# Diesel 2nd gen, hesitates when cold



## Carminooch (Mar 23, 2018)

As the title states, the car tends to hesitate when trying to drive for the first mile and then it clears up. It happens only under medium to low throttle. I’ve mentioned it to the dealer and despite it happening every time I drive the car, it magically “fixes” itself at the dealer.

No check engine light, dealer of course never finds anything wrong with the car. Does anyone have any advice? What can I do?


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## MP81 (Jul 20, 2015)

How many miles?


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## MRO1791 (Sep 2, 2016)

Carminooch said:


> As the title states, the car tends to hesitate when trying to drive for the first mile and then it clears up. It happens only under medium to low throttle. I’ve mentioned it to the dealer and despite it happening every time I drive the car, it magically “fixes” itself at the dealer.
> 
> No check engine light, dealer of course never finds anything wrong with the car. Does anyone have any advice? What can I do?
> 
> ...


How bad is it? What temperature are you talking? When you say hesitate, is the engine doing a misfire? Is it just lacking power and throttle response? I think it could be normal for an cold engine to be sluggish until it warms up. Actually, it's a good idea to be light on the throttle on any cold engine to give it warm up time. You might be surprised to know this engine will push oil pressure to close to 100PSI when cold! It could also be programmed to limit engine power to protect the engine (and turbo) before it's warmed up.


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## Carminooch (Mar 23, 2018)

I’m at 36,000 miles. Im talking temperatures 60f or lower. Sometimes close to 70f. I typically like to try to let the car idle for 2-3 minutes to get the fluids moving and even then, it hesitates for the first minute. The car doesn’t quite misfire, feels like a clogged fuel filter but it isn’t. Press the accelerator, car stumbles a bit (doesn’t misfire or sound “off”) but and finds itself. 

It’s too sporadic and intermittent to be a built in feature so I’m stumped. The dealer of course never sees this happen.


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## MRO1791 (Sep 2, 2016)

Ok automatic or manual? That does sound normal, I have 3 of these, none do as you describe. (I have manual and 2 autos).

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## MRO1791 (Sep 2, 2016)

You could also be dealing with an electrical issue with the accelerator pedal itself. It's just a variable resistor that provides input to the