GM and your Chevy dealer can be a nightmare!


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## Barry Allen (Apr 18, 2018)

IndyDiesel said:


> Why offer it in your flagship car when they cant seem to figure out emission issues on the Cruze diesel? I loved the economy and driving my diesel while I had it but I never had any serious issues. When you do have serious issues, getting support from GM and your Chevy dealer can be a nightmare!


Since when is a Malibu a flagship car for Chevy?


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## IndyDiesel (May 24, 2015)

Barry Allen said:


> Since when is a Malibu a flagship car for Chevy?


Ok, it’s about the only car....yikes. You get my point.


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## resurgent cineribus (Feb 26, 2019)

Since they are offering this same engine in the equinox/terrain hopefully that leads to dealers getting better training on this particular engine. Even if it is poorly marketed the sheer volume of those things being sold will probably exceed the number of Cruze's that got the engine. I like the Malibu myself if I were looking for a sedan. I think they were rated 29/36mpg freeway on the gas model which is pretty impressive for a roomier car. At least GM is keeping the Malibu around for now. Still can't believe Ford is even killing off the Fusion; it may be one of the last economical sedans left from the domestic makers.


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## johnmo (Mar 2, 2017)

Barry Allen said:


> Nothing is stopping GM from offering this engine in other car models. I wondered why the Malibu doesn't offer this diesel engine and automatic transmission.


I was also thinking this the other day. The 1.6 TD seems to be a great little engine. It'll be a while (I hope) before I'm looking to replace my Cruze, but I would be a buyer for a diesel Malibu when the time comes.

I think the other issue with the Malibu is that they already have (or had -- haven't kept up and they may have killed it) a hybrid assist eco option. But, if it's the only sedan offered, I think they should offer as many options and configurations on it as they can.


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## Barry Allen (Apr 18, 2018)

johnmo said:


> I think the other issue with the Malibu is that they already have (or had -- haven't kept up and they may have killed it) a hybrid assist eco option. But, if it's the only sedan offered, I think they should offer as many options and configurations on it as they can.


The Malibu hybrid is probably the thing killing any marketing potential. GM has already sunk costs into development of the hybrid powertrain, and that's a big marketing thing. To offer a diesel means some minimal costs for certifying the powertrain option, but it wouldn't be a huge deal to put the diesel engine with the 9-speed auto (the transmission already sold with the 2.0 gasoline turbo engine option). Still, additional costs to add one more powertrain option when they want to sell hybrids to everyone who wants. them.


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## BodhiBenz1987 (Jan 13, 2018)

Some updates after a few more days: a little promise in terms of the soot levels ... after that first regen following the DPF replacement the soot level went up to 40% pretty quickly but then stabilized a little and has been slower since. I am at 369 miles with 76% soot right now, which is maybe not perfect but certainly way ahead of where I have been. So I hope that means the DPF was the problem and it just had to "recalibrate". The bad news is I seem to have an exhaust leak somewhere in the engine compartment, and I hope this isn't the reason for the improved soot levels (i.e. all the soot is going into the air instead of the DPF!). It is all over the wastegate actuator and the hoses and lines surrounding it, which I guess would be due to something leaking at the turbo? The area where the DPF connects does not seem to have the soot near it, the leak is on the intake side. Photo included. It definitely smells which I thought was due to the recent work (grease gets places and stinks) but it now appears to be a leak. So I guess it's going back to the dealer again. I hope the longer regen cycle will continue once I get the exhaust issue fixed. What a mess. Today is a year since I took delivery of the car and wish I could feel like that were something to celebrate. :sad010:


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## TDCruze (Sep 26, 2014)

I would guess that they didn't tighten something enough or there is a gasket problem due to the removal and installation of your new DPF. I would think they likely had the turbo off during in the installation. 

Definitely leaking enough to be a concern. 

Unfortunately, back to the dealer you go...

Likely cannot determine if your other previous issue is solved due to the leak possibly skewing your results.


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## BodhiBenz1987 (Jan 13, 2018)

On further look it definitely seems to be the clamp at the DPF where the leak is. The clamp looks a little crooked so that is probably why. Unfortunately probably also explains my improved soot levels in the DPF. I'm guessing there shouldn't be that much soot even pre-DPF?? Maybe that tells me something. I hope otherwise because I'm beyond done with this. The car has been in the dealer for 6 weeks of the last three months.


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## BodhiBenz1987 (Jan 13, 2018)

BodhiBenz1987 said:


> On further look it definitely seems to be the clamp at the DPF where the leak is. The clamp looks a little crooked so that is probably why. Unfortunately probably also explains my improved soot levels in the DPF. I'm guessing there shouldn't be that much soot even pre-DPF?? Maybe that tells me something. I hope otherwise because I'm beyond done with this. The car has been in the dealer for 6 weeks of the last three months.


Edit: after trying to put in perspective what the 22-25 grams of soot it takes to trigger a regen looks like, I would say the amount that's been dumping into the engine bay pre-DPF is more than enough to account for the longer regen cycle. False hope is a painful thing.


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## BodhiBenz1987 (Jan 13, 2018)

Back from the dealer after sitting 2.5 hours. They said it needs another DPF because this one doesn't seat right and they can't fix it. I have to wait another week for that. Gave me the car back and now it not only still leaks (smells awful) but now also surges at idle and boost dips to -6 PSI. The car gets worse every time they touch it. None of this is warranty work so I don't get a loaner. I could not have made up a worse new-car experience than this has been if you had asked me to. I can't even cut my losses because how am I supposed to sell this car with its issues and history?


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## johnmo (Mar 2, 2017)

BodhiBenz1987 said:


> None of this is warranty work so I don't get a loaner. I could not have made up a worse new-car experience than this has been if you had asked me to. I can't even cut my losses because how am I supposed to sell this car with its issues and history?


How in the world is this not warranty work on a one-year-old car?

My first-year experience was also very bad. Of all the cars I've been around in my family -- new and used -- my Cruze in its first year spent more time in the shop than any of them and it's spent more time in the shop total than most of my other cars combined.

The second year has been much better. There have been some dealer disappointments around getting my fog lights installed and some other little things, but the car has been super reliable for about the last 16 months. So, maybe stick with it until the bugs are worked out and see how it goes?


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## BodhiBenz1987 (Jan 13, 2018)

johnmo said:


> How in the world is this not warranty work on a one-year-old car?
> 
> My first-year experience was also very bad. Of all the cars I've been around in my family -- new and used -- my Cruze in its first year spent more time in the shop than any of them and it's spent more time in the shop total than most of my other cars combined.
> 
> The second year has been much better. There have been some dealer disappointments around getting my fog lights installed and some other little things, but the car has been super reliable for about the last 16 months. So, maybe stick with it until the bugs are worked out and see how it goes?


Sorry, wasn't clear about the warranty. The dealer replaced the DPF on their dollar (I am pretty sure, though I should clarify as they did not specifically say) since it was done as a corrective action for their tech's oil mistake. The leak is due to the new DPF, so I assumed it is their bill not the warranty to fix that as well. As far as I know, if I have another problem that is not directly related, it would go back to warranty coverage. I might give them a call and ask if a loaner is possible either way. I think even with warranty work if the car is drivable they give it back to you rather than a loaner so maybe that is the case here. I drove it today and it seemed OK but it makes me uncomfortable and I feel a bit embarrassed because it really does smell to the point I know people in traffic and parking lots probably notice.

I am trying to hold out hope mine will be like yours. It just seems like each time I get it back I'm ready to move on and begin anew, but then something else comes up. Maybe the soot numbers will actually stay improved even with the exhaust fixed, in which case it would be a step forward and maybe just a small setback.


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## johnmo (Mar 2, 2017)

BodhiBenz1987 said:


> The dealer replaced the DPF on their dollar (I am pretty sure, though I should clarify as they did not specifically say) since it was done as a corrective action for their tech's oil mistake. The leak is due to the new DPF, so I assumed it is their bill not the warranty to fix that as well.


Dealer screwed up. Dealer should be taking EXCELLENT care of you.


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## BodhiBenz1987 (Jan 13, 2018)

The exhaust is fixed and as expected the soot improvement was all only due to the leak. Soot level was 82% when I picked it up and it went to 100 and did a regen within 5 miles. In 73 highway miles since it's already at 59% soot and climbing steadily. The car is slower and the mpg is worse than ever. No idea what to do. I've already missed a few things that were important to me due to not having a reliable car, and I have to cancel a trip I wanted to do next month (it will do 10 regens or more on the trip and who knows what else will go wrong, plus it's generally unpleasant to drive). But there's no point to taking it back to that dealer or another one when nothing is "wrong" with it. It is beyond me how none of this is throwing any code. I just don't understand this or why it happened. Tomorrow I will call GM but I'm guessing they will leave me for dead on this. This is the level of reliability and support I expect from a $1,500 "as-is" used car purchase on Craigslist.


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## resurgent cineribus (Feb 26, 2019)

Sorry to hear about all the car trouble; sounds like a nightmare. 

At this point I think you need to put some more pressure on the dealer/GM even if it means getting a little unpleasant. It sounds like nobody bothered to road test it to catch the soot/exhaust leak issues and just gave it back despite the troublesome history you've already had meaning they either didn't care enough to fully test or knew it still wasn't right and gave it to you anyway. It sounds like all this started with the botched oil change right? though it may be hard to prove. GM and the dealer can fight over who foots the bills but one or both parties should be paying. 

Either the dealer can pressure GM to provide more technical support on the issue or you can bypass them and do so directly (probably the former is better) Providing a loaner care is the very least they could do (or covering a rental) but you may need to be forceful that they do whatever it takes to get this right. Trust me I'm usually too much a nice guy (aka pushover) but I've learned how to get aggressive when the situation calls for it. If you still can't get anywhere I think the next step would be either a lemon law case or small claims court. 

I recently found a skilled welder who was able to repair my whole strut tower situation on my old escape and though it set me back $900 I now have another car that has been dead reliable I'd prefer to hold on to. It has been great for saving the short trips on my cruze and giving me a backup car if mine is unavailable but I know many don't have that option. At 33 years old the cruze is my first car to have any warranty and If I had a similar experience it would probably be the last time I'd take on a loan on a newer car. Otherwise it would all be craigslist cash deals for me; at least then I know I'm on my own for repairs (and if they are too much I can cut my losses and scrap it)

best of luck


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## BodhiBenz1987 (Jan 13, 2018)

resurgent cineribus said:


> Sorry to hear about all the car trouble; sounds like a nightmare.
> 
> At this point I think you need to put some more pressure on the dealer/GM even if it means getting a little unpleasant. It sounds like nobody bothered to road test it to catch the soot/exhaust leak issues and just gave it back despite the troublesome history you've already had meaning they either didn't care enough to fully test or knew it still wasn't right and gave it to you anyway. It sounds like all this started with the botched oil change right? though it may be hard to prove. GM and the dealer can fight over who foots the bills but one or both parties should be paying.
> 
> ...


Thanks and I'm glad to hear you got your Escape fixed up. I'd really be stuck if I didn't have my older cars to fall back on, even though they have their own issues. I've been trying to use the Jeep for short trips as well, or if I ever finish the brake job, my 78 Mercedes. I'd love for the new one to be reliable enough that I can set the Jeep aside and do a few repairs to make it better. 
I have the same problem that I just am not naturally aggressive and get very uncomfortable when I have to be. I already feel awkward because I was pretty aggressive about the DPF. And there is always a balance, where being patient/kind is more productive than being demanding ... but in this kind of situation I'm trying to find where the right line is.
Over the weekend there has been some improvement, but still not what it's supposed to be. It has stabilized somewhat around 70% ... still going up but slowing down and I occasionally see it drop a point or two. It just does not do that under the scenarios I know it is supposed to (highway). It kind of does the opposite of what I expect: rises on the highway and drops a point or two around town. I figured I would give it a week or so and just see. I don't really understand how the soot % sensors work but it almost seems like they have to "learn" ... i.e., with a brand new DPF put in, they held the same reading of 82% before the repair.
One thing I'm struggling with is that I get inconsistent feedback as to whether that oil really makes a difference. I'm inclined to think it did, but I've also heard some people say it shouldn't make a big difference unless the car is burning a lot of oil and the wrong oil is run for a few intervals. But imo if GM can void your warranty for you using it, they should take corrective measures when they use it. If the new DPF does better that tells me something to some degree, but I'm going to wait until I have more data.
I noticed something else yesterday by chance which I am taking it in for next week, which is some damage to the bottom of the intercooler. I suspect this was sustained last fall when I hit a tire tread. I had it inspected right away at that time by the dealer and also assessed at a body shop and neither mentioned it but I want it checked anyway. It seems to be mostly contained to the bottom row of fins but there is one area the crunch goes up into the bottom intake air channel. It's pretty minor damage but enough to make me want to check for a boost leak which would be consistent with my problems.


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## IndyDiesel (May 24, 2015)

Have not read your thread for a bit, it sounds like you have a messed up car, I would be very direct but professional with the dealer and GM, I have a tendacy to loose my cool sometimes when in a situation like yours. I had my Cruze premier basically mistakenly stolen by another customer at the Chevy Dealer that thought my car in for an oil change was her loaner car, so she drove away in my car instead of the rental. I blew a gasket when I just go in for an oil change and now they cant find my car. So the squeeky wheel gets the attention, you need to share your displeasure and do it NOW. I have no tolerance for a new car and lots of problems.

Good luck.....


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## BodhiBenz1987 (Jan 13, 2018)

IndyDiesel said:


> Have not read your thread for a bit, it sounds like you have a messed up car, I would be very direct but professional with the dealer and GM, I have a tendacy to loose my cool sometimes when in a situation like yours. I had my Cruze premier basically mistakenly stolen by another customer at the Chevy Dealer that thought my car in for an oil change was her loaner car, so she drove away in my car instead of the rental. I blew a gasket when I just go in for an oil change and now they cant find my car. So the squeeky wheel gets the attention, you need to share your displeasure and do it NOW. I have no tolerance for a new car and lots of problems.
> 
> Good luck.....


I'm definitely about to blow a gasket. This is so unfair and confusing. It actually did a little better since the new DPF, and made it to 400 miles ... not ideal but better. So I thought, hey, maybe after the next regen it will actually start going towards normal. Again, I should learn not to hope. It did a regen on the highway, and I stayed on the highway for 35 miles ... went up to 50% soot in that distance. Out of curiosity I took it back on the highway for a while. After 62 miles it's at 82% soot. 82%!!!!!!! So I'm going to going to get the next regen after less than 100 miles this time, worse than ever.

I think the hardest thing about fighting is that there is no possible winning outcome. The best outcome is they buy back my beloved car that I special-ordered and cannot ever replace, and I can wonder if it got crushed or fixed and sold to someone else, and never know what happened. The other outcome is they tell me the car is fine, call back when you have a CEL, and I have a $25k car I can't drive and no money to buy another car. And then I can hire a lawyer to try to get to the "good" outcome at a huge loss of time and money. It doesn't matter how much I yell at the dealer, they don't know how to fix it.


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## IndyDiesel (May 24, 2015)

BodhiBenz1987 said:


> I'm definitely about to blow a gasket. This is so unfair and confusing. It actually did a little better since the new DPF, and made it to 400 miles ... not ideal but better. So I thought, hey, maybe after the next regen it will actually start going towards normal. Again, I should learn not to hope. It did a regen on the highway, and I stayed on the highway for 35 miles ... went up to 50% soot in that distance. Out of curiosity I took it back on the highway for a while. After 62 miles it's at 82% soot. 82%!!!!!!! So I'm going to going to get the next regen after less than 100 miles this time, worse than ever.
> 
> I think the hardest thing about fighting is that there is no possible winning outcome. The best outcome is they buy back my beloved car that I special-ordered and cannot ever replace, and I can wonder if it got crushed or fixed and sold to someone else, and never know what happened. The other outcome is they tell me the car is fine, call back when you have a CEL, and I have a $25k car I can't drive and no money to buy another car. And then I can hire a lawyer to try to get to the "good" outcome at a huge loss of time and money. It doesn't matter how much I yell at the dealer, they don't know how to fix it.


I am not suggesting you need to blow a gasket. I think just sharing the facts in a professional direct way and summarizing what has happened is a more prudent way to deal with it. If they can’t fix it is even worse, than something broken and they just fix it. If they can’t fix now, what’s it going to be like when the warranty has expired and now when they are guessing it costs a lot of money and even more frustrated. I guess I have been fortunate, I have never bought a new car and then had major issues, really haven’t had used cars with major issues either.


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## BodhiBenz1987 (Jan 13, 2018)

IndyDiesel said:


> I am not suggesting you need to blow a gasket. I think just sharing the facts in a professional direct way and summarizing what has happened is a more prudent way to deal with it. If they can’t fix it is even worse, than something broken and they just fix it. If they can’t fix now, what’s it going to be like when the warranty has expired and now when they are guessing it costs a lot of money and even more frustrated. I guess I have been fortunate, I have never bought a new car and then had major issues, really haven’t had used cars with major issues either.


I think I have been lucky in hindsight, with other cars. The only other car I bought new was my Jeep, and it had a bunch of issues, but every single one a light came on, I took it to the dealer, and a day and $0 it was back good as new. The one exception was a hissing noise I told them about, when it was 3 years old, and they told me it was the normal sound of the turbo spooling up ... I insisted the diesel specialist on their staff look at it ... he took about 3 seconds to diagnose it as a leaking turbo hose, and maybe 5 minutes to replace it. My Mercedes 300D made it to 314k with basically normal wear and tear stuff, and the only reason I had to stop driving it was rust. Hopefully however the Cruze situation turns out, when I am done the battle, I can use my time to finish fixing up the 300D and at least I'll have something. I would drive that car anywhere.


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## MRO1791 (Sep 2, 2016)

400 miles for a regen is just under average. My manual does an average of 500 miles between regens, but I've had several as short as 250, some longer. It's quite variable. The car does in fact have to "learn" with the new DPF, if I had to guess I'd say it was the original issue post bothced oil change. That said, definitely check for an induction leak! That would cause excessive soot, surging and frequent regens. The dealership is the root of your problems from what I can tell. Do not go easy on them, and let GM corporate know about this issue. They should not be giving you an obviously not emmissions compliant vehicle back to drive! That could be a violation of federal emmissions laws and you might want to tell them as much! I bet they don't want the EPA paying them a visit! It's inexcusable that the botched the oil change, and it's gross incompetence that they bothced the DPF replacement! They should have checked for leaks! That is mechanic 101 level stuff! In my lemon experiences, the dealership "fixes" were responsible for additional problems, as it appears to also be the case in your experience

Sent from my Moto G (4) using Tapatalk


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## MRO1791 (Sep 2, 2016)

Oh, one other note, it's normal for soot to build up fast, then taper off at a slower rate, it's NOT linear. Most of that soot will build up in the first 100 miles or less, then build up rate slows after that. Don't be too focused on the % soot, it's not really a good measure when compared to miles. What kind of EGTs are you seeing? There is a fair amount of passive regen that happens at higher EGTs, around 600F and above. 

Sent from my Moto G (4) using Tapatalk


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> 400 miles for a regen is just under average. My manual does an average of 500 miles between regens, but I've had several as short as 250, some longer. It's quite variable. The car does in fact have to "learn" with the new DPF, if I had to guess I'd say it was the original issue post bothced oil change. That said, definitely check for an induction leak! That would cause excessive soot, surging and frequent regens. The dealership is the root of your problems from what I can tell. Do not go easy on them, and let GM corporate know about this issue. They should not be giving you an obviously not emmissions compliant vehicle back to drive! That could be a violation of federal emmissions laws and you might want to tell them as much! I bet they don't want the EPA paying them a visit! It's inexcusable that the botched the oil change, and it's gross incompetence that they bothced the DPF replacement! They should have checked for leaks! That is mechanic 101 level stuff! In my lemon experiences, the dealership "fixes" were responsible for additional problems, as it appears to also be the case in your experience
> 
> Sent from my Moto G (4) using Tapatalk


I was fairly pleased with the 400 mile interval and if that had continued I think I would have been ok with it. This cycle has been dramatically worse though ... I know it isn't linear and usually builds up faster earlier, but I am at 86% with only 62 miles and it is going up and up. It almost never goes down regardless of EGT. My EGTs seem fairly low but do go over 600 a fair bit on the highway. They always get high (700) when the car is warming up at low speed which seems weird. Mostly there stay between 500 and 650. Even when they are in the mid 600s on the highway I do not see the soot load go down. The only time I see soot % drop is when I'm coasting at lower speeds after I get off the highway, and probably engine braking a little, I may lose a point, but very rarely. I really don't understand why it would suddenly go from a 400-mile cycle to one that will be under 100 ... Same driving pattern for each. On the first one it also climbed pretty quick early on bit really slowed down around 50-60%. This time it just keeps rolling. Best I can hope is it's part of the "learning" process. It will do a Regen later today most likely so we'll see what it does after that.
Thanks for the advise on staying after the dealer. I am taking it back Tuesday to have then check for boost leaks, and I also made an appointment at another dealer Wednesday. In the meantime I'm going to call GM customer service and open a complaint so I can get rolling with them.


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## resurgent cineribus (Feb 26, 2019)

BodhiBenz1987 said:


> I'm definitely about to blow a gasket. This is so unfair and confusing. It actually did a little better since the new DPF, and made it to 400 miles ... not ideal but better. So I thought, hey, maybe after the next regen it will actually start going towards normal. Again, I should learn not to hope. It did a regen on the highway, and I stayed on the highway for 35 miles ... went up to 50% soot in that distance. Out of curiosity I took it back on the highway for a while. After 62 miles it's at 82% soot. 82%!!!!!!! So I'm going to going to get the next regen after less than 100 miles this time, worse than ever.
> 
> I think the hardest thing about fighting is that there is no possible winning outcome. The best outcome is they buy back my beloved car that I special-ordered and cannot ever replace, and I can wonder if it got crushed or fixed and sold to someone else, and never know what happened. The other outcome is they tell me the car is fine, call back when you have a CEL, and I have a $25k car I can't drive and no money to buy another car. And then I can hire a lawyer to try to get to the "good" outcome at a huge loss of time and money. It doesn't matter how much I yell at the dealer, they don't know how to fix it.


Well of course there is another possible (optimistic) outcome. Someone gets a second opinion or finds a specialist that gets to the root of the issue and puts these issues to an end. Not sure what the process would be but but if you are firm with the dealer maybe they can refer to another technician at another dealer than has dealt with these engines/systems more in depth. You need the Dr. House of mechanics who can find a root cause. 

Also I'm feeling like a noobie to the CTD here and maybe a dumb question but how are you determining the soot level and regen intervals? On my 18 CTD I have no idea when it is doing either. I mean once on the long drive home I noticed an otherwise inexplicable drop in MPGs for a bit and I figured that was probably a regen but I'd like to be able to monitor these myself on mine. Do you have an auxiliary monitor/gauge or something? I think I mentioned before I'm using my old car for short errands and such whenever possible to hopefully be easier on the whole emissions system. My commute to work is probably long enough to do a regen without issue most times.


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## BodhiBenz1987 (Jan 13, 2018)

resurgent cineribus said:


> Well of course there is another possible (optimistic) outcome. Someone gets a second opinion or finds a specialist that gets to the root of the issue and puts these issues to an end. Not sure what the process would be but but if you are firm with the dealer maybe they can refer to another technician at another dealer than has dealt with these engines/systems more in depth. You need the Dr. House of mechanics who can find a root cause.
> 
> Also I'm feeling like a noobie to the CTD here and maybe a dumb question but how are you determining the soot level and regen intervals? On my 18 CTD I have no idea when it is doing either. I mean once on the long drive home I noticed an otherwise inexplicable drop in MPGs for a bit and I figured that was probably a regen but I'd like to be able to monitor these myself on mine. Do you have an auxiliary monitor/gauge or something? I think I mentioned before I'm using my old car for short errands and such whenever possible to hopefully be easier on the whole emissions system. My commute to work is probably long enough to do a regen without issue most times.


Dr. House is what I need for sure. I just need to find the Dr. House of Cruze diesels. One of the hard things is no dealer will admit they don't have the experience with the car, or that it's too hard for them. They just say, we can't find it so there's nothing wrong. Maybe I should just politely ask if they can refer me to a dealer that may have dealt with more of these. I wouldn't even care if I had to travel a little. I think one of the things that colors my pessimism is that I have a genetic disorder it took doctors 15 years to diagnose ... I couldn't even count how many doctors I saw. I'd like to say cars are less complicated, since humans made them and the same humans should be able to fix them, but I'm starting to wonder is the CTD emissions system is more complex than the human body haha.

As far as how I track the data: Initially I was just observing this by feel, so I don't have hard data, and I'm not totally sure when it started. Regens became more obvious in the cold weather because when I came to a stop during a regen and idled, it would go into this little surgy idle, I presume to keep the exhaust temps up while it's idling as not to interrupt the cycle. It does not do this now that it's warmer out, just idles normally during a regen. The mpg drop was also very obvious since I drive the same routes repeatedly and you could see where they are way off norm when its regening. Aside from that there is the smell (mid or after regen the exhaust just has a particular smell) and, if you shut the car off during a regen, the fan stays running. I noticed that maybe twice the whole six months I first had the car, and then it started to happen much more often. And those were just the regens I interrupted. 
In January, knowing I had some issue, I bought a Scangauge II which allows you to see the data that several of the car's sensors are producing. One of them is soot load, which gives you a percentage of the maximum soot amount in the DPF it will handle before going into a regen. It also tells you miles traveled since the last regen, average amount traveled between each regen, exhaust gas temps, actual DEF level, etc. To be honest I still don't understand what sensor(s) is/are involved in the soot load calculation, but when it reaches 100, it does a regen. Most people report that theirs builds pretty fast up to 50% or so, then stabilizes, if you get on the highway, it should go down here and there. I got it because of the problem ... for one I really need to figure it out, and two, as long as it's happening I'm at constant risk of shutting the car down during a regen, so I watch it to make sure when it gets to 100, I keep driving (huge pain when it's doing it every 2-3 days or even more). But it at least saves me having a problem from shutting if off during these on top of everything else. I think even if your regen cycles are normal, it can be really handy to know when you are in regen mode, and drive accordingly ... can definitely help you avoid problems. The ScanGauge is about $160 and you just plug it into your OBD port (you do have to type in all the special gauge parameters but it's not too hard). There are a couple other similar gauge options that could be more affordable, and maybe others can weigh in there. It's a pretty neat thing to have, really interesting to observe some of the data ... not fun when it's showing a problem, but I hope I can someday get to the point it is just a fun, useful tool.


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## Barry Allen (Apr 18, 2018)

BodhiBenz1987 said:


> My EGTs seem fairly low but do go over 600 a fair bit on the highway. They always get high (700) when the car is warming up at low speed which seems weird.


Behavior of VW TDI cars is that when warming the ECU will inject some extra fuel during the exhaust cycle to where it's purposely warming the DPF. I don't know the reason why but I assume it's to get emissions functioning quickly. I think our cars do the same because I've seen some instant fuel economy figures displayed on the instrument cluster that aren't low enough to be a regen cycle but appear to be something that is warming up the DPF.


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## BodhiBenz1987 (Jan 13, 2018)

Barry Allen said:


> Behavior of VW TDI cars is that when warming the ECU will inject some extra fuel during the exhaust cycle to where it's purposely warming the DPF. I don't know the reason why but I assume it's to get emissions functioning quickly. I think our cars do the same because I've seen some instant fuel economy figures displayed on the instrument cluster that aren't low enough to be a regen cycle but appear to be something that is warming up the DPF.


That's kind of what I was thinking it might be, and I guess that would make sense. The EGTs I see on warm-up sort of look like a mini-regen, where it goes up very steadily, but instead of going all the way up to full regen temps it turns around and goes back to normal numbers.


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## resurgent cineribus (Feb 26, 2019)

BodhiBenz1987 said:


> Dr. House is what I need for sure. I just need to find the Dr. House of Cruze diesels. One of the hard things is no dealer will admit they don't have the experience with the car, or that it's too hard for them. They just say, we can't find it so there's nothing wrong. Maybe I should just politely ask if they can refer me to a dealer that may have dealt with more of these. I wouldn't even care if I had to travel a little. I think one of the things that colors my pessimism is that I have a genetic disorder it took doctors 15 years to diagnose ... I couldn't even count how many doctors I saw. I'd like to say cars are less complicated, since humans made them and the same humans should be able to fix them, but I'm starting to wonder is the CTD emissions system is more complex than the human body haha.
> 
> As far as how I track the data: Initially I was just observing this by feel, so I don't have hard data, and I'm not totally sure when it started. Regens became more obvious in the cold weather because when I came to a stop during a regen and idled, it would go into this little surgy idle, I presume to keep the exhaust temps up while it's idling as not to interrupt the cycle. It does not do this now that it's warmer out, just idles normally during a regen. The mpg drop was also very obvious since I drive the same routes repeatedly and you could see where they are way off norm when its regening. Aside from that there is the smell (mid or after regen the exhaust just has a particular smell) and, if you shut the car off during a regen, the fan stays running. I noticed that maybe twice the whole six months I first had the car, and then it started to happen much more often. And those were just the regens I interrupted.
> In January, knowing I had some issue, I bought a Scangauge II which allows you to see the data that several of the car's sensors are producing. One of them is soot load, which gives you a percentage of the maximum soot amount in the DPF it will handle before going into a regen. It also tells you miles traveled since the last regen, average amount traveled between each regen, exhaust gas temps, actual DEF level, etc. To be honest I still don't understand what sensor(s) is/are involved in the soot load calculation, but when it reaches 100, it does a regen. Most people report that theirs builds pretty fast up to 50% or so, then stabilizes, if you get on the highway, it should go down here and there. I got it because of the problem ... for one I really need to figure it out, and two, as long as it's happening I'm at constant risk of shutting the car down during a regen, so I watch it to make sure when it gets to 100, I keep driving (huge pain when it's doing it every 2-3 days or even more). But it at least saves me having a problem from shutting if off during these on top of everything else. I think even if your regen cycles are normal, it can be really handy to know when you are in regen mode, and drive accordingly ... can definitely help you avoid problems. The ScanGauge is about $160 and you just plug it into your OBD port (you do have to type in all the special gauge parameters but it's not too hard). There are a couple other similar gauge options that could be more affordable, and maybe others can weigh in there. It's a pretty neat thing to have, really interesting to observe some of the data ... not fun when it's showing a problem, but I hope I can someday get to the point it is just a fun, useful tool.



Ah, I thought maybe there was some driver menu option I hadn't discovered or something already built in. I have a cheapo OBD2 receiver that is good for pulling codes and certain sensor data and I just purchased a better bluedriver device; I'll have to see if that supports this data. I'm kind of a data junkie and have considered setting up some kind of gauge/display to keep an eye on these things. 

Yes I do think that technician is probably out there somewhere but the trouble will be finding them. I keep thinking of wasted goodwill if the manufacturer doesn't step in to make things right somehow. I know the VW TDI had/has an almost cult like following and a satisfied customer is great marketing. I talk to lot of people about my car and how much I love the thing (of course now that GM has killed the car off anyway it doesn't necessarily help them sell any more but if it were still in production I might help sell one or two for them) In the few months I've had mine I'm always keeping an eye out for the little blue TD badge and just spotted my first and only one at a Wendys by my house. OTOH I was also always pretty loyal to Ford cars but they are dead set on killing them all off. For someone uninterested in an SUV/crossover I suppose brand loyalty is up for grabs. 

Of course I'm in MI not too far from GM's engineering base and I would bet you there is some engineer sitting at a desk somewhere who knows all the ins and outs of the emissions system on this and was their baby and could diagnose it in ten minutes. I work at a specialty medical practice and our doctors can do incredible things every day like rebuilding someones spinal column so they can walk again or repair a shattered cranium so I would agree even a complicated car issue should not be unsolvable in the grand scheme of things. I would probably start making some calls/contacts with GM directly and see if anything promising turns up.


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## BodhiBenz1987 (Jan 13, 2018)

resurgent cineribus said:


> Ah, I thought maybe there was some driver menu option I hadn't discovered or something already built in. I have a cheapo OBD2 receiver that is good for pulling codes and certain sensor data and I just purchased a better bluedriver device; I'll have to see if that supports this data. I'm kind of a data junkie and have considered setting up some kind of gauge/display to keep an eye on these things.
> 
> Yes I do think that technician is probably out there somewhere but the trouble will be finding them. I keep thinking of wasted goodwill if the manufacturer doesn't step in to make things right somehow. I know the VW TDI had/has an almost cult like following and a satisfied customer is great marketing. I talk to lot of people about my car and how much I love the thing (of course now that GM has killed the car off anyway it doesn't necessarily help them sell any more but if it were still in production I might help sell one or two for them) In the few months I've had mine I'm always keeping an eye out for the little blue TD badge and just spotted my first and only one at a Wendys by my house. OTOH I was also always pretty loyal to Ford cars but they are dead set on killing them all off. For someone uninterested in an SUV/crossover I suppose brand loyalty is up for grabs.
> 
> Of course I'm in MI not too far from GM's engineering base and I would bet you there is some engineer sitting at a desk somewhere who knows all the ins and outs of the emissions system on this and was their baby and could diagnose it in ten minutes. I work at a specialty medical practice and our doctors can do incredible things every day like rebuilding someones spinal column so they can walk again or repair a shattered cranium so I would agree even a complicated car issue should not be unsolvable in the grand scheme of things. I would probably start making some calls/contacts with GM directly and see if anything promising turns up.


That's exactly what I'm thinking regarding the engineer, or engineers, sitting out there who designed this and know every inch (physical and digital) of the car. I don't think it's a poorly-designed or thrown-together car, and I'm actually impressed with how much still does work in spite of whatever isn't working (i.e. the car still runs well, gets great mpg outside the regens, and in terms of the tailpipe, is clean). But somebody who knows how it works would probably be able to drive it around, look at the data for a bit, or just hear what I'm describing, and say exactly what is wrong, or at least narrow it down. I wish I could talk to that guy! I'm not an expert on these things and am not good with computers, but I do know enough to want to know more ... I hate not knowing enough to even be able to theorize. Of course at dealerships you can't even talk to the mechanic themself which makes it harder ... you have to go through service managers, who, even if they are trying to be helpful, weren't the ones with their hands in the car.
The loyalty thing concerns me a bit with GM, at least as far as these cars go. If I had a Chevy truck I might feel differently, because I think loyalty and reputation are a big part of that brand. But maybe I'll find out otherwise if I get far enough with a customer service claim. I'm sure any car company throws around the canned unhelpful answers at first so it could be I just have to dig past those. As discouraging as this has been, I still brag about the car and enjoy telling people about it. People can't believe the mileage. And even the looks get compliments. Yesterday I volunteered at a science fair and had the car at our tent unloading, and someone walked by and said "wow, this is a nice car!" ... how often does that happen with an economy sedan? Overall the car helped give me a much more positive opinion of GM, and if their customer service came through they could salvage that.


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## Barry Allen (Apr 18, 2018)

BodhiBenz1987 said:


> The EGTs I see on warm-up sort of look like a mini-regen, where it goes up very steadily, but instead of going all the way up to full regen temps it turns around and goes back to normal numbers.


During cold weather I think the warmup of the DPF is to make sure moisture from the exhaust isn't freezing and clogging it. You want a lot of heat in there to make sure all the water that comes in the exhaust stream is flowing through there.


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## BodhiBenz1987 (Jan 13, 2018)

Barry Allen said:


> During cold weather I think the warmup of the DPF is to make sure moisture from the exhaust isn't freezing and clogging it. You want a lot of heat in there to make sure all the water that comes in the exhaust stream is flowing through there.


That definitely makes sense. Mine does it in hot weather too though. Maybe it's to ensure any condensation is eliminated, even without the threat of freezing?


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## BodhiBenz1987 (Jan 13, 2018)

So here is a question I haven't been able to find an answer to: What is the difference between "soot mass %" (or soot mass grams in Gen 1), and "DPF differential pressure" ... I thought the former was determined by the latter? I noticed my DPF differential pressure is always somewhere between 0 and 1.0 PSI (depending on throttle) whether the soot mass is at 0 or 100. I'm using the 2.8 Duramax X Gauges since the Cruze ones don't all work, so maybe the DPF diff pressure gauge is not accurate/relevant. But it makes me curious ... is pressure differential actually the only thing determining the soot % calculation, or does something else go into it too (or something totally separate)? There are basically two things that could be happening in my car: 1) the DPF is filling with soot rapidly and requiring a regen to clean it out every 100-150 miles or 2) some sensor/parameter/ECM program is confused and it's continually cleaning a practically empty DPF over and over. I feel like it would be a big step forward if I could figure out which somehow.


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## TDCruze (Sep 26, 2014)

BodhiBenz1987 said:


> That definitely makes sense. Mine does it in hot weather too though. Maybe it's to ensure any condensation is eliminated, even without the threat of freezing?


This extra heat at startup would I imagine be to light off the catalyst in the SCR faster, much like the catalytic converter in a gas engine it must be hot to work. 



BodhiBenz1987 said:


> So here is a question I haven't been able to find an answer to: What is the difference between "soot mass %" (or soot mass grams in Gen 1), and "DPF differential pressure" ... I thought the former was determined by the latter? I noticed my DPF differential pressure is always somewhere between 0 and 1.0 PSI (depending on throttle) whether the soot mass is at 0 or 100. I'm using the 2.8 Duramax X Gauges since the Cruze ones don't all work, so maybe the DPF diff pressure gauge is not accurate/relevant. But it makes me curious ... is pressure differential actually the only thing determining the soot % calculation, or does something else go into it too (or something totally separate)? There are basically two things that could be happening in my car: 1) the DPF is filling with soot rapidly and requiring a regen to clean it out every 100-150 miles or 2) some sensor/parameter/ECM program is confused and it's continually cleaning a practically empty DPF over and over. I feel like it would be a big step forward if I could figure out which somehow.


I am not sure how the ECM calculates the soot mass %, but I would imagine the DPF pressure differential would vary with engine load and RPM. 
I don't have a gauge to check my pressure differential, but I would kind of expect to see a bit more than a 0 - 1.0 psi variance. 
*edit* from what I can search online about delta P, it seems like 1.0 psi would be rather high. 

Maybe the gauge does not work for that parameter or maybe there is an issue with one of your pressure sensors? 
Hope that someone else with a scan gauge can chime in and confirm what their pressure differential readings are.
Possibly you have a pressure sensor not reading properly, but working well enough not to throw a code?


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> Maybe the gauge does not work for that parameter or maybe there is an issue with one of your pressure sensors?
> Hope that someone else with a scan gauge can chime in and confirm what their pressure differential readings are.
> Possibly you have a pressure sensor not reading properly, but working well enough not to throw a code?


I'm starting to lean towards the same thought you have, that it could be a sensor problem. I did find there is a second PID today called calculated DPF exhaust flow resistance, which seems to correlate more with the soot mass. And it reads super high on mine, from everything I can research ... 2.9 PSI when I was at 85% soot. When I reach 98% soot it went up to 3.3 PSI. At the end of a regen it said 2% soot but 2.4 PSI resistance/differential. Then as soot was building, it went down to 1.8 PSI. All weird. Again I don't know how much to reach into that not knowing if the PID is right for this car and maybe not giving me accurate info. It makes me think though, that like you said it may be a sensor issue, or a hose issue. I found one hose to the DPF diff sensor was not well connected and has a small tear at the end, and adjusted the connection as best I could. It is the larger hose though (pre DPF) so you would think a leak there would equal false low values, not high? There is also a little scrape on the smaller hose that could be a small hole, too. After I adjusted that larger hose, it made no difference on the resistance reading or soot mass climb. It went from 85 to 100 and did a regen. However in the next 29 miles the soot growth has been slower than the last two times. Not sure what to think but I am going to point out those hoses at the dealer tomorrow. If the sensor itself is OK, but the hoses are leaking or blocked, I could see that throwing false values but not a CEL, right? I can't see the hoses where they attach to the DPF itself so not sure the condition there. It seems the hoses and pipes come as one unit and not very expensive (at least not on Rock Auto). So I hope the dealer will replace those as well as the hose clamps.


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## BodhiBenz1987 (Jan 13, 2018)

Back from the dealer today with not much progress. They did check for boost leaks and said the intercooler is not leaking, so I think that is helpful to know. However their comment on the ripped diff pressure sensor hoses was that if they were leaking there would be a code. Sorry but that makes no sense to me. The sensor and system inherently involves a range of data results, meaning there is a threshold of varying values that will not be tagged as abnormal. If the leak (or blockage) were small enough, if could cause higher differential pressure results without said results being out of range. Whatever is bad, whether it's the hoses, a sensor, an ECM routine, that is what is happening. It's abnormal but the whole system functions well enough to keep it within a range that doesn't throw a code. They told me I just have to keep driving it, and if any codes come up they can replace whatever the code says. In other words, when this problem fries another major component, they can replace the component without fixing the underlying problem, so I can continue driving until it fries yet another component, and so on.
I called Chevy today and opened a case and managed to politely explain the issue and why it is a problem for me. I don't want to throw my dealer under the bus because I realize they are in a tough position and I do think they have been trying. I don't actually want them to throw random parts at it when they don't know what's wrong. But I do want someone to figure out what's wrong. It is going to dealer #2 tomorrow, and Chevy will have an advisor call me this week.


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## TDCruze (Sep 26, 2014)

BodhiBenz1987 said:


> Back from the dealer today with not much progress. They did check for boost leaks and said the intercooler is not leaking, so I think that is helpful to know. However their comment on the ripped diff pressure sensor hoses was that if they were leaking there would be a code. Sorry but that makes no sense to me. The sensor and system inherently involves a range of data results, meaning there is a threshold of varying values that will not be tagged as abnormal. If the leak (or blockage) were small enough, if could cause higher differential pressure results without said results being out of range. Whatever is bad, whether it's the hoses, a sensor, an ECM routine, that is what is happening. It's abnormal but the whole system functions well enough to keep it within a range that doesn't throw a code. They told me I just have to keep driving it, and if any codes come up they can replace whatever the code says. In other words, when this problem fries another major component, they can replace the component without fixing the underlying problem, so I can continue driving until it fries yet another component, and so on.
> I called Chevy today and opened a case and managed to politely explain the issue and why it is a problem for me. I don't want to throw my dealer under the bus because I realize they are in a tough position and I do think they have been trying. I don't actually want them to throw random parts at it when they don't know what's wrong. But I do want someone to figure out what's wrong. It is going to dealer #2 tomorrow, and Chevy will have an advisor call me this week.


Did they at least offer to repair the torn pressure sensor hoses? 

This is what I find so frustrating with automotive service work these days. Granted there are few items that don't "throw a code" anymore, it seems like nobody takes a customer complaint seriously without that magic CEL. How did cars ever get fixed before the days of CEL's?

I think it is a good idea to open a complaint and take it higher up. 
The dealer may have their hands tied with GM as far as covered warranty work, they have nothing solid to base spending further time without that "CEL". 
As in GM may not pay them for further work without "cause". 
A complaint may get some more attention and at least lets them know it is not fixed. 

Hopefully dealer #2 can figure something out!


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## Ma v e n (Oct 8, 2018)

Bohdi,
To answer your most recent question, a leaking hose on the differential pressure sensor pre-DPF would result in artificially LOW DPF pressure readings, or low soot mass readings. Now these ECMs do all kinds of rationality checks and such, and it's possible it's commanding regens because it's checking to see what's going on with readings it doesn't quite "like" but are still within spec for "good" readings. 

Same goes for EGT sensors, if the exhaust temp sensors are skewed higher than actaul temps, but still in the acceptable and rational range the car can suspend the Regen that's occuring and then restarts it when it sees favorable conditions again. This can result in multiple partial regens.

There are techs who have a better understanding and more training on diesels than others. They will have GM Master Technician Certification in Diesel Performance. This certification is NOT mandatory, and most dealerships don't have a GM Master cert'd diesel tech. You may want to ask GM customer service to direct you to a shop that has one.

GM Master cert's are optional training. They require a tech to be fully trained in GM courses beyond the mandatory standard training, they require the tech to earn ASE certified in that area. And then beyond both standard GM and ASE certs the tech has to go to a hands on assessment course where they actually have to demonstrate their skills and knowledge in the understanding and repair of the system in question. You even get a certificate! LOL


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> Did they at least offer to repair the torn pressure sensor hoses?
> 
> This is what I find so frustrating with automotive service work these days. Granted there are few items that don't "throw a code" anymore, it seems like nobody takes a customer complaint seriously without that magic CEL. How did cars ever get fixed before the days of CEL's?
> 
> ...


They did not think the hoses needed to be replaced, based on the fact they weren't leaking since there was no CEL. The more I think about that the more it bothers me in and of itself ... even if they aren't leaking, why wait until they are to replace them, when there is a visible tear? Granted it is outside the clamp as far as I can see, but it could extend further or get worse in the future. If I see a torn hose on one of my older cars I generally replace it, leaking or not.
I dropped the car at the other dealer this morning and I can at least say they certainly listened and seem to have an interest. Whether they can do anything is another story but it's a good start and maybe between that and the call I put into Chevy something will happen.


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## BodhiBenz1987 (Jan 13, 2018)

Ma v e n said:


> Bohdi,
> To answer your most recent question, a leaking hose on the differential pressure sensor pre-DPF would result in artificially LOW DPF pressure readings, or low soot mass readings. Now these ECMs do all kinds of rationality checks and such, and it's possible it's commanding regens because it's checking to see what's going on with readings it doesn't quite "like" but are still within spec for "good" readings.
> 
> Same goes for EGT sensors, if the exhaust temp sensors are skewed higher than actaul temps, but still in the acceptable and rational range the car can suspend the Regen that's occuring and then restarts it when it sees favorable conditions again. This can result in multiple partial regens.
> ...


Thanks for the info on the pressure differential. That's kind of what I was thinking so maybe the hose is not doing anything (or both are leaking and the bottom one is "winning" so to say. That's helpful to know about the certified techs. I kind of assumed every dealer would have one with the amount of trucks they handle. If this dealer can't get anywhere, maybe that is the answer, having GM direct me to a place that has a master certified diesel tech. The dealer it is at now mentioned having their diesel tech look at it, but did not specify what certification they have.


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## BodhiBenz1987 (Jan 13, 2018)

So here's the latest: Dealer today sounded like they were going to help, or try, or that they believed me, which felt hopeful. But they called at the end of the day saying they had pulled the data from the car and here's the bomb they dropped on me: according to the car's data history, it has completed 13 regens lifetime. LIFETIME. I've literally watched that many with my own two eyes in the last 2,000 miles. The soot level goes to 100, the exhaust temps go to 1200 and stay there while the soot levels go from 100 to somewhere between 4 and 2. It lasts about 10 minutes. Then the soot levels climbs to 100 again over a couple days, repeat. If that isn't a regeneration, what is it? They couldn't answer that question, of course, because it doesn't matter because their numbers are the numbers and nothing else matters.
So either what I am witnessing is incomplete or phantom regenerations of some sort, or the computer hasn't recording any of them. My guess would be the latter. He couldn't tell me when the last regeneration was, or distance since last. I would not be surprised if it was September according to his data. The soot level reading (based on differential pressure) he got was exactly what mine is (43%) and he had another number that was "estimated soot level based on other data" of some sort that was 13%, but never mind that massive disparity, apparently nothing worth looking into. Anyway, they turfed me back to the first dealer, who already said they can't do anything else. He said the first dealer has a top-rated certified diesel tech. I really don't want to go back to a dealership that has so far put the wrong oil in my car and sent me home with a massive exhaust leak. I am still awaiting my call back from GM but the service manager today told me they already went through GM and they won't do anything because the data he pulled today is the final word, my car has only done 13 lifetime regens and it is working fine. 
An interesting thing to note, which I don't know if I mentioned before, is that when my car does a regen, the PID that tells you status shows the numbers 6 while it's warming up and 7 while its regening. The options listed on the Scangauge page are numbers 1 through 5. I thought this was an SG glitch but I'm guessing it's the car's glitch now. No one will listen to any of this though; they don't care, and if they do their hands are tied by those who don't care. Now on top of the regen issue I have to wonder what else is not working ... maybe there are no codes because the computer is glitched out?


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## Ma v e n (Oct 8, 2018)

Well that sucks.

I don't know if/how the Regen counter acknowledges partial regens, I've never tried to make a Regen abort and see if the counter incremented.

The 2nd shop turning you away is kinda shady. I'm assuming you're being calm and respectful, etc when you're dealing with this new shop so I don't fully understand why they would bounce you. It sounds like they dont really believe your issue.

There used to a tool we used called a VDR, that customers could take home and they would trigger it when their problem was occuring. It really sucks that it doesn't work on the gen2 Cruze....The scan tool is how we do that now....

How often does your car regen? Do you know it's schedule or is it random? Honestly most techs, including myself don't like going on long road tests with customers, or even long road tests without them, but it sounds like you need to have the car perform a Regen(partial or otherwise) while the GM scan tool is hooked up. Ideally have them witness multiple regens if they are occurring close enough at this time.


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## BodhiBenz1987 (Jan 13, 2018)

Ma v e n said:


> Well that sucks.
> 
> I don't know if/how the Regen counter acknowledges partial regens, I've never tried to make a Regen abort and see if the counter incremented.
> 
> ...


When I went to pick up the car they did take the time to talk to me longer, both the server manager and the head service manager, and go over the data. They did actually acknowledge that there could be something wrong with the computer or data recording, or that the regens could be partial or so forth, the things I mentioned above. So at least I don't feel like I was just being dumped back on the other dealer or that they were just turning me away. I guess they felt it would make more sense for me to stay with the dealer I had been working with, since neither could figure anything out. They did not mention anything like a GM scan tool. That is part of the issue, that they can't drive it for 100s of miles and see what I am talking about (which I can understand but it is frustrating). They said there is not really anything they can do but if keep track of what I am seeing and keep a log I can bring it back after another 3 or 4 regens (or what I think are regens) and see if their data changes. They said everything else on the car looks perfect, which is encouraging but doesn't make me less worried about whatever is going on wrong. They did suggest I try always using Shell, BP, or Exxon and see if that improves. I use Wawa and Royal Farms fuels. Again though I'm suspecting it is not an actually soot issue at this point but a data one.
In the meantime I talked to someone from GM who called me back and he was very polite but seemed stumped too. He is putting me in touch with someone at the first dealer in charge of customer satisfaction and said maybe they can arrange an extended test drive. I would think I could bring it in when I see it gets to 95% soot or so and they would not need to take it long to see a regen take place. 
So now I am kind of floating between the two dealers but in each case I just have to keep driving it. I do get their dilemma. It just sucks for me.


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## Ma v e n (Oct 8, 2018)

While it's "probably" not the cause I totally concur with their recommendations to stop using Wawa fuel.

Using fuel from a name brand fuel supplier(not a name brand dairy.. ? ) preferably a high volume station is best. If you happen to have Costco near you, see if they are a TopTier diesel station.


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## BodhiBenz1987 (Jan 13, 2018)

Ma v e n said:


> While it's "probably" not the cause I totally concur with their recommendations to stop using Wawa fuel.
> 
> Using fuel from a name brand fuel supplier(not a name brand dairy.. ? ) preferably a high volume station is best. If you happen to have Costco near you, see if they are a TopTier diesel station.


The Costco near me doesn't have fuel, but I have a Shell fairly close to me. I am not super concerned about price given my mpg so if it's more expensive that's fine. I had mainly used the others for consistency since they are right on my route, and since they are high-volume diesel sellers it didn't really occur to me they would potentially have that bad fuel. I have used them since the car was new and didn't see issues then, but, I wan't tracking closely then, and could be either a cumulative thing or lower fuel quality becoming more prominent in winter fuels. Either way it's easy enough for me to switch to the name brand and stick with it and it sounds like I should do that regardless.


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## simplyrob (Jun 20, 2018)

Any new updates?


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## BodhiBenz1987 (Jan 13, 2018)

simplyrob said:


> Any new updates?


Thanks for checking in. Unfortunately basically just the same. Though I guess that's not too unfortunate, since it hasn't gotten worse or caused anything major that I know of, and it still seems to drive fine and still no codes. I've been keeping lots of notes on the soot % and regen behavior (I just carry around a notebook full of nonsense-looking scribblings in my car now!). I think I've had five regens since my last update, most around 130-150 miles but I have managed two just over 300 miles ... in both the latter cases it rocketed to 80% soot and then semi-stabilized. It actually went down like 10% (from 86 to 76) one time on the same cookie-cutter 40-mile highway drive I do 2-3 times a week, and every other time goes up ... I have no idea what made the difference ... went up again on the way home. Another weird thing, twice I've had it do a regen, go down to around 2% and then instantaneously flash to 25%. So I continue to lean towards believing there is a sensor, computer, or hose issue, or that it was not "relearned" correctly following the DPF replacement (if that is even a possibility). GM never followed through as they said, though I later discovered they had my email wrong so not the guy's fault. I opened another case (they closed my last one) because I had unanswered questions and still waiting for answers. I asked if the soot parameter(s) were possibly calibrated wrong or if that is even how it works (I had assumed it was something the ECM relearned itself) but the GM agent didn't know and was going to ask my dealer. Have not heard back in a few days. The communication is difficult because there are so many middlemen. In two weeks I'll be doing 80+ miles a day five days a week for five weeks for my summer job so that will be a test of where this is going.


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## BodhiBenz1987 (Jan 13, 2018)

Just an update on this neverending saga. The good news is the regen frequency has slowed down considerably, though it is still way under what I would expect for driving 80 miles of highway most days. The last four cycles has been over 300 miles, the most recent at 350 miles. It actually seems to stabilize at about 85-90% soot ... on the last cycle it took 80 miles to go from 94 to 100%. The only downside to this development is that now the dealer will never actually see what it's doing or believe me. They looked at the car again at the urging of GM customer service, and the tech drove it 110 miles. It had done a regen literally 7 miles before my appointment (bad luck!) so of course it did not do one again, and after their driving it showed 56% soot, so actually looked totally normal. Somewhat understandably, they just don't think it is doing regens when I say it is. It doesn't help that the data says the car has completed 19 lifetime regens. As I mentioned before, the other dealer in early May came up with 13 lifetime regens. I've seen 6 regens between that, so that actually adds up now, but on total it makes no sense with the average of 224 miles between regens showing. My theory is that when they installed the turbo and had to relearn everything, it must have reset the total regen stats for some reason. Using the mileage since then, the math is perfect between total regens and avg miles between regens. Anyhow, I can do all the math I want but I might as well be telling it to a wall, because at the end of the day the dealer can't work based on what a customer tells them from an aftermarket scanner, understandably they have to see it themselves. I'm really starting to feel insane because I know that's how I look, no matter how polite I am. Anyway, I appreciate that they looked at it again and tried to see what I'm rambling about, so I just quietly accepted the car back for now and they said to bring it back at the beginning of July when a particular service manager is back so they can finish looking at everything. In the meantime, and probably after, I can live with a regen every 300+ miles. I'd rather that than anyone do anything based on guesses as to what's wrong. I'm just the kind of person that hates not being able to solve something I know has an answer, and I want everything operating in top form ... guess I got all the engineer genes from my family even if not the knowledge.
One thing that hangs in my mind is that there is a visible tear or scratch in the smaller pressure differential hose, which I have borescope pictures of and gave the dealer the pictures when I dropped off the car. I had mentioned it before too and they said it is not leaking, because a leak would trigger a DTC. I'm inclined to believe this, because if it were leaking it would never go to 0%, and it does. Still, am I nuts for thinking if there is visible damage to a hose that is involved in a precision measurement, that hose should be replaced? Maybe what I think is a hole isn't a hole, but they haven't said that, just that is isn't a problem. They quoted me $400 to have it replaced. I don't even mind the cost but the whole DPF system seems so finicky that I kind of don't want to take chances on actually causing more problems with unnecessary "surgery".
Anyway, I'll see where it goes in July and then I guess just enjoy the car and hope the problem works itself out on its own. Even with two regen cycles during my last tank of fuel, it got 54.3 mpg for the tank, which is on par with my best tanks last summer (not counting the road trips). On a trip to NYC and back last week (260 miles) I got 63.4 mpg and hit 69.9 on my "last 50". So, it's still a great car. I just want to make it last a long time.

Edit to add: When I fiddled with the aforementioned hose and moved the clamp over the damaged spot, was just about right when it went from 150-mile cycles to 300-mile cycles ... which could entirely be a coincidence since I've been seeing inconsistency the whole time and it could be a number of other factors leading to gradual improvement. But that leads me to wonder about the hose a little more than I would otherwise.


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## oregon_rider (Jul 21, 2017)

I assume you have switched to a better quality fuel now. Yes?

Given that you may have been running crappy fuel for a while - I would run some stanadyne additive to clean and lubricate injectors. Or add a few gallons of b20 biodiesel to your tank to loosen things up.... (it both cleans and lubricates injectors/pump etc.)

After the additive has had some time to do it's magic - I would blast it down the highway at a higher rpm for a bit to clear things out....

Also, many in this thread have suggested an egr valve that isn't working well - partially clogged and sticky etc. possible not enough to throw a code, etc. Given your original post title describing a "surging idle" would support this theory...

And it may throw off your experiment - but running a diesel particulate filter cleaner additive will help. May help unclog the cat too - if it is partially plugged with soot and contributing to the problem.

jeff


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> I assume you have switched to a better quality fuel now. Yes?
> 
> Given that you may have been running crappy fuel for a while - I would run some stanadyne additive to clean and lubricate injectors. Or add a few gallons of b20 biodiesel to your tank to loosen things up.... (it both cleans and lubricates injectors/pump etc.)
> 
> ...


I'm hesitant to run additives since I haven't had it confirmed that they are 100% OK to run in these, and one dealer recommended against it. For biodiesel, isn't B5 the maximum for them? I have done 2,000 miles on top-brand fuel now so I'm having a hard time believing I would see no improvement if that were the problem. Though, I did see improvement as mentioned above ... but after I posted that I had my worst run yet, going 110 miles before the next regen, doing them back to back days ... didn't think I'd make 100 miles honestly. What's kind of coming to my mind, and someone can correct me if this is wrong, but that is a ton of soot and would take pretty serious fuel system malfunction, intake or exhaust malfunction, or oil burning to do. I would think any of those issues would have to be severe and I would not be getting 60+ mpg easily and basically running well (the only thing I can say is it occasionally still feels "boggy" but I can't put my finger on it ... it could very well just be poorly timed shifts on my part). So my inclination is that it's a sensor or calibration problem and there isn't actually that much soot? The fact it runs through a regen like butter every time makes me further wonder if it really even has much to burn off in the first place. Nonetheless I would love it if they would confirm they have looked at hte EGR valve, physically, and I have also wondered if something post or pre dpf could be clogged as you said (the cat/DPF assembly is new as of April, in case that got lost in the very long thread ... when I picked up the car with a brand new empty DPF, it said 82%, which is what it was at with the old DPF). It goes back Monday and I'm hoping I can just get some answers. I'm not asking them to train me as a tech for free but I'd love more than "it isn't throwing codes, everything looks good, nothing is wrong". I'm losing my mind so much that I've literally made Excel graphs of the soot v. miles-since-last data.


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## oregon_rider (Jul 21, 2017)

1. The vehicle is approved to run b20 - it is in the owner's manual. I just double checked...
2. Trust me - if you are not running B5 or B20, you want to run an additive every once in a while to clean and lube the injectors, pump and fprv. Ignore what the dealer said... 
3. Running something like "liqui-moly dpf protector" as an additive will help keep your dpf clean, regenerate more easily, and help clean soot from egr as well... I just got two cans of this for my daughter's car along with a can of injector cleaner. I have a scangauge 2 and will tell you what I see after running with it. 

From your long thread - my take is that the car isn't running well for some reason and is loading dpf with soot. Or you drive like you stole it and are shooting yourself in the foot... ;-) 

How is your oil level? Is it going down? e.g. consumption might be turbo going bad and leaking oil, which would, in turn, plug up DPF

jeff


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> 1. The vehicle is approved to run b20 - it is in the owner's manual. I just double checked...
> 2. Trust me - if you are not running B5 or B20, you want to run an additive every once in a while to clean and lube the injectors, pump and fprv. Ignore what the dealer said...
> 3. Running something like "liqui-moly dpf protector" as an additive will help keep your dpf clean, regenerate more easily, and help clean soot from egr as well... I just got two cans of this for my daughter's car along with a can of injector cleaner. I have a scangauge 2 and will tell you what I see after running with it.
> 
> ...


No oil consumption, checked regularly over thousands of miles and I can't see any loss. I drive on the conservative side to the point I wondered if that was the problem and have tried all styles of driving. I easily get 70 mpg on the "last 25" and even hit that on the "last 50" recently ... my mixed driving mpg is right on with where it was last summer before the issues, and maybe even better.
My concern with ignoring what the dealers say is that it could come back to bite me if they want to use it as an excuse to turn me away or not cover something. Not that they have bad intentions but they are probably beyond sick of me and neither dealer I've been to could observe any problems with the car to the point I wouldn't blame them for thinking I'm just nuts. But if this continues I anticipate bigger problems at some point and do not want to risk any warranty issue. The B20 I could try (if I can find it) since it says that in the book, and I can lean on the print in case of dispute. 
I'd be interested to hear some of your SG numbers after you've observed a while, as one of my challenges is I have very little to go on as a baseline or comparison.


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## oregon_rider (Jul 21, 2017)

I can understand a service guy being cautious about the use of additives as there a ton of them out there and some of them are definitely not recommended gm - they say to avoid anything with alcohol or a demulsifier... 

To be safe, and totally in the clear with gm, you can just use this one sold by GM... 

https://www.ebay.com/itm/NEW-OEM-GM...61009-Increases-Lubricity-Cetane/163180124229 

and instead of using amazon, you could order it from the parts counter at your local gm dealer and keep the receipt to be really safe about it...

Looking at it - it is probably made for gm by stanadyne and is probably the same thing as stanadyne performance formula - which at one time, i believe GM approved of...

My daughter is driving the car and lives 80 miles away. I will be down there in the next couple of days to drop in the two bottles of additive I have One is dpf cleaner and the other is a injector cleaner/lubricity & cetane improver. 

When I am there, I also want to program in some more of the scangauge 2 Xgauges to observe behavior. (I think some of the codes on their website are wrong - so I need to resolve)...

I will let you know what I see on soot measurement during some short drives - before and after I add the dpf cleaner/additive (contains fuel borne catalyst, cerium oxide, to reduce ignition point of soot).

For my daughters cruze, I also went to get a blendmount bsg-1000 to mount the scangauge more permanently above the mirror. Right now it is unplugged and in the glovebox. I have it there so my daughter can use it if the check engine comes on again with reduced power - she can check the soot level and also clear the code herself without going to dealer.

jeff


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## BodhiBenz1987 (Jan 13, 2018)

I will ask the dealer about the GM additive when I am there, and see if I can get it from their own parts counter. I like the idea of using one anyway, especially in the winter. I need to see if they have touch-up paint anyway since my commute is starting to beat up my spoiler a little!
I will be calling them back tomorrow to set up the rest of the check that they didn't finish last week or at least talk to the manager who was overseeing the effort, who is supposed to be back tomorrow. I'm hoping I can get them to check the data again because it should show two more regens in the 8-day span since they last had it and is currently at 98% soot at 234 miles since last regen ... I would hope those numbers validate to them what I am trying to say, even if they can't do anything about it.
The only thing that's lingering is wondering if I should get the differential pressure hoses replaced, or if that's a illogical theory I should not waste money on. I'm attaching the photos I took of what I think is damage to the lower hose and would be interested in anyone else's thoughts on whether that merits any attention at all.
Barring any possible suggestions the dealer has tomorrow, I'll probably just keep trying to use the best fuel, the right oil, unplug the Scangauge, drive it and try to forget about it because I've pretty much taken this as far as it can go until it manifests into something major. But we'll see what they say.

Edit: the more I look at my own photos, the more I'm certain that hose wouldn't be the cause ... if it were going to leak out that hole/tear, it would leak out that style of hose clamp anyway, which as far as I know is the factory clamp. Ie the pressure isn't enough to come back past the barb anyway. Would still be interested in anyone's thoughts if anyone's still reading this saga.


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## oregon_rider (Jul 21, 2017)

I have been thinking about this more. I think the previous response from maven is a good one - find a shop with a good diesel tech. 

Instead of focusing on soot levels on the gauge. Look at how the engine is running - seems to me it is running poorly and creating alot of soot - even when you are driving on the highway. Or something may be preventing it from getting the EGTs up to where they need to be.

I have a duramax diesel since 2003. Usually, if poorly running - folks will swap in a new fuel filter and check their injector balance rates, etc. Run an additive to clean things up. I think you should do the same - focus on how the engine is running and take steps to ensure that it is running cleanly.

1. Clean the EGR - Me, I would pay the tech an hour to get this done and remove the possibility.
2. Run an additive or b20 biodiesel to clean and lubricate injectors. e.g. a sticky fprv (fuel pressure relief valve will cause a "lopey idle")
3. If you do get some b20 to run - change the fuel filter after running a tank of this through "your baby". If you don't find b20, then do 3A.. ;-) 
3A. Change the fuel filter...
4. Check injector balance rates before and after running injector cleaner/b20 etc. The injector balance rates Xgauges for scangauge are listed for colorado diesel engine - hope they also work for the cruze diesel. Your problem could be one bad injector...
5. Change the air filter just for the hell of it. It's cheap and easy..
6. Beyond that - have tech check sensors that control engine function - e.g maybe clean the MAF (mass airflow sensor), etc. 

Running one tank of bad fuel will plug up the fuel filter - and it probably won't do the injectors any favors either....

I have 21k miles on the fuel filter in my daughters cruze diesel and it has been two years - so it is "time".... 

jeff


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> I have been thinking about this more. I think the previous response from maven is a good one - find a shop with a good diesel tech.
> 
> Instead of focusing on soot levels on the gauge. Look at how the engine is running - seems to me it is running poorly and creating alot of soot - even when you are driving on the highway. Or something may be preventing it from getting the EGTs up to where they need to be.
> 
> ...


Thanks for the ideas Jeff, definitely going to try the air filter since I can easily do that myself. Some of the other stuff I need to be able to go over with the dealer. Injector balance rates are good (I monitor and they have checked), fuel filter was done in March (long after issue started). If I didn't have the gauge right now or keep such a close eye on mpg I would have no idea anything was wrong with my car. In the winter it was obvious there were too many regens because of the idle bump it does to keep EGTs up during a regen, but it doesn't need to do that in summer. The two dealers both have diesel techs with top level of training and they looked over everything from the running health standpoint and both said it's perfect. Which is why I'm perplexed. I might ask to pay for the EGR cleaning ... or at least confirm they visually checked that. Looking at the state of the EGR could be informative just in itself in terms of what kind of soot its making. But it's hard to get anyone to listen, because they do have to follow their own protocol and not just anything the customer says. We'll see though, maybe if I'm paying out of pocket it would be different? Whenever the dealer gets back to me and I go back for my paperwork, I'll pick up an air filter and fuel cleaner from the parts dept. and at least do those things.


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## BodhiBenz1987 (Jan 13, 2018)

So months into this, I am still struggling with this issue. This is "tl;dr" but I wanted to vent even if no one can do anything. I've tracked (with and without the Scangauge ... I've gotten really good at recognizing these without it) 21 active regenerations since May. I have twice had an active regeneration less than 100 miles since the previous one (both around 90 miles). I've also had one go over 500 miles, and a few go between 200-300. I had one go 300 miles and the next one go 90 with absolutely cookie-cutter same driving (road, speed, weather, traffic, fuel, oil, cargo ... you name it, nothing changed). There is no doubt in my mind at this point that the car is not making excessive soot, but has a sensor or ECM problem. I purchased an AllData subscription, and along with that and some research have found when a new DPF is installed, a "DPF relearn" needs to be performed to reset the learned values to 0 for an empty DPF. I believe this was not done either time my DPF was replaced (it was replaced shortly after the first time because of a defective neck causing a substantial exhaust leak). When I dropped off the car prior to the repair the DPF soot load read 82%; when I picked it up with an empty DPF it read 82% ... I am fairly certain this means it was not properly reset and that its "zero" is dramatically off, meaning it thinks an empty DPF is 82% full, and while it is constantly trying to learn and adapt, it will always be out of whack. That is my theory and everything I read about DPF replacement in addition to the 1.6L Cruze manual would suggest not doing that reset would indeed cause this type of problem. I politely asked the dealer who did the DPF change to explain the process to me and why the car came back with that soot reading on an empty DPF, asking if they could confirm that the relearn was completed (I had asked this in June and was ignored, so I followed up yesterday). They told me they have no idea what I'm talking about and will not discuss it with me, though I am hoping I may get a call back from another service manager next week whose voicemail I was sent to. I would be interested in anyone's thoughts on whether or not my theory is a possibility.
Since that dealer will no longer communicate with me or listen to me at all, I took the car back to the other dealer asking them to pull the same set of data they did in May to compare. In May they had been more willing to work with me, and told me to come back in a couple months to see what the numbers said, so I did that, though the service manager I worked with at that time is no longer there. Yesterday, the car was at 97% soot with 118 miles since last regen when I dropped it off ... great, I thought! They'll see I'm right about the numbers I'm seeing, which I know no one has believed before because every appointment by coincidence was right after a regen and the soot didn't look so bad. I also wanted to see if my count of regens (21 since last visit) was right, and if my calculation for avg distance between was right. Last time I went the car said it had done 13 lifetime regens for an average of 201 miles between ... in 14k miles. The 13 regens was why they blew me off and said it isn't doing the regens I think it's doing, despite the hole in the math, which the tech noticed but was told to ignore. I figured out in the interim that (I have no idea why) the lifetime count must have been zeroed when the car had the turbo replaced. Any time I use the mileage since then, instead of the lifetime mileage, the math for the car's data is perfect. So I told them the numbers I'd seen and the avg I expected based on the theory that the total is only since the turbo replacement (12k miles). The numbers came back _dead-on_ what I said, and backed me up to a T. There are two numbers for soot calculation: one based on the DPF pressure differential sensor and one based on other data. The former is what triggers a regen, solely. I am not sure why the other exists but it is based on fuel consumption and other factors; i.e. this is a good ballpark of what your soot level should be based on your driving. The DPF pressure differential sensor, as I saw, was at 97%. The calculation of what it should be, based on engine data, was 31%. That speaks volumes, in my mind. The service manager brought the papers back with the 31% circled and said that is what the soot level is, ignore the 97%, and got very irritated when I told him the other number is what triggers a regen. I told him at 97% it would do a regen soon and he said I don't know that, and it doesn't work the way I'm saying (you'll never guess what happened on the drive home!). He also told me being at 97% after 118 miles was normal, because it's all based on your driving style ... it's always the answer and I can't beat it because there's no proving my driving style, it's entirely vague and subjective. The total lifetime regens showed 34, exactly in line with what I have seen since the last visit. The average distance between was 232 miles; my predication was 235. The car has 20k miles ... 20k/34 = 588 ... (20k-12k)/34 = 235. I asked why it was 232 when 20k/34 didn't equal that and he explained to me that it's because it was an averages, and averages change over time (???). So long story short, the numbers came back illustrating my concern perfectly, and they were blown off. If I can't convince someone that the car shouldn't be at 97% after 118 miles, I'll never win. The service manager told me to call back Tuesday and talk to the head service manager to see if I can talk to a diesel tech. He said both diesel techs were not there that day. I did kind of realize it was a loosing conversation and that the service manager was getting really angry, and that they were really busy that day, so I just gave up and played dumb and politely said thanks for getting the numbers, that it was helpful and I'll call back.
At this point I can't even tell myself to just forget it, the car is just quirky but works fine and I'm just overfocusing, because I do not think that is the case. For whatever reason, the failure to relearn the DPF or the damage to the DPF pressure sensor hoses, the car thinks the DPF is full when it is not even half full. I do not think this is good for the DPF or other components, and more importantly I do think it is a fire risk, to have active regenerations frequently carried out on a DPF that has not even reached "pack" level of soot (i.e., around 50%, the point at which it can start passively regenerating ... which is why I never see the soot level go down under any circumstances).
The catch is even if I find someone who will acknowledge that something is not right, the second dealer can't do anything, nor can any other dealer, because they have no knowledge of what the first dealer actually did, and the first dealer will not talk to me. From what I understand you cannot perform the relearn at this point; the DPF has to be new or just cleaned (i.e., out of the car). Otherwise you may get the opposite problem (setting a "zero" with soot present). So bottom line, this mistake is unfixable, if that is indeed the problem, without removing the DPF again. I'm not convinced the damaged hoses aren't contributing either; these can be replaced for $500 out of pocket, and the sensor relearned, but the sensor will be relearned to the current delta pressure value, which may be just taking the problem a step farther and further convoluting everything.
Needless to say, this is a comedy of errors, and I'm not laughing, at least not in a sane way. While I still don't know how it started, I have to suspect the incorrect oil was it, given the timing. I love this car. I know these have a bad reputation but mine has really done nothing wrong, other than the turbo failure which I believe is related to the whole fiasco. I don't think anything would ever have happened if I had never taken it to that dealer for an oil change, or if I had micromanaged them while they changed it. That said, over the past several months while I try to get someone to care that it's torching itself, it hasn't missed a beat. If I weren't worried about potential damage or safety, I might just shrug it off because at least I don't have to worry about the DPF clogging. Doesn't even seem to hurt my fuel economy that much; my average lifetime is 51 and I still get easy 60s on my longer commute. So for now all I can do is hope that continues.
Anyway, there's an update if anyone was curious ... or just wanted to know more about the emissions system, because I've certainly been learning a lot!


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## Barry Allen (Apr 18, 2018)

BodhiBenz1987 said:


> I'm hesitant to run additives since I haven't had it confirmed that they are 100% OK to run in these


It's advice I've read from Karmakanix (VW specialists) in Berkeley CA: Always run an additive in diesel fuel for DPF-equipped vehicles. Using a cetane booster means the fuel has better combustion characteristics and will more thoroughly burn in the cylinders, constantly reducing the soot load in the DPF. It prolongs the life of the DPF with fewer regen cycles to go through.

I have no idea whether this advice is good, but it's out there.

*Customers should know that Karmakanix advises the continuous usage of diesel additives such as Stanadyne. Aside from lubricity issues that can cause total system failure due to metal flake from failed pumps, these additives also reduce the overall amount of soot generated. This will clearly increase the service life of the Diesel Particulate Filter.*


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## BodhiBenz1987 (Jan 13, 2018)

Barry Allen said:


> It's advice I've read from Karmakanix (VW specialists) in Berkeley CA: Always run an additive in diesel fuel for DPF-equipped vehicles. Using a cetane booster means the fuel has better combustion characteristics and will more thoroughly burn in the cylinders, constantly reducing the soot load in the DPF. It prolongs the life of the DPF with fewer regen cycles to go through.
> 
> I have no idea whether this advice is good, but it's out there.
> 
> *Customers should know that Karmakanix advises the continuous usage of diesel additives such as Stanadyne. Aside from lubricity issues that can cause total system failure due to metal flake from failed pumps, these additives also reduce the overall amount of soot generated. This will clearly increase the service life of the Diesel Particulate Filter.*


Thanks, Barry ... I think using a cetane booster likely eliminates (or mitigates) the possibility of troubles from poorer fuel ... and apparently there is a lot of it out there so it's probably a good idea. At this point I am almost certain I do not have a soot load problem, though. My last post was a novel that I wouldn't even want to re-read myself, but the long and short of it is that a relearn was never performed when the new DPF was installed and as a result my differential pressure values are way out of whack. I'm also uncertain about the previously mentioned hole in the DP sensor pipes. The data pulled yesterday showed a soot load of 97% as calculated by the sensor, and a 31% load as calculated by all other engine data (not sure what exactly that includes). Between that, my superb fuel economy, drivability, very short regen durations (~5 minutes), and oil analysis, I think its actively regenerating with less than 50% actual soot load in the DPF every time, due to improperly calibrated DP sensor. So I do not think there is any variable I can change that will make a difference. I might try the additive for other reasons, one being the engine and fuel system seem healthy so why not keep them that way.


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## BodhiBenz1987 (Jan 13, 2018)

Credit where credit is due, I did actually hear back from the service lead at dealer #1 and he listened to and understood what I was asking about the relearn. He said it was unclear from the job notes if the reset was actually done, and they will take the car in next week to make sure it is calibrated right. So fingers crossed.


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## BodhiBenz1987 (Jan 13, 2018)

So it's been about a year since I started this thread. Nothing was ever resolved. The car recently did a regen after 70 miles (!!!) of highway driving. My average lifetime mileage between regens is now 220 miles.... for a car that is driven on the highway very regularly (lifetime mpg over 50). I haven't had a check engine light since the turbo blew, the fuel economy remains terrific, power is good, it's still a nice and fun car to drive. While over the summer it bounced between 100 miles between regens and 300 miles between regens, it is now consistently 100 in the winter weather, and a couple times even less. Since my usual drive is 82 miles round trip, this means I'm getting a regen almost every time I drive the car. I religiously avoid shutting it off during one, and try to stay on the highway even though it often means detouring or driving past my home. I am of the mindset that shutting it off at 1,200 degree exhaust temps and blasting 0-degree air over it is just not thermodynamically smart to do over and over, and I still think that contributed to my turbocharger's demise. If I lose another turbo I'm SOL because GM won't supply one. 
Neither dealer nor GM will listen to me, and have told me my regen cycles are normal. It depends on your driving cycle, so you can't say going 70 miles between regens is abnormal. They said everything else is normal. So there is nothing I can do.
I'm very worried going into the winter, to the point I am considering not driving it until spring, in favor of driving my older collectors cars that shouldn't be driven in winter. My one thought keeps going back to the DPF differential hoses and sensor. I have the replacement hoses (which come with a new sensor) sitting in my kitchen, but decided against installing them myself for fear of voiding my warranty. I am considering taking them to the dealer and paying out of pocket to have them installed. They quoted me $300 labor, which is actually not that bid a deal, but I am afraid of them botching things further as they have a bad track record with the car. Kind of a "be careful what you wish for" thing. It also might be a waste of money because it's just a non-expert theory that came from my own helpless attempt at figuring it out. 
My other thought is that for some reason my car is programmed differently than other Cruze TDs. I read someone saying the VW TDIs do regens at a similar rate to mine, and someone with an EcoDiesel Jeep said the same. But every witness and piece of information (including from GM) I have read indicate the Cruzes should be a longer interval. The other thing that continues to stand out is the last batch of data pulled by the dealer: DPF pressure reading indicated 97% soot, while the soot level calculated by other data (not the sensor) was 31%. That is a HUGE disparity. The dealer told me the car does a regen based on the second number, which is absolutely wrong, so I didn't get far with that.
So ... what would others do? Keep driving it as is and let it regen every day, since it's been doing what it's doing without breaking for almost a year? Find a third dealer and take it there? Follow my months-long hunch and pay to have the lines and sensor replaced? I still love the car, I just really want to be able to love it for a long time.


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## TDCruze (Sep 26, 2014)

I am not sure why you are seeing so many regens? This is likely still a calibration issue as your sensor data seems far out of correlation. It's too bad there is so little aftermarket support for the gen 2 diesel. It may be easier to get a tuner to try to relearn the DPF than GM. I don't think any company has completed a tune yet though?

If the car is driving good and mileage is still good I would hang onto it for now. Hopefully a solution will be found.

I find if I interrupt a regen when shut off, if I just restart it and idle for a minute the fan will stay off and the turbo should be cooled.


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> I am not sure why you are seeing so many regens? This is likely still a calibration issue as your sensor data seems far out of correlation. It's too bad there is so little aftermarket support for the gen 2 diesel. It may be easier to get a tuner to try to relearn the DPF than GM. I don't think any company has completed a tune yet though?
> 
> If the car is driving good and mileage is still good I would hang onto it for now. Hopefully a solution will be found.


I just realized I never actually followed up on my previous post before the one today ... the dealer did actually do a DPF relearn about three months ago, but it did not help. It didn't hurt either. From what I've read since, the DPF and sensor should eventually relearn themselves after a certain amount of driving (like other parameters do). So I'm thinking it has to be a bad component, whether a sensor, a hose, or I hate to say it, but the ECM. I kind of doubt it would be the latter because everything else works so well. But, I know what you mean about the aftermarket. With a lot of miles left on my warranty, I'd hesitate to do anything, but it would really help to get an outside opinion from someone who is really expert at these systems. I'm trying to learn but I just don't understand it. I'm never going to get straight answers from GM because they're basically programmed to say it's normal unless a CEL comes on. To be fair, if they can't figure it out I don't want them just guessing and tearing stuff up, but I don't think they know what to look for. When they have tried to consult tech support, instead of being given support they are told to say it's normal and send me packing. If these cars had been around longer I bet there would be an outside expert who could figure it out easily.


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## MRO1791 (Sep 2, 2016)

BodhiBenz1987 said:


> I just realized I never actually followed up on my previous post before the one today ... the dealer did actually do a DPF relearn about three months ago, but it did not help. It didn't hurt either. From what I've read since, the DPF and sensor should eventually relearn themselves after a certain amount of driving (like other parameters do). So I'm thinking it has to be a bad component, whether a sensor, a hose, or I hate to say it, but the ECM. I kind of doubt it would be the latter because everything else works so well. But, I know what you mean about the aftermarket. With a lot of miles left on my warranty, I'd hesitate to do anything, but it would really help to get an outside opinion from someone who is really expert at these systems. I'm trying to learn but I just don't understand it. I'm never going to get straight answers from GM because they're basically programmed to say it's normal unless a CEL comes on. To be fair, if they can't figure it out I don't want them just guessing and tearing stuff up, but I don't think they know what to look for. When they have tried to consult tech support, instead of being given support they are told to say it's normal and send me packing. If these cars had been around longer I bet there would be an outside expert who could figure it out easily.


GM has been telling me it is "normal" for my radio to "not work well with Android", when the car was marketed and sold to be compatible with android auto... all to delay the inevitable need to replace a clearly faulty and glitch ridden radio on one of my cars. There is a long thread here on the 7" MyLink radio and its many problems. 

So, to get the "its normal" crap line about your frequent regens is par for the course. GM is really trying hard to make sure I look at every OTHER option next time I purchase a new car. 

As to your regens, it is most certainly not normal. I have three Gen 2 Diesels, and none do regens that often, and I do LESS highway driving percentage than you, and average about 44MPG (even the 2.0 Gen 1 gets about 400 miles on average for a Regen). With that said, I do see a pretty significant difference in my 3 cars, where the manual 2018 regens between 200 and 500 miles, and my auto 2017 is between 500 and 700 miles. The manual also on occasion has done a regen with only about 100 miles... I have limited data on the other auto 2018, as I infrequently drive it, but last I checked it was similar to the auto 2017, so it seems the manual doesn't get the longer intervals, perhaps due to a higher final drive ratio, and maybe less ability to fine tune drive ratios with only 6 gears, vs. 9, just a guess, but I do see it. 

Now, your's is also a manual, so there is that to consider. 

I'd drive it if I were you, what if find interesting is you regens must be short, because your MPG is not taking a big hit. I see a very big dip in MPG when there is a Regen involved. 

I would also say I don't see any harm in replacement of the DPF pressure sensor and lines, you do have the history of incorrect oil, but if I recall correctly you got a new DPF after that incident, so it should not be a factor at this point.


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> GM has been telling me it is "normal" for my radio to "not work well with Android", when the car was marketed and sold to be compatible with android auto... all to delay the inevitable need to replace a clearly faulty and glitch ridden radio on one of my cars. There is a long thread here on the 7" MyLink radio and its many problems.
> 
> So, to get the "its normal" crap line about your frequent regens is par for the course. GM is really trying hard to make sure I look at every OTHER option next time I purchase a new car.
> 
> ...


Thanks for the input on the data you're seeing. I might start another thread at some point to create a survey of everyone who has tracked regens in one place. The lack of samples to compare it to is a challenge ... not only are there few of them out there, but not that many people use a SG or TorquePro to know exactly when they're regening. Mine are pretty quick, it seems. It will go down to around 15% in five minutes and then usually slow down the rest of the way, but it usually finishes within 10 minutes. I see a huge drop in MPG on the economy screen, but it lasts for "three bars", about nine miles or less. I do wonder if over the long run my mpg gains some back from the DPF being pretty much always empty. If it is in fact a sensor error, I don't think it ever fills to even 50% soot in actuality. That would also explain why it almost never passively regenerates (i.e. the soot % climbs at varying rates but very rarely drops ... if it does it's usually 1% while engine braking, and at a high % to begin with), since if I understand correctly they do not start to passively burn off soot until packed at about 50%. 
I did get a new DPF in April, so I don't think at this point the oil is the cause. Unless the effects somehow reached the diff sensor lines ... if ash got into them it could throw off the reading ... or for that matter if oil got into the top line, it would create a higher pressure reading on top due to the liquid and a higher differential. I'd think either would eventually throw a code though. I did try to pull the hoses off to inspect, but they would not budge, so I didn't try to force them at all, of course. Part of me just wants to have it done as a rule out, with the chance it could help. My biggest concern is that it involves removing a few things in the way, and sort of like elective surgery, I have to ask, is it worth disturbing parts that could cause bigger problems? Maybe I'll drive it through Christmas and see what it does, and when things quiet down around New Years, use that time to get the lines done.


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## MRO1791 (Sep 2, 2016)

BodhiBenz1987 said:


> Thanks for the input on the data you're seeing. I might start another thread at some point to create a survey of everyone who has tracked regens in one place. The lack of samples to compare it to is a challenge ... not only are there few of them out there, but not that many people use a SG or TorquePro to know exactly when they're regening. Mine are pretty quick, it seems. It will go down to around 15% in five minutes and then usually slow down the rest of the way, but it usually finishes within 10 minutes. I see a huge drop in MPG on the economy screen, but it lasts for "three bars", about nine miles or less. I do wonder if over the long run my mpg gains some back from the DPF being pretty much always empty. If it is in fact a sensor error, I don't think it ever fills to even 50% soot in actuality. That would also explain why it almost never passively regenerates (i.e. the soot % climbs at varying rates but very rarely drops ... if it does it's usually 1% while engine braking, and at a high % to begin with), since if I understand correctly they do not start to passively burn off soot until packed at about 50%.
> I did get a new DPF in April, so I don't think at this point the oil is the cause. Unless the effects somehow reached the diff sensor lines ... if ash got into them it could throw off the reading ... or for that matter if oil got into the top line, it would create a higher pressure reading on top due to the liquid and a higher differential. I'd think either would eventually throw a code though. I did try to pull the hoses off to inspect, but they would not budge, so I didn't try to force them at all, of course. Part of me just wants to have it done as a rule out, with the chance it could help. My biggest concern is that it involves removing a few things in the way, and sort of like elective surgery, I have to ask, is it worth disturbing parts that could cause bigger problems? Maybe I'll drive it through Christmas and see what it does, and when things quiet down around New Years, use that time to get the lines done.





BodhiBenz1987 said:


> Thanks for the input on the data you're seeing. I might start another thread at some point to create a survey of everyone who has tracked regens in one place. The lack of samples to compare it to is a challenge ... not only are there few of them out there, but not that many people use a SG or TorquePro to know exactly when they're regening. Mine are pretty quick, it seems. It will go down to around 15% in five minutes and then usually slow down the rest of the way, but it usually finishes within 10 minutes. I see a huge drop in MPG on the economy screen, but it lasts for "three bars", about nine miles or less. I do wonder if over the long run my mpg gains some back from the DPF being pretty much always empty. If it is in fact a sensor error, I don't think it ever fills to even 50% soot in actuality. That would also explain why it almost never passively regenerates (i.e. the soot % climbs at varying rates but very rarely drops ... if it does it's usually 1% while engine braking, and at a high % to begin with), since if I understand correctly they do not start to passively burn off soot until packed at about 50%.
> I did get a new DPF in April, so I don't think at this point the oil is the cause. Unless the effects somehow reached the diff sensor lines ... if ash got into them it could throw off the reading ... or for that matter if oil got into the top line, it would create a higher pressure reading on top due to the liquid and a higher differential. I'd think either would eventually throw a code though. I did try to pull the hoses off to inspect, but they would not budge, so I didn't try to force them at all, of course. Part of me just wants to have it done as a rule out, with the chance it could help. My biggest concern is that it involves removing a few things in the way, and sort of like elective surgery, I have to ask, is it worth disturbing parts that could cause bigger problems? Maybe I'll drive it through Christmas and see what it does, and when things quiet down around New Years, use that time to get the lines done.


Just had another thought... EGR. All 3 of mine have now had the P2457 code for EGR cooler performance.. and one has been replaced, with completely new part number from the old EGR, next up the manual will get the new EGR cooler.. and it took about 5 months to get the part the first time, apparently it has been on national backorder (no doubt high demand due to issues).. so I have to assume there was a design change in the EGR cooler, it is possible that you have some issue with EGR, and that it isn't quite tripping a MIL, but is contributing to soot.... it's a long shot, but thought I'd put that out there.. Also, to clarify, are you saying your's goes into regen at soot levels around 50%? 10 minutes is pretty fast, mine go for between 10 and 15 minutes or so, and the Gen 1 does about 20 minutes for a regen cycle. Now if you are steady and flat highway driving for the entire 10 minutes, that would seem normal. Mine go a bit longer as the regen pauses with a downhills, or uphills, it's not flat in western WA. It is normal for the soot level to drop fast at regen start, and go slow for the last 15%, all mine do that, and in contrast the build up is just the opposite, goes fast up to 50% and gets slower and slower up to 100%.


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> Just had another thought... EGR. All 3 of mine have now had the P2457 code for EGR cooler performance.. and one has been replaced, with completely new part number from the old EGR, next up the manual will get the new EGR cooler.. and it took about 5 months to get the part the first time, apparently it has been on national backorder (no doubt high demand due to issues).. so I have to assume there was a design change in the EGR cooler, it is possible that you have some issue with EGR, and that it isn't quite tripping a MIL, but is contributing to soot.... it's a long shot, but thought I'd put that out there.. Also, to clarify, are you saying your's goes into regen at soot levels around 50%? 10 minutes is pretty fast, mine go for between 10 and 15 minutes or so, and the Gen 1 does about 20 minutes for a regen cycle. Now if you are steady and flat highway driving for the entire 10 minutes, that would seem normal. Mine go a bit longer as the regen pauses with a downhills, or uphills, it's not flat in western WA. It is normal for the soot level to drop fast at regen start, and go slow for the last 15%, all mine do that, and in contrast the build up is just the opposite, goes fast up to 50% and gets slower and slower up to 100%.


Sorry, I was a little unclear there ... they do start at 100%, not 50%, but I am wondering if the actual soot load is under 50%, with a falsey high reading telling the computer it is at 100% and thus triggering a regen. If that makes sense. I am usually on the highway for the regens, they seem to go around 10 minutes whether it is all flat steady, or a little slowing and speeding up ... even in slightly mixed driving they only take around 10 minutes. I did have one take maybe 15 minutes when I was stuck in traffic. So maybe my regen length and behavior within a regen itself is fairly normal/healthy. My build-up is not by all accounts ... I actually made some graphs a few months ago and they told a story. I do see it slow down when it gets higher, but usually in the 80s or 90s, and sometimes not at all. There have been one or two intervals where it did slow down around 60 or 70 ... those were the small handful where I ended up going 300 miles between. There was one interval where it went 100 miles between 98% and 100%. The other wacky thing it has done a couple times, is climb to about 4% and than instantaneously jump to 20-something%. I have thought of the EGR, and have also considered taking it out to inspect and potentially clean. Or even replace it myself since the EGR itself isn't expensive. It doesn't sound too hard but I second-guess myself. The dealers have said the EGR was fine but I doubt they physically inspected it (and back to the whole "everything is normal" routine for them). I have a hard time believing the car would get such great fuel economy under any condition that's producing such extremely high soot, but then again, I never know what to believe with these cars. It may be that a fairly small soot increase gets amplified, enough to put the emission stuff in overdrive but not effect economy or performance.


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## MRO1791 (Sep 2, 2016)

Ok, just had a Regen on my drive home in the manual 2018. It was almost exactly 10 minutes. At 242 miles. Lifetime average regen interval is about 400 miles. 22647 miles, 51 regens. 

One other thought. Apparently the dealership found a bad injector, I never saw a code for that, just the P2457 for EGR, but they saw something and I'm sure they wouldn't replace it otherwise. It's apparently now in stock and will get replaced with the EGR cooler when they get the last couple of gaskets for that job. I've not seen a problem with the car despite a supposedly bad injector, but it seems it could be possible misbehaving injectors could lead to excessive soot, but one would expect low MPG from that unburned fuel. It's a perplexing problem for sure.


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> Ok, just had a Regen on my drive home in the manual 2018. It was almost exactly 10 minutes. At 242 miles. Lifetime average regen interval is about 400 miles. 22647 miles, 51 regens.
> 
> One other thought. Apparently the dealership found a bad injector, I never saw a code for that, just the P2457 for EGR, but they saw something and I'm sure they wouldn't replace it otherwise. It's apparently now in stock and will get replaced with the EGR cooler when they get the last couple of gaskets for that job. I've not seen a problem with the car despite a supposedly bad injector, but it seems it could be possible misbehaving injectors could lead to excessive soot, but one would expect low MPG from that unburned fuel. It's a perplexing problem for sure.


Can I ask what you're using to track them that allows you to see total number of regens? I use the ScanGauge which is great but doesn't have an X Gauge for that for Gen 2. I've had the dealer pull that number a couple of times. That was one thing that doomed me, because when I took the car in at 14k to have them look it over, it said it had done 13 total regens. But with an average distance between of 220 or so. So they never believed me from the start it was even doing the regens. I've had the number pulled twice since and it was consistently spot-on with what I had counted in the time between. So I think that number somehow got wiped when they did the turbo repair (mathematically where the avg/total match). I was thinking of taking it in to the dealer to have them pull that number again but if I can do it on my own, that's a plus. I haven't had it checked since they did the DPF relearn a couple months ago, and I'm actually curious if that zeroed it again. I believe I was at 34 lifetime last time it was checked, which should have been an average interval of around 550 miles ... yet my average was again around 220. GM will not question that math, and the lifetime number is big ammo for them to dismiss my concerns. It's really been a perfect storm of ridiculous happenstances that make it impossible to figure out or get help ... and even makes me question myself. The only thing that proves what I'm observing is about 500 photos (and a few videos) from an aftermarket gauge, and the fact that what I've recorded from it is completely consistent with the changes in the GM-pulled data since March. Though honestly I think the last batch of data pulled from the dealer speaks for itself that something is awry ... the other dealer (not the one that pulled the data) did say they thought something wasn't right with those numbers, but there was also nothing indicating why the numbers were that way so they couldn't really do anything other than try the relearn.
The injectors had crossed my mind too. Or a possible boost leak. I would think either of those things would be pretty obvious for the dealer to find. Though I think with an injector, it could certainly be only under specific conditions that aren't present when they're testing what they test. The only thing I can tell myself there is that I would imagine over the course of a year, that would have gotten worse, or manifested in other problems.


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## MRO1791 (Sep 2, 2016)

BodhiBenz1987 said:


> Can I ask what you're using to track them that allows you to see total number of regens? I use the ScanGauge which is great but doesn't have an X Gauge for that for Gen 2. I've had the dealer pull that number a couple of times. That was one thing that doomed me, because when I took the car in at 14k to have them look it over, it said it had done 13 total regens. But with an average distance between of 220 or so. So they never believed me from the start it was even doing the regens. I've had the number pulled twice since and it was consistently spot-on with what I had counted in the time between. So I think that number somehow got wiped when they did the turbo repair (mathematically where the avg/total match). I was thinking of taking it in to the dealer to have them pull that number again but if I can do it on my own, that's a plus. I haven't had it checked since they did the DPF relearn a couple months ago, and I'm actually curious if that zeroed it again. I believe I was at 34 lifetime last time it was checked, which should have been an average interval of around 550 miles ... yet my average was again around 220. GM will not question that math, and the lifetime number is big ammo for them to dismiss my concerns. It's really been a perfect storm of ridiculous happenstances that make it impossible to figure out or get help ... and even makes me question myself. The only thing that proves what I'm observing is about 500 photos (and a few videos) from an aftermarket gauge, and the fact that what I've recorded from it is completely consistent with the changes in the GM-pulled data since March. Though honestly I think the last batch of data pulled from the dealer speaks for itself that something is awry ... the other dealer (not the one that pulled the data) did say they thought something wasn't right with those numbers, but there was also nothing indicating why the numbers were that way so they couldn't really do anything other than try the relearn.
> The injectors had crossed my mind too. Or a possible boost leak. I would think either of those things would be pretty obvious for the dealer to find. Though I think with an injector, it could certainly be only under specific conditions that aren't present when they're testing what they test. The only thing I can tell myself there is that I would imagine over the course of a year, that would have gotten worse, or manifested in other problems.


I use the Torque App on my android phone, with the Snipesy BiScan for GM plug in, along with an OBD 2 LX adapter. I did get the scanguage 2 for my Gen 1, but it's actually still in the box, never used. The Snipesy app, BiScan for GM provides much more information and it allows me to do commanded Service and Normal Regens, sensor resets, etc. I got the app for free, as I was a Beta tester when Snipesy was creating BiScan. It doesn't have a full list for the 1.6L, but it's basically the same as the 2.8L Duramax, so I use those PIDs and it gives me so many parameters I can't fit them all on my phone's screen.


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> I use the Torque App on my android phone, with the Snipesy BiScan for GM plug in, along with an OBD 2 LX adapter. I did get the scanguage 2 for my Gen 1, but it's actually still in the box, never used. The Snipesy app, BiScan for GM provides much more information and it allows me to do commanded Service and Normal Regens, sensor resets, etc. I got the app for free, as I was a Beta tester when Snipesy was creating BiScan. It doesn't have a full list for the 1.6L, but it's basically the same as the 2.8L Duramax, so I use those PIDs and it gives me so many parameters I can't fit them all on my phone's screen.


Thanks. I may invest in that as a Christmas present for my Cruze. For monitoring I really like the SG format, size, and screen, but it would be nice to have the additional options available to me. Being able to command a regen would be helpful too, because it's really frustrating to be two miles from my house and have one start, at the end of a 40-mile drive where it had all that highway it could have done it.


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## MRO1791 (Sep 2, 2016)

BodhiBenz1987 said:


> Thanks. I may invest in that as a Christmas present for my Cruze. For monitoring I really like the SG format, size, and screen, but it would be nice to have the additional options available to me. Being able to command a regen would be helpful too, because it's really frustrating to be two miles from my house and have one start, at the end of a 40-mile drive where it had all that highway it could have done it.


I'll try to post a picture of my set up. A decent phone/vent mount, USB cord and clip. Also works for Android Auto, and can run both at the same time. Actually last night when I had that Regen, I was at 99%, and 14 minutes from home, so I commanded it on, precisely to ensure it would complete before I got home, you are correct, that is a very nice feature.


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## TDCruze (Sep 26, 2014)

MRO1791 said:


> I use the Torque App on my android phone, with the Snipesy BiScan for GM plug in, along with an OBD 2 LX adapter.


I am also interested in this setup, sounds like it could be real handy. 

Would you recommend getting the OBD2 Link LX as you now have or upgrading to the OBD2 Link MX+ ?


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## BodhiBenz1987 (Jan 13, 2018)

So I finally caved and paid the dealer to install the new sensor and hoses, about $350 labor. I had them give me back the old hoses and I did find there is a serious hole in the old lower hose. Which gave me hope the new hoses would fix the issue. Nope! The car did a regeneration later in the day after I got it back and then just did another one, 100 miles later. That was pretty much my last hope and I have to assume at this point the car actually creates that much soot, or has some odd software issue. I'd ignore it because the car seems to survive constantly torching itself, but honestly I'm just about done. The car is polluting way more than it should which makes me feel lousy, it's wearing out expensive components far faster than it should, and no matter what GM tries to say, driving during a regen is unpleasant (performance, smell, mpg) so it sucks to have one happen every other day (or multiple times a day if I ever dare take a trip). I hate to say it but at this point I can only hope it fries another turbo and GM won't be able to replace it and will buy the car back. I can't in good conscience sell what I know is an unfixable lemon for full value even though I know a lot of people wouldn't really notice the problem or maybe even care. I might consider selling it in spring/summer with full disclosure if I have the energy and continue to feel this negatively about the car, but we'll see.
Meanwhile for $350 the dealer put the sensor in crooked, left a wire clip just hanging loose, and didn't rotate my tires like I asked them to.
I guess on the positive side my nagging theory is finally laid to rest and there's not really anything I can do anymore. And I wasn't wrong about there being a hole in that hose, even though it wasn't apparently affecting anything.


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## TDCruze (Sep 26, 2014)

I received an Emissions Recall notice from GM regarding frequent regens and the lack of a CEL. Maybe this reflash when available will help find the cause of your issue?


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## BodhiBenz1987 (Jan 13, 2018)

TDCruze said:


> I received an Emissions Recall notice from GM regarding frequent regens and the lack of a CEL. Maybe this reflash when available will help find the cause of your issue?


That's definitely interesting, because I heard someone mention that for a 2019 ... if you got one for a 2018 I would assume I'll get one soon. Even though I generally worry about recalls involving a reflash, at this point I am interested to see if this either helps, or at least sets up the car to throw a CEL that would encourage the dealers to look into the issue more seriously. Part of my problem has been the lack of CELs, because without one neither the dealers nor GM believe me when I say the amount of regens is excessive. I'll keep an eye on my recall status.
Edit: just checked again and it's saying no recalls on my car. Maybe it is rolling out gradually. The other person who had one said the recall software wasn't ready but they would be notified when it was ... was that what yours said as well?


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## TDCruze (Sep 26, 2014)

BodhiBenz1987 said:


> That's definitely interesting, because I heard someone mention that for a 2019 ... if you got one for a 2018 I would assume I'll get one soon. Even though I generally worry about recalls involving a reflash, at this point I am interested to see if this either helps, or at least sets up the car to throw a CEL that would encourage the dealers to look into the issue more seriously. Part of my problem has been the lack of CELs, because without one neither the dealers nor GM believe me when I say the amount of regens is excessive. I'll keep an eye on my recall status.


This was GM Canada, so maybe GM in the US is a bit behind. I can only figure that GM has become aware of a widespread issue regarding frequent regens, despite your dealers apparent ignorance of the problem. 

It stated that a reflash was not ready yet, but coming soon. Not sure if the reflash will change much, but even just getting a CEL will give you a much better chance of getting your car fixed at the dealer.


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## Carminooch (Mar 23, 2018)

BodhiBenz1987 said:


> That's definitely interesting, because I heard someone mention that for a 2019 ... if you got one for a 2018 I would assume I'll get one soon. Even though I generally worry about recalls involving a reflash, at this point I am interested to see if this either helps, or at least sets up the car to throw a CEL that would encourage the dealers to look into the issue more seriously. Part of my problem has been the lack of CELs, because without one neither the dealers nor GM believe me when I say the amount of regens is excessive. I'll keep an eye on my recall status.
> Edit: just checked again and it's saying no recalls on my car. Maybe it is rolling out gradually. The other person who had one said the recall software wasn't ready but they would be notified when it was ... was that what yours said as well?


My car has been misfiring and bucking for the first 2 minutes of driving for the last 15,000 miles. Five trips to the dealer and an accumulated month and a half of the car being in the shop, their “hands are tied because there’s no CEL”

I’ve felt the car try to shake itself to pieces and never saw a check engine light. It makes me question what would even cause that light to go on, if full on misfire and bucking wont do it then nothing will

GM has really gone downhill. Both in build quality and skilled technicians. All work I’ve had performed has been sloppy, half a$$ed, or they’re befuddled because the dummy light doesn’t show itself.

What ever happened to the days of a freeze frame capture and real diagnostics?


Sent from my iPhone using Tapatalk


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## BodhiBenz1987 (Jan 13, 2018)

Carminooch said:


> My car has been misfiring and bucking for the first 2 minutes of driving for the last 15,000 miles. Five trips to the dealer and an accumulated month and a half of the car being in the shop, their “hands are tied because there’s no CEL”
> 
> I’ve felt the car try to shake itself to pieces and never saw a check engine light. It makes me question what would even cause that light to go on, if full on misfire and bucking wont do it then nothing will
> 
> ...


That's awful you have to deal with that. This is why I have moments like my last post where I just say I wish they would buy it back. I love the car. I love telling people about it and bragging about the fuel mileage. Fit and finish aside I love its looks and feel. It's the only car I've ever ordered new and the first car I bought new on my own. When I calm down and think about it, the regens aren't even totally unlivable. But I also know if the problem worsens, I'm likely going to be left high and dry, or, if the car develops an unrelated problem, I'll likely be left high and dry about that too. I have seen a few stories about flywheels, clutch slaves, etc, that were improperly diagnosed or where they had difficulty getting it diagnosed. I can imagine if my flywheel goes, even if it sounds like steel marbles in a blender, they will tell me its normal and there are no CELs. In many ways I can't blame the dealer ... they looked at the car more than once, and couldn't find anything wrong. But they never tell you what they looked at ... did they actually physically check the EGR? Did they test the injectors? Did they check anything? Or did they just scan it for codes and say, well, the EGR and injectors, etc are all fine because there are no CELs or pending codes for those things. Obviously those parts can be bad without a code at all. Oh, and add to that if they ever manage to find something wrong (whether this issue or another), I'll be driving a rental spec loaner for three months while they (maybe) get the parts. I really want to be positive and tell myself to keep the car and not give up hope, but I feel I have zero support on it, now or ever. It feels like GM is mad anyone owns their products, diesel or not. And the complex programming stuff is above what I'm capable of learning (and likely can't do anyway because of things being locked and all the EPA-related complexity), so I can't even take charge and work on it myself. 
For what it's worth, I know there are great dealers out there, and great mechanics at dealers. But I wouldn't know how to find the right one. Or it could be the mechanics at my dealers are great, but their hands are tied by the way the cars are designed and the way GM does things. Throw in fears of the EPA that limit GM and everyone is really in a corner.


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## ChrisH80 (Feb 6, 2020)

BodhiBenz1987 said:


> That's awful you have to deal with that. This is why I have moments like my last post where I just say I wish they would buy it back. I love the car. I love telling people about it and bragging about the fuel mileage. Fit and finish aside I love its looks and feel. It's the only car I've ever ordered new and the first car I bought new on my own. When I calm down and think about it, the regens aren't even totally unlivable. But I also know if the problem worsens, I'm likely going to be left high and dry, or, if the car develops an unrelated problem, I'll likely be left high and dry about that too. I have seen a few stories about flywheels, clutch slaves, etc, that were improperly diagnosed or where they had difficulty getting it diagnosed. I can imagine if my flywheel goes, even if it sounds like steel marbles in a blender, they will tell me its normal and there are no CELs. In many ways I can't blame the dealer ... they looked at the car more than once, and couldn't find anything wrong. But they never tell you what they looked at ... did they actually physically check the EGR? Did they test the injectors? Did they check anything? Or did they just scan it for codes and say, well, the EGR and injectors, etc are all fine because there are no CELs or pending codes for those things. Obviously those parts can be bad without a code at all. Oh, and add to that if they ever manage to find something wrong (whether this issue or another), I'll be driving a rental spec loaner for three months while they (maybe) get the parts. I really want to be positive and tell myself to keep the car and not give up hope, but I feel I have zero support on it, now or ever. It feels like GM is mad anyone owns their products, diesel or not. And the complex programming stuff is above what I'm capable of learning (and likely can't do anyway because of things being locked and all the EPA-related complexity), so I can't even take charge and work on it myself.
> For what it's worth, I know there are great dealers out there, and great mechanics at dealers. But I wouldn't know how to find the right one. Or it could be the mechanics at my dealers are great, but their hands are tied by the way the cars are designed and the way GM does things. Throw in fears of the EPA that limit GM and everyone is really in a corner.


See my recall thread. Your engine is probably experimenting this precise ECU issue.


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## BodhiBenz1987 (Jan 13, 2018)

ChrisH80 said:


> See my recall thread. Your engine is probably experimenting this precise ECU issue.


Thanks for checking in on this, I received the recall notice this morning and glad to see someone already started a thread. I'm curious, but also concerned, how this will effect me. I'll chime in in the recall thread too. The thing is, I don't think this would fix the actual regen issue, it would just mean I would get a CEL for the issue. Which the dealer may still not know how to fix. So I'm torn because I run the risk of now having a car with a CEL the dealer can't fix. But maybe that's just how it goes. It's also possible they'll fix it right away once it throws a CEL ... because I don't think they've ever believed me that it was happening. I guess we'll see but it sure is interesting that this came up as a problem recognized by the factory after a year of being dismissed by dealers saying there's no way there's a problem without a CEL.


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## MRO1791 (Sep 2, 2016)

BodhiBenz1987 said:


> Thanks for checking in on this, I received the recall notice this morning and glad to see someone already started a thread. I'm curious, but also concerned, how this will effect me. I'll chime in in the recall thread too. The thing is, I don't think this would fix the actual regen issue, it would just mean I would get a CEL for the issue. Which the dealer may still not know how to fix. So I'm torn because I run the risk of now having a car with a CEL the dealer can't fix. But maybe that's just how it goes. It's also possible they'll fix it right away once it throws a CEL ... because I don't think they've ever believed me that it was happening. I guess we'll see but it sure is interesting that this came up as a problem recognized by the factory after a year of being dismissed by dealers saying there's no way there's a problem without a CEL.


I had it done on my 2018 Manual today, the other 2018 will get it eventually... Oddly it's not listed as being applicable to the 2017... Oh, after recall, my distance since last regen is my ODO reading, but sill 55 Regens, about 23K miles total. I would say get it done, if it mean you get the MIL, then they will have to figure it out, and in the end that is what you want.


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## ChrisH80 (Feb 6, 2020)

MRO1791 said:


> I had it done on my 2018 Manual today, the other 2018 will get it eventually... Oddly it's not listed as being applicable to the 2017... Oh, after recall, my distance since last regen is my ODO reading, but sill 55 Regens, about 23K miles total. I would say get it done, if it mean you get the MIL, then they will have to figure it out, and in the end that is what you want.


I agree, if he gets it done he will now have an official trail of codes.


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> I had it done on my 2018 Manual today, the other 2018 will get it eventually... Oddly it's not listed as being applicable to the 2017... Oh, after recall, my distance since last regen is my ODO reading, but sill 55 Regens, about 23K miles total. I would say get it done, if it mean you get the MIL, then they will have to figure it out, and in the end that is what you want.


I think you are right. If I end up in another Malibu for months at least it is transportation and hopefully I get the car back functioning the way I want it. I'm worried they'll just parts cannon it because they don't seem to have an idea about these cars, but if the parts cannon hits the target eventually, I guess that is better than nothing. I'm also considering trying a third dealer and maybe they'll be better? On the other hand the history I have with my regular dealer may be helpful.
As I said elsewhere, it could also just change nothing, in which case it will still be an annoying behavior, but I could assume my regen rate isn't in whatever is considered to be the damaging or concerning range. GM obviously has a real idea of what is normal, acceptable, and worrying (three different things), but the only one of those three that dealers know how to say is "normal" for everything! 
Thanks for the feedback on your recall ... I'm guessing the distance since regen will reset when you get a regen.


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## BodhiBenz1987 (Jan 13, 2018)

Appointment made for Monday ... we'll see ...


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## MRO1791 (Sep 2, 2016)

I had my first post recall regen yesterday, and not the miles are reset to a reasonable number. Regen seemed typical, and soot/miles behavior post regen also typical. 

So far so good with the recall.


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> I had my first post recall regen yesterday, and not the miles are reset to a reasonable number. Regen seemed typical, and soot/miles behavior post regen also typical.
> 
> So far so good with the recall.


Thanks for the update, it is encouraging to know at least it doesn't seem to have any unexpected side effects.


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## BodhiBenz1987 (Jan 13, 2018)

As I posted in the recall thread, I had the recall carried out yesterday. Not surprisingly it hasn't done anything so far. I was at 92% soot when the car when in, same when I came out (I did expect that), and I drove it 60 miles to see what would happen. Went into regen after a handful of miles, did the same BS of building soot like a maniac over 60 miles of all highway 60-75 mph. Now at 62%/69 miles. No CEL. The recall erased the only data on the computer that backed up my claim. I had them run GDS report beforehand and it said average distance between regens was 213 miles. After the recall that number went to zero; after the next regen it is now 404, which correlates with the incorrect total number of regens and is not the actual average between. So GM can shove that in my face later. It is possible that the car needs to go through a few regen cycles before "deciding" to throw a CEL, so I'm trying to be patient. At least that won't take long, should have 2 or 3 more by the end of the week. My guess would be the recall software is just a CYA so they can say there is a CEL for frequent regens, but "frequent regens" means some extreme situation where it does one every 10 miles. I think they really just don't care if one person gets them every 100 miles and one gets them every 800 miles with the exact same driving conditions; not their problem if one person's car wears out prematurely after the warranty expires.
For what it's worth also in the data they pulled yesterday, I was at 92% soot per the differential pressure sensor, but "estimated soot per engine data" was 33%. Similar to the last discrepancy in September (97%/31%). And that's fine to them. That is how rough an estimate the DPF gives these cars to fire off regenerations. I guess mine was built on a Friday, as the joke goes, so too bad for me. 
So now just the waiting game again. I have an extremely important ~1,500-mile road trip in less than a month so I hope it does something before then.


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## MRO1791 (Sep 2, 2016)

"Now at 62% @ 69 miles" That is only a bit higher than what I typically see in my manual transmission car. It begins to go much slower right about at that point, my theory is that no passive regen can happen a the low soot levels (not enough soot fuel to burn, perhaps). Above 60% or so, it should slow down fast, I have also seen it get up to the 90s, then go down back to the 70s or 80s, then back up slowly. It really is bizarre. Are you able to monitor oil pressure? Also do you see any oil use, or rising levels? I ask because I wonder if that might somehow be a factor.


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## BodhiBenz1987 (Jan 13, 2018)

MRO1791 said:


> "Now at 62% @ 69 miles" That is only a bit higher than what I typically see in my manual transmission car. It begins to go much slower right about at that point, my theory is that no passive regen can happen a the low soot levels (not enough soot fuel to burn, perhaps). Above 60% or so, it should slow down fast, I have also seen it get up to the 90s, then go down back to the 70s or 80s, then back up slowly. It really is bizarre. Are you able to monitor oil pressure? Also do you see any oil use, or rising levels? I ask because I wonder if that might somehow be a factor.


I think that is correct, that around 50% soot mass, it reaches a level of packing where it can start to passively regen. I have seen others say theirs goes to 50 or so rather quickly, but then plateaus. Mine does not plateau or slow down. Well, it slows down to the point miles overtake soot % and after about 70 or 80% I'll start seeing it rise 1% each 2-3 miles instead of 1-3% each mile. There have been a few cycles, in the summer, when I saw it slow down more significantly at 80 or 90 percent, and those were the couple times I managed to get 300 miles between regens. Once it stayed at 98% for like 60 miles. My soot level basically never goes down. Occasionally it will drop 1% if I am stuck in traffic, of all things, and then regain the point when I am moving again. There was one time last spring where it dropped like 10%, from 70-60% on one drive. I have absolutely no idea why it did that that day, it was the same drive I've done 100 times. I get the feeling the measurement system is just not that precise, for one thing, so we probably all get some weird variations. But I think when you are getting normal cycles it's not as noticeable. The fact that I never see passive regeneration is one thing that leads me to believe I don't actually have that much soot in the DPF as the sensor is telling the ECM. I theorize it never reaches that point you mention where there is enough soot to passively regen. That would also explain why I'm not taking a fuel economy hit (other than during regens). I really thought I had a decent chance of the sensor and hoses fixing it, as that would be the main suspect for false readings. I can only figure now there is maybe a backpressure issue throwing off the reading, or an ECM problem. 
I think I can get a PID for oil pressure and have been meaning to try that one. Some of the trouble I run into with monitoring stuff is I have no idea what is normal. I have been watching the EGR valve position sensor but don't know what to make of it. That is another thing I still suspect, even though I don't have any EGR-type symptoms otherwise. Oil level seems to stay very constant. I am at 20% oil-life left and the level looks right were it was when I filled it. Oil is pretty black but that seems normal for these? ... I will send out a sample when I change it. I did last time and it came back with lower than average soot in the oil itself.


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## MRO1791 (Sep 2, 2016)

Very black oil is normal. Constant level, even a slight increase due to fuel dilution is also normal, and also why I don't go to ZERO on OLM to change oil. When you are able to get oil pressure readings, a trend I have noted in my 3 cars, the manual has the highest oil pressure, and the lowest average distance between regens... Not sure if there is any connection, but in that car I get pretty close to 100PSI when it's first started.. mid 90s for sure. The other 2 don't seem to get out of the 80's. Those numbers are crazy high, but normal for these engines apparently. They do have a variable oil pump. At cruising speed and low loads it drops down to the mid 20s, and then jumps up whenever the turbo spools up.


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## BodhiBenz1987 (Jan 13, 2018)

Second regen since the recall today, at 156 miles (about 120 or so of those were cruising on the highway). No CEL. Total average distance between regen dropped one mile, as you would expect, but the "distance between last six regens" went to 5,500 miles. I wish I knew what the parameter is that will supposedly set off a CEL for "frequent regens" so I know whether to keep hoping/wondering when or if it will set one off. The more I think about it the more I think it's likely just for doomsday scenarios like if the car is in active regeneration 50+% of the time or something.


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## BodhiBenz1987 (Jan 13, 2018)

Regen #3 since the recall Monday. Started at 156 miles, exactly the same as the last one. Followed a very similar pattern, climbing at a 1%/1 mile rate up until around 80, then slowed to 1%/2 miles. Went from 91 to 94 in about 20 miles, then from there shot up to 100 in about 5 miles. Again mostly highway, though I got stuck in a little local traffic today ... the slowest climb (91-94%) was actually the trafficiest chunk of the driving. Go figure. At the end of the regen (took a little over 7 minutes) it was down to 2%, but it instantaneously jumped to 11% after two miles. No CEL.


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## BodhiBenz1987 (Jan 13, 2018)

Found a third dealer to try and dropped it off yesterday. I really liked the service writer and they let me talk to a tech who seemed really attentive. I had pulled together a ton of history and information which I was hoping would help them. Friggin car decided it was a good time to throw the EGR Cooler code (no CEL when I dropped it off). So they have to replace that before they can diagnose anything else. Obviously not the cause considering the DTC would have come at some point in the last 12 months. So it's either another thing damaged by my regens, or more likely, just the typical issue that seems to affect a lot of people's cars. Have to wait until the part comes in, take it back, drive it a while and then can try to take it back to see if they can investigate the regen problem again. At least I really like this dealer so far; unfortunately they're out of my range to use their shuttle so it's a huge pain to get the car back and forth.


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## BodhiBenz1987 (Jan 13, 2018)

After waiting a month for the EGR cooler gasket to arrive, the EGR valve and cooler were replaced this week and I got the car back yesterday. Both the valve and cooler were described on the invoices as having "heavy build up". They also cleaned what the passageways after the cooler (I assume the tube from the cooler to intake). The good news is I really like the dealer, everyone I dealt with there was great, and the engine bay looks tidy after the job, everything buttoned up like it should be. Bad news is it really seems to have made no difference. I had my hopes up because right before I took the car back to the dealer it hung at 98% a long time (~50 miles), and when I got back home from the dealer it was at 95% (I didn't check it right when I picked it up). But on a drive today it did a regen about 10 miles into the drive and built back to 51% soot in 50 miles, same behavior as always. My fuel economy has been a small amount down in general recently but not profoundly and it's hard to really tell between the winter fuel and with things the way they are I'm not doing a regular commute. Just taking it out on the highway here and there for 60-70 miles. But since the repair the economy and power seem the same, soot % build-up is the same, the regen I had went the same, maybe took a little longer (10 mins vs 8). It does seem like it idles a little smoother, though I wouldn't have described it as bad before. My guess would be the EGR build up was a result of whatever is wrong, and is just going to build up again. Though it still never set off a CEL, and only that one DTC the dealer found. Given the EGR clogging I'm reconsidering that it IS actually building that much soot, rather than an incorrect reading like I have thought. Though I still don't understand how, seeing as large amounts of soot generally go hand in hand with reduced fuel economy or running issues or other things that trigger DTC/CELs. I thought maybe the clogged EGR was causing backpressure throwing off the pressure differential reading, but if that were the case it would be reflecting an accurate value by now with everything clean.
So at this point I have had the turbocharger, DPF, DPF differential pressure sensor and lines, EGR valve, and EGR cooler all replaced without any of it fixing the problem. I can't think of anything else other than an ECM problem, some subtle injector issue, or there's something about my driving.
I'll just keep driving it for now and see if anything improves over time with the new EGR components. I also bought some Stanadyne Performance Formula and will try that.


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## MP81 (Jul 20, 2015)

I haven't been following this too much, since I don't have much experience with this exact issue, but what I can say is: major compliments on not having one issue (or in your case, a lot more than one) and immediately declaring "this car is junk, Chevrolet is the worst, GM sucks" etc. 

Perhaps it was mentioned earlier, but what does the litany of sensors look like on the front portion of the exhaust on the Gen 2? The Gen 1 had a seemingly endless amount of sensors, and I expect they kept it similar on the 1.6.


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## BodhiBenz1987 (Jan 13, 2018)

MP81 said:


> I haven't been following this too much, since I don't have much experience with this exact issue, but what I can say is: major compliments on not having one issue (or in your case, a lot more than one) and immediately declaring "this car is junk, Chevrolet is the worst, GM sucks" etc.
> 
> Perhaps it was mentioned earlier, but what does the litany of sensors look like on the front portion of the exhaust on the Gen 2? The Gen 1 had a seemingly endless amount of sensors, and I expect they kept it similar on the 1.6.


If I'm honest I think I have emitted a few "GM sucks" but specifically in moments of frustration regarding parts supply and their insistence on "no CEL, no problem" ... but that second one is pretty universal to all new cars, and probably the first one to some degree too. I think the car is amazing and I continue to be impressed with Chevy/GM design, both mechanically and cosmetically ... honestly even the emissions system is impressive, I just wish it worked like it should. I think I mentioned it in another thread, but compared to my 1978 diesel sedan, this car gets twice the fuel economy, is twice as fast, and without smelling or leaving a single soot mark on my driveway (the cost of all that of course is the complexity). Really the fact that the car is so great is why I just keep going nuts over this ... if I didn't love it so much I'd have ditched it long ago. I also don't think what's going on is a design flaw, but some sort of fluke ... maybe it just happened, or maybe it was human error, but I don't think it reflects poorly on the 1.6L powertrain or the Cruze model. 
Another thing worth noting is that despite all this drama, the car has been reliable. Never once has it had a problem that disabled it, not once has it gone into "countdown" for emissions stuff, not once has it failed to complete a regen and has never even given me the "keep driving". Even when the turbo failed, it did so in a way that not only was it drivable when the light came on, I didn't even notice a power issue. Even with the clogged EGR it drove pretty much normal. I just know the wear and tear will eventually catch up to it, and the regens are a nuisance. 
I think the sensor setup is fairly similar to the Gen 1. There is an NOx sensor on top of the DOC, two EGT sensors in the DPF, an EGT sensor in the pipe after the DPF, a soot sensor after the DPF, and then the second NOx sensor after the NOx catalyst farther back. And the pipes for the DPF differential pressure setup feeding into the top and bottom of the DPF. If nothing else I've learned a lot about modern emissions setups over the last year.


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## BodhiBenz1987 (Jan 13, 2018)

So just a little update on the white-whale regen problem. The first full cycle between regens after the EGR/cooler replacement lasted about 180 miles, same as always. But then it actually went just over 600 miles before the next regeneration, which happened today. It built a little slower than it had been, and was at 100 miles before it hit 50% ... it actually went up and down a little while in the 80s%, then climbed really slowly from there (it went over 400 miles since hitting 80%). After the regen today it went right up to 61% in 39 miles ... on the same drive I've been doing over and over. I'm hoping it will stabilize again but it looks like it's headed for another one in the 100-200 mile range. Puzzling beyond words. I've been driving basically the same highway loop of 60-80 miles for the last 1,000 miles, so I just can't understand what the difference between today and the other days is. It just seems like every time it completes a regen, it's a crapshoot whether it's going to decide to re-build soot from 0-100 in 70 miles or 600. Really hoping the buildup slows down on this next one because the last one had my hopes up ... 600 is actually in the realm of normal (once per tank).


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## BodhiBenz1987 (Jan 13, 2018)

Well after 600 miles between the last two regens, it just did one after 130 ... it was at 96% before it hit 100 miles. Same driving, like 95% highway. It honestly blows my mind how little sense it makes and I've run out of theories. With the same driving, one time it gets 600 miles, the next 100. Meanwhile my fuel economy had been a bit down, and after today's regen it has really tanked. It completed the regen as normal but for the next 50 or so miles on flat highway it was struggling to get 50 mpg ... with a stretch of tailwind downhill I barely managed 60. So it looks like it will be going back to the dealer next week or whenever they can take it ... I can live with the regen stuff but not 10-15 mpg worse fuel economy. Even with all the stuff going on over the last year, the fuel economy has never been near this low on the highway even in dead of winter. It actually stayed excellent even with the regens, which is one reason I stuck with it all this time. It breaks my heart thinking how insanely good this car was at one point ... two years ago I took it on a 1,200-mile out-and-back road trip and got 66 mpg for the whole trip. I can always try to find another one since I occasionally see a used manual pop up for sale, but I hate to let go of one that is the first (and probably only) car I ever ordered new ... especially never knowing what went wrong. Hopefully the fuel thing will improve ... I could keep living with the rest.


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## Snipesy (Dec 7, 2015)

Dude. 50 mpg is already above average. Relax.


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## BodhiBenz1987 (Jan 13, 2018)

Snipesy said:


> Dude. 50 mpg is already above average. Relax.


Well, fair advice that I should relax ... even if it is lower, it is just a car. I am an overthinker which has admittedly gotten worse since I have nothing to do but drive in loops staring at my fuel economy. My concern is more about the relative drop on familiar stretches than it is about the specific numbers. If my car always got 50 mpg on the highway I wouldn't complain ... that's 20 mpg better than anything else I have owned. But seeing a drop is bothersome, whether it's from 60 to 50, or 35 to 30. If that makes sense. That said I guess it would be best to just see what my next couple tank averages are, and not make assumptions based on the DIC economy tracker which I know is not always perfect.


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## Cruz15 (Mar 17, 2016)

BodhiBenz1987 said:


> Well after 600 miles between the last two regens, it just did one after 130 ... it was at 96% before it hit 100 miles. Same driving, like 95% highway. It honestly blows my mind how little sense it makes and I've run out of theories. With the same driving, one time it gets 600 miles, the next 100. Meanwhile my fuel economy had been a bit down, and after today's regen it has really tanked. It completed the regen as normal but for the next 50 or so miles on flat highway it was struggling to get 50 mpg ... with a stretch of tailwind downhill I barely managed 60. So it looks like it will be going back to the dealer next week or whenever they can take it ... I can live with the regen stuff but not 10-15 mpg worse fuel economy. Even with all the stuff going on over the last year, the fuel economy has never been near this low on the highway even in dead of winter. It actually stayed excellent even with the regens, which is one reason I stuck with it all this time. It breaks my heart thinking how insanely good this car was at one point ... two years ago I took it on a 1,200-mile out-and-back road trip and got 66 mpg for the whole trip. I can always try to find another one since I occasionally see a used manual pop up for sale, but I hate to let go of one that is the first (and probably only) car I ever ordered new ... especially never knowing what went wrong. Hopefully the fuel thing will improve ... I could keep living with the rest.


Did you do any other maintenance during this time? Did you get new tires? An alignment?


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## BodhiBenz1987 (Jan 13, 2018)

Cruz15 said:


> Did you do any other maintenance during this time? Did you get new tires? An alignment?


Nothing that recent, I had the tires rotated in March and EGR cooler/valve in early April ... definitely thought it could be the latter but it seemed at least close to normal after that (been about 1,000 miles). I drove it today and it seemed a little more typical though it was a shortish drive. I'm going to try to be patient and observe for a while. It just seemed like it didn't "recover" after the regen, even though it said it was done and the temps came down and all ... whereas usually once it's done it bounces right back to normal driving. It's possible the wind was worse than I thought the other day, though it didn't seem enough to be that dramatic. With some nice weather coming up I will try a few drives and see where it goes.


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## oregon_rider (Jul 21, 2017)

Hello BodhiBenz...

Sent you a private message with more detail...

I came across the following delphi website relative to exhaust gas temp sensors :









Making sense of your sensors: Exhaust gas temperature sensor | Delphi Auto Parts


Thanks to ever-stringent emissions legislation, exhaust gas temperature sensors are becoming increasingly popu




www.delphiautoparts.com





*"Unnecessary DPF regeneration: faulty sensors can also lead to unnecessary regenerations, causing inconvenience to the vehicle owner."*

Best Regards,
Jeff


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> Hello BodhiBenz...
> 
> Sent you a private message with more detail...
> 
> ...


Thanks for the idea and encouragement, Jeff. It seems like a theory worth looking into. As mentioned in our private message chain, the need to "relearn" the sensors following replacement I think puts it out of my DIY realm. The last few times I've driven the car there seems to be significantly more wrong now than the regens ... maybe the same cause as the regens, or maybe a result of the regens. My fuel economy has trickled down over the last month, and I'm now getting 10+ mpg worse on the highway, even with summer fuel and Stanadyne. It also just feels like I have to lean into the throttle a lot more to maintain 60 mph on the highway, plus I find myself having to downshift where I never did before. It's not a total dog but it has to try harder than it used to. With no CELs there is just an endless list of what could be wrong at this point. So, I am going to call the dealer tomorrow and see if they can give it another shot. I am going to ask them to look at the EGT sensors ... maybe they could test and clean them, even if I pay for the labor. 

If they don't find anything I'm not sure what to do next. I don't want to give up on the car because it's special to me, but the reality is I really don't _need_ it anymore. I work from home and the museum I volunteered at is closed for the foreseeable future, and I have no need to travel other than the pleasure of the drive itself. And it is not pleasurable to drive anymore ... it was one thing when it was just the regens and the car was awesome in between. I just think if I sell it I will really regret it, and wonder if there was something else I could have done. I guess I should go one step at a time and see if anything can be done to restore the economy and performance ... could be something unrelated like a stuck caliper or a gummed fuel filter. If I get that back I think it will be worth continuing to plug away at the regen puzzle.


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## BodhiBenz1987 (Jan 13, 2018)

Just an update: The car has been at the dealer for a few days and they're still looking. As expected they couldn't find any stored codes or anything obvious but they agreed the regen total is excessive at this mileage. They want to look into the injectors to see if there's one that's maybe leaking on the exhaust stroke in between regens or something along those lines. I'm impressed at the effort they are putting in and just hope GM Tech doesn't do what they have done in the past and tell them not to do anything. I think the thing that has really been the downfall of my whole pursuit of this is whatever glitch happened with my total regen count. It's impossible to explain and seems implausible ... it's taken over 15k miles for the data to start looking excessive to the point I have even a slight leg to stand on. Even now, the data says I'm averaging 375 miles which doesn't sound as bad as the reality (around 220 miles). Anyhow, hopefully it should be enough to finally convince GM Tech ... if the numbers _are_ right, I had 13 regenerations in my first 14k miles, and 60 in the last 14k miles. I'm not sure whether I hope they find something with the injectors or not ... on the one hand, it would be great to have the puzzle solved, but on the other, a bad injector for almost 20k miles I would think would have a detrimental effect on the internals of the cylinder so I doubt the car would ever go back to what it was when new ... worried that might be why my fuel economy finally stared to tank. I still think it is possible it's an issue with how the ECM calibrates soot, too, but I think that would be impossible to diagnose. Anyhow, at least from what I can tell the car is in good hands now, which is a positive, so we'll see. I miss it. I like driving my old cars but the Cruze was king for highway cruises.


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## BodhiBenz1987 (Jan 13, 2018)

After three weeks at the dealer, GM Tech told them nothing is wrong with it ... based on static data, not driving. I'll give credit to the dealer for at least genuinely trying and being persistent with it, much more than anyone else. They found a small leak at the crank case vent tube in the inlet tube (pre-turbo) which they said didn't seem to be affecting anything but had to be fixed before diagnostics could proceed. I guess they reset a couple things, they didn't say what. So it's possible one of those things could somehow help. They did a service regen and confirmed the car does regens successfully, which I already knew having watched it do 60 #$^%ing regens over the past year. GM said the only way the regens are too frequent is if it is literally doing them back to back. So it can regen every 50 miles and or every 1,000 miles, who cares, not GM's problem! Picking it up tomorrow and that's that. They basically politely said only bring it back if I have a CEL. At least I have somewhere I feel I can trust when it reaches that point.

So I basically have no recourse left. This dealer was great and that didn't make a difference, so there's no point looking for another dealer. It's all the same GM BS. I'm hoping maybe the air inlet leak was somehow what was causing my mpg drop in which case it could go back to getting great economy in between the regens. If not I'll have to rethink things. I'm kind of to the point where I don't need the car so it's just a matter of sentimentality. Like I've said before, it's such a cool little unicorn that I'd hate to see it go. But I'd also hate to drive it knowing it's potentially damaging itself, or leave it sitting and rot away from disuse. Oh well. The unerring certainty of machinery, right?


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## phil1734 (Aug 30, 2019)

I apologise for not re-reading this entire thread, but during steady state highway cruising is your milage still where it should be?

I'm starting to get mildly paranoid my car may be doing the same thing. I initially chalked it up to only doing short trips while working from home, but I've now put on over 1,000 miles of my previous regular commute and my 450 mile average continues to drop. It used to hang out around 53 or 54, and it's now 45.5.

I did during that time change to my summer wheels and tires, which are significantly heavier, a touch wider and much stickier, so I was expecting a drop, but not 20%. And it should have dropped to a new normal and stayed there, not continued to lose 1mpg every week like it has for the last month.

The only pattern I've started to notice is that my steady state cruising mpg is normal - about 55-60. But if I give it any throttle at all, it immediately drops down to the 20s.

It's certainly something I'm going to keep watching. Might even pull the other wheels out of storage if it continues, just to see if I'm going insane.


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## BodhiBenz1987 (Jan 13, 2018)

phil1734 said:


> I apologise for not re-reading this entire thread, but during steady state highway cruising is your milage still where it should be?
> 
> I'm starting to get mildly paranoid my car may be doing the same thing. I initially chalked it up to only doing short trips while working from home, but I've now put on over 1,000 miles of my previous regular commute and my 450 mile average continues to drop. It used to hang out around 53 or 54, and it's now 45.5.
> 
> ...


At this point even I wouldn't want to re-read the entire thread, haha. To answer your question: During most of the year and a half that this has gone on, my highway mileage continued to be spectacular overall. Obviously it dropped during the actual regen process but would always bounce back up. The last longish trip I did was in October, just 200 miles to DC and back but for that full distance it did 65 mpg ... including with a regen and a bit of city driving in the middle. My last 450 has usually been around 54. The trip odometer I left running since last fall was at 53 for about 7k miles. 
However, over the last couple months, I have seen pretty much exactly what you describe develop. I used to be able to cruise steadily on the highway and basically keep that instantaneous mpg between 50 and 70, unless I had to pass someone. Even then it would usually reverse-spike down to the 40. Now I see it dip really low even for just a light touch of the pedal to maintain speed. I usually go by the economy tracker screen with the bar graph on it, and that has been the biggest indicator that something is off for me. If you have that screen I find that most helpful. Instantaneous is a little harder to really judge because it is pretty sensitive. The economy tracker gives you bars of three miles, and for my regular "commute" was very consistent what height bars I would see on what stretches. Those have gone down about 10 mpg for me. 
Again thought the mpg drop was just over the last couple months, whereas the other 12+ months with the frequent regen problem I was still seeing awesome economy. So I don't know if they are related or how. My guess would be whatever is causing my regen issue is starting to catch up with the engine and/or its management systems. Could be unrelated though. I just got the car back yesterday and drove it 20 miles home, so hard to judge, but I was still seeing the lower fuel economy and that behavior of huge down spikes in instantaneous economy with a little feather of the pedal. Unfortunately with no CEL/DTCs it doesn't matter if I get a regen every 50 miles and get 20 mpg on the highway ... GM will say nothing is wrong.
In your case, I wouldn't expect that dramatic a drop from the different wheels ... but wheels/tires do play a pretty big factor in mpg (especially when you are talking about economy as high as these can get) so I suppose it's possible. Maybe it's worth a try to swap them out just to rule it out. I know these cars are always "learning" as they go, so it's possible it keeps adjusting parameters to the new wheels. I find it a little odd that they would make the acceleration moments drop, and not the rolling ones, but it might be that the increased rolling resistance is just requiring more dramatic acceleration to gain back lost momentum. Do you have anything to track regens and other data? That could also be helpful. A ScanGaugeII or an OBDLink with Gretio or BiScan could give you an idea if regens are part of what is dragging your mileage down. They definitely absolutely tank mileage during the process, so a lot of them, or very long ones, could put in a big dent. One thing I had going for me is that mine were always pretty short ... took maybe 8 miles ... so my overall mpg could catch up between.


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## phil1734 (Aug 30, 2019)

I have a Bluetooth obd adapter but haven't pulled the trigger on a supporting app yet. Once I do that and can monitor regens I'll go from there. I haven't noticed an overabundance of them, but they could be slipping by.

The other thing is I've been trapped in a heatwave for close to a month now as well. My AC hasn't been off at all, which is pretty unheard of for Michigan mornings. I've heard the first gens would experience a more-significant-than-expected mpg hit with copious AC use.


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## BodhiBenz1987 (Jan 13, 2018)

phil1734 said:


> I have a Bluetooth obd adapter but haven't pulled the trigger on a supporting app yet. Once I do that and can monitor regens I'll go from there. I haven't noticed an overabundance of them, but they could be slipping by.
> 
> The other thing is I've been trapped in a heatwave for close to a month now as well. My AC hasn't been off at all, which is pretty unheard of for Michigan mornings. I've heard the first gens would experience a more-significant-than-expected mpg hit with copious AC use.


It could be a combination of the A/C and the wheels/tires. I'd have to do some searcing, but now that I think about it I think there was another thread where someone changed wheels and tired and saw a big drop ... I don't recall if that turned out to be the cause. I don't tend to notice a huge dip due to A/C, but I also pretty rarely crank it, at least after the initial phase of cooling down the oven-like cabin when I first get in the car (wish I could fit it in my garage). I did tend to get my best mpg on early morning commutes when I didn't even need the A/C, or late-night drives when it cooled down enough to go without it. If you already have the Bluetooth reader, the apps are pretty inexpensive and handy to have as diagnostics, even if you don't use them all the time. In addition to the regen-related info you can check injector balance, boost, etc and see if anything looks out of whack.

I took mine for an 80-mile drive today on what would have been my commute had the camps I work at not been shut down. It seems to be a little more itself than it had been lately, at least based on the information on the economy screen. I will have to give it some time to see how it averages out over the next week or so. My "last 450" took a big hit from having a service regen done, plus a lot of idling was needed for diagnostics, so it'll take a while to give me an accurate picture.


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## phil1734 (Aug 30, 2019)

It's finally cooled off enough here that I didn't need the AC on the drive into work this morning. Mileage was normal after finishing up an interrupted regen from last thursday. By normal I mean ~55-65 cruising, 40-50 uphill or passing. Including the regen the mileage for my 30 mile commute finished at 46.7mpg. I know I've seen higher since the wheel swap so I'm chalking this first data point up to the regen cycle and hopefully nothing else.

I've started a spreadsheet for myself to track with for the next month and we'll see what happens. If my commute mileage stays in the low 50's I'll chalk it up to the wheels and tires. I know these things are heavy so perhaps not only am I taking a hit from AC and the additional rotating mass, but I'm actually using enough additional fuel during city driving that I've substantially diminished my regen interval, creating a trifecta of a worse-case scenario.


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## BodhiBenz1987 (Jan 13, 2018)

phil1734 said:


> It's finally cooled off enough here that I didn't need the AC on the drive into work this morning. Mileage was normal after finishing up an interrupted regen from last thursday. By normal I mean ~55-65 cruising, 40-50 uphill or passing. Including the regen the mileage for my 30 mile commute finished at 46.7mpg. I know I've seen higher since the wheel swap so I'm chalking this first data point up to the regen cycle and hopefully nothing else.
> 
> I've started a spreadsheet for myself to track with for the next month and we'll see what happens. If my commute mileage stays in the low 50's I'll chalk it up to the wheels and tires. I know these things are heavy so perhaps not only am I taking a hit from AC and the additional rotating mass, but I'm actually using enough additional fuel during city driving that I've substantially diminished my regen interval, creating a trifecta of a worse-case scenario.


A regen will be a pretty solid hit to the economy over a shorter window. My commute is 41 miles one way and I would usually see the trip economy at 60 mpg or over for that drive in the morning, even mid-60s if it was summer and no traffic issues. If I had a regen during that drive it would drop that to 54-56 mpg. Mind you that's all based on the DIC/Smart Driver information which isn't entirely accurate/consistent. But still a good reflection of the effect. I don't know how much effect it has overall for me. My case is so strange though, I'm not sure how it compares to a normal car. 

It's possible the extra effort needed in the city could increase soot buildup but I would think your regens are still spaced enough for it not to make a huge difference over the 450-mile interval. But like you said it could just all be adding up.


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## oregon_rider (Jul 21, 2017)

On the topic of the AC - there are two modes for AC - one with green light for "eco mode"... To compare your mpg readings - do you folks run eco after you get things cooled down? (less load on car in this mode...)

jeff


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## phil1734 (Aug 30, 2019)

No eco mode on either of ours (since I know they're both manuals) because they don't have the auto start/stop.


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> On the topic of the AC - there are two modes for AC - one with green light for "eco mode"... To compare your mpg readings - do you folks run eco after you get things cooled down? (less load on car in this mode...)
> 
> jeff


As phil said we don't seem to have the eco mode on ours. I do switch mine to recirculate once the car is cooler the ambient temp. I find with recirculate once the air gets nice and cool I can turn it down pretty low and maintain comfort.


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## phil1734 (Aug 30, 2019)

Well I'm 250 miles into tracking fuel mileage. No regens yet, so I don't think I'm experiencing your issue after all.

What I do think is happening is that it is in fact the AC killing my mileage - in particular it's the "Enhanced Front Defogger" which is a feature I can't find mentioned anywhere other than the DIC, and as far as I can tell is just a fancy way of saying "We turned the AC on to de-humidify the car without telling you."

So in other words, my car has been using the AC even when I thought it wasn't, and according to my number from the past week, AC costs me a pretty steady and predictable 4mpg (~8%, perfectly reasonable,) on the highway. This pretty much explains my confusion as to why some days I was seeing 52-54 mpg on my commute, and others were 46-48, seemingly out of no-where.


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## BodhiBenz1987 (Jan 13, 2018)

phil1734 said:


> Well I'm 250 miles into tracking fuel mileage. No regens yet, so I don't think I'm experiencing your issue after all.
> 
> What I do think is happening is that it is in fact the AC killing my mileage - in particular it's the "Enhanced Front Defogger" which is a feature I can't find mentioned anywhere other than the DIC, and as far as I can tell is just a fancy way of saying "We turned the AC on to de-humidify the car without telling you."
> 
> So in other words, my car has been using the AC even when I thought it wasn't, and according to my number from the past week, AC costs me a pretty steady and predictable 4mpg (~8%, perfectly reasonable,) on the highway. This pretty much explains my confusion as to why some days I was seeing 52-54 mpg on my commute, and others were 46-48, seemingly out of no-where.


That sounds believable especially if you've not really had to use A/C in the past. Our summers are pretty nasty where I am so my summer baseline includes A/C ... though like I said in a post before I think, I should factor in that the last two summers I was usually doing one way of my commute in early morning. I should see if it's listing the enhanced defogger for me .... I've seen it before but rarely expand that menu. I actually had my first commute today for the first time since March ... but drove up mid-day instead of morning and it was brutal. I usually do ~62 mpg for that leg of the commute and today it was 58 with perfect traffic other than a little hassle at the end. It could have been from running the A/C higher than normal ... plus the A/C just having to work harder every minute. Or I might still have something else going on ... my fuel economy definitely seems to have improved some after the last dealer visit, but it's still a bit down. It doesn't seem to really be worse in local driving so my overall average isn't down that much. I guess it's not the end of the world if it stays there ... other than the OCD part of me that looked forward to trying to top my own numbers next time I get out on a real road trip ... or even a cross country trip. I wanted to do a Cannonball Run but for mpg ... it was probably just a pipe dream anyway but a fun thought for these cars.


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## phil1734 (Aug 30, 2019)

Might be a long shot, but perhaps this is part of your issue? Extra engine load=extra fuel=extra regen maybe?









What a dang mess!!! Front & Rear pad & rotor...


So, I have an update. After driving for a full tank, I've noticed my average gas mileage has risen by about 20% if not more. Ever since I bought my car (less than a year old and Chevy Certified) I was always a bit disappointed by my gas mileage. I would average maybe 23-26MPG when doing the math...




www.cruzetalk.com


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## BodhiBenz1987 (Jan 13, 2018)

phil1734 said:


> Might be a long shot, but perhaps this is part of your issue? Extra engine load=extra fuel=extra regen maybe?
> 
> 
> 
> ...


Thanks for the thought, it had crossed my mind especially in early summer when I was starting to see diminished fuel economy, that something could be sticking. I haven't updated this thread in a while, but my economy did come back up ... could have been a couple things: I did have a small leak in the intake where the CCV enters the hose and the dealer fixed it, which may have helped, or it could have just been that summer fuel finally reappeared. My last five tanks were all over 57 mpg, and one I was really close to 60 ... a lot of highway time obviously but those are actually the highest non-road-trip numbers for full tanks I've seen. So I think sticking brakes are unlikely at this point, though probably good idea for me to check them myself at some point since the car sits more than it used to. Despite the economy improvements I do continue to have the frequent regens, though more erratically spaced out. I'll post a longer update at some point but the patterns between regen intervals continue to make me lean toward it being something electrical/learning-related.


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## boucivicsir (Aug 17, 2021)

i know it's been 9 months or so... is there a conclusion? maybe some updated info would help some others in need (not me .. at least yet)

i'm still getting used to my '17 cruze TD 9 speed. i'm at 48 mpg which i think is great for doing 70mph with a/c and luggages / passengers etc.


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## BodhiBenz1987 (Jan 13, 2018)

boucivicsir said:


> i know it's been 9 months or so... is there a conclusion? maybe some updated info would help some others in need (not me .. at least yet)
> 
> i'm still getting used to my '17 cruze TD 9 speed. i'm at 48 mpg which i think is great for doing 70mph with a/c and luggages / passengers etc.


Unfortunately not really, although the regen behavior has at least improved dramatically since I originally made the post back in 2018. Despite me finding a dealer who really made an effort to look into the issue, GM Tech would not allow them to look into it anymore unless a CEL comes up, so there was really nothing I could do and I'm just trying to take care of the car and enjoy it at this point. One thing that did happen that seemed to make some difference is that I noticed a rip in the sheathing on one of the EGT sensor wires (EGT 3). I had the dealer look at that and they said the wires inside it were not damaged and re-wrapped the outside sheathing. They put the sensor back on and did a reset. That was in November. When they did that I had 95% soot, and it stayed there for like 400 miles after they did it. Then I had a regen cycle of 712 miles, which is great, followed by one of 828, which actually only initiated because of distance not soot (first time I have had that happen). But then it started to vary wildly again and my last handful of regens miles-between have been: 177, 645, 144, 325, 316, 740. Basically all the same driving, with the exception of that last one I actually did a fair bit more stop and go than normal (still a good % of highway) so in theory that is sort of backwards. When it has the longer intervals between regens, it goes to 88% and stays there or goes up and down a percent or two. When it does the more frequent regens the soot climbs fast and doesn't slow down, or slightly slows down while still climbing fairly fast. I do also use a fuel additive that is supposed to help foster passive regens, but have only been using it for two tanks so the verdict awaits on that. 
I am almost certain at this point that my car's erratic behavior in terms of regens is due to a calibration problem, leading it to "think" it has more soot than it does, and the amount it is off varies. I am considering at some point just changing that third EGT sensor on principle, since for one reason or another, fiddling with it seemed to change something. As far as I can figure, the EGT temperatures and some other parameters are incorporated into how the car reads soot level, in addition to the raw reading it pulls from the pressure differential sensor. I have not been able to find a definitive explanation of this or confirmation of it, and I am somewhat worried trying to change it myself could make the situation worse, especially since I don't have the tech to do a reset once it's installed. The fact that the car is at least hitting some normal-to-strong intervals makes me even more hesitant to try changing stuff based on my own guesswork. 
Another piece of evidence that something is a bit wacky in my car is that it absolutely did walk back its own "lifetime total regen" number. When I first said that in 2018, the dealer and everyone else thought I was nuts because that number should not be variable or change ... it should be untamperable or whatever the term is. It did another little flip last year, and I have it documented. It had 73 regens when it went to the dealer in July 2020, and 55 when I had them read it in November. GM had been using that number, and the resultant miles-between-regen avg, to argue the car was normal. As I had tried to tell them, that number is not correct, and now the average isn't either. It does not really matter, as this did not change GM's stance, but I think it is interesting to know. 
So bottom line, the car is still quirky, and there has been no conclusive discovery of why. But it has vastly improved from when I started this thread, when it was doing a regen literally every 100-200 miles, sometimes less. Given that it took a turn for the better after the EGT sensor was removed and tidied up, I think that is involved, or maybe just the act of resetting the computer altogether. It also had small improvements two previous times the dealer did some kind of reset for other repairs (the intake seal and the EGR cooler), but sort of "learned down" shortly after, alternately getting lower each cycle. 
So still kind of a puzzle. Otherwise the car is doing great, knock on wood. I do not drive it as much anymore due to personal circumstances; I have only put about 4,000 miles on it this year so far. But it still gets great economy and has done a nice job getting me too and from my eye doctor appointments. My lifetime average is still around 51 mpg for 36k miles. Still pops up to the 60s when I get it out on the open road for a stretch here and there.


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## boucivicsir (Aug 17, 2021)

too bad for the not so happy conclusion. i know it's almost impossible but i would try to swap the 'ECU' (maybe different name, i'm coming from the honda world) i'm wondering if it's a glitch in the calibration, but in the end when they make updates, they likely write over and then there are some checksum to be sure there's no errors. my guess would be a sensor that makes a hiccup once in a while and the calib is so 'pointy' that it triggers a regen, but not a cel. (sorry i'm french spoken so some sentence structure might be complex)
good luck!


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## oregon_rider (Jul 21, 2017)

Hi Cecily.

When I ran the xenum dpf additive (xenum nex10) you just started using - my soot load was down at less then 25 percent until I loaned the car to my lead footed brother when he was in town. Then it popped up to 40-50 percent. I was running it at a double dose at the time. Side benefit is that it will also keep your egr clean.









NEX10™


Significantly improves performance of the engine Nex10™ is a special diesel additive, making the fuel burning process more efficient and clean. It significantly improves the engine’s performance for less




xenum.com





Have you had a chance to try the def additive that I sent you yet? Or are you waiting for a def refill?









ADMAX - Xenum Power of Technology


Professional product developed to ensure the reliability of the AdBlue® system. Increases the efficiency of AdBlue®. Prevents the formation of crystals in




xenum.com





Jeff


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## BodhiBenz1987 (Jan 13, 2018)

oregon_rider said:


> Hi Cecily.
> 
> When I ran the xenum dpf additive (xenum nex10) you just started using - my soot load was down at less then 25 percent until I loaned the car to my lead footed brother when he was in town. Then it popped up to 40-50 percent. I was running it at a double dose at the time. Side benefit is that it will also keep your egr clean.
> 
> ...


Hi Jeff, I have not had a chance to try the DEF additive yet. Well, I did have a chance but amid a few hectic weeks I forgot to add it when I refilled the DEF. I might wait until it gets down to half a tank of DEF, add it, then top off to make sure it's mixed. I have done two fuel tanks with the DPF additive and I think it's helping a little, though I am still getting soot up to about 85% before I see it plateau. But it stayed at 88% for so long I made it over 700 miles before my last regen. I think my soot% parameter is just incorrect for whatever glitchy reason. However if I can continue to have it plateau at 85%, it is still a big improvement as that gets me longer intervals on average. I will refuel in the next week and will try a bit higher dose. Last time I put in a somewhat small dose since the station was busy and a guy in a pickup truck was hovering annoyed behind me while I filled up (probably thought I was blocking a diesel pump with a gas car haha) ... so I just put in a quick small dose.


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## oregon_rider (Jul 21, 2017)

BodhiBenz1987 said:


> Hi Jeff, I have not had a chance to try the DEF additive yet. Well, I did have a chance but amid a few hectic weeks I forgot to add it when I refilled the DEF. I might wait until it gets down to half a tank of DEF, add it, then top off to make sure it's mixed. I have done two fuel tanks with the DPF additive and I think it's helping a little, though I am still getting soot up to about 85% before I see it plateau. But it stayed at 88% for so long I made it over 700 miles before my last regen. I think my soot% parameter is just incorrect for whatever glitchy reason. However if I can continue to have it plateau at 85%, it is still a big improvement as that gets me longer intervals on average. I will refuel in the next week and will try a bit higher dose. Last time I put in a somewhat small dose since the station was busy and a guy in a pickup truck was hovering annoyed behind me while I filled up (probably thought I was blocking a diesel pump with a gas car haha) ... so I just put in a quick small dose.


 I thought I had the "secret sauce" when I was able to run renewable diesel that has a cetane of about 80.. No soot buildup in egr or dpf. Then the local independent oil company I got a cardlock account with quit stocking it at their pump in NW Portland. So then I switched to running the DPF additive (xenum nex10).

I had issues with a blocked scr cat - which was replaced under warranty - so running the def additive (xenum admax) prevented crystallization buildup in the scr cat on short trips where it can't get up to temp etc. Also prevents issues with the DEF injector.

Just when I think I got it all figured out where i didn't have to worry any longer - I punched in my car at carmax website and got a crazy offer and sold it to them. Took about an hour and a half - and that was because they initially mis-spelled my name on the paperwork and had to re-do it. Pretty efficient process. 

I still have a dozen bottles of each additive in case anybody wants some (I had it shipped in from europe and it isn't readily available here). Just thought I'd mention it here before I throw them on to e-bay. And I still need to send a few bottles out to a couple of folks here - sorry for the delay - busy with work.

thanks,
jeff


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## Carminooch (Mar 23, 2018)

oregon_rider said:


> I thought I had the "secret sauce" when I was able to run renewable diesel that has a cetane of about 80.. No soot buildup in egr or dpf. Then the local independent oil company I got a cardlock account with quit stocking it at their pump in NW Portland. So then I switched to running the DPF additive (xenum nex10).
> 
> I had issues with a blocked scr cat - which was replaced under warranty - so running the def additive (xenum admax) prevented crystallization buildup in the scr cat on short trips where it can't get up to temp etc. Also prevents issues with the DEF injector.
> 
> ...


I don’t want to deviate from the original conversation but I was going to go the carmax route and literally THE next day, a hurricane pushed a tree over on top of my Cruze and it looks like it was out in a hail storm. I had such a rock solid offer that I was about to make the jump the second I found a TDI I liked. Now, 27 days and not a peep from insurance yet, still waiting. I’m hoping it’s totaled, otherwise I’m taking a huge hit in selling price from it having previous damage. Sorry to go off on a tangent, it’s been a frustrating month


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## oregon_rider (Jul 21, 2017)

Carminooch said:


> I don’t want to deviate from the original conversation but I was going to go the carmax route and literally THE next day, a hurricane pushed a tree over on top of my Cruze and it looks like it was out in a hail storm. I had such a rock solid offer that I was about to make the jump the second I found a TDI I liked. Now, 27 days and not a peep from insurance yet, still waiting. I’m hoping it’s totaled, otherwise I’m taking a huge hit in selling price from it having previous damage. Sorry to go off on a tangent, it’s been a frustrating month


 Condolences on the car problems. Fingers crossed that it gets totaled out for you.

jeff


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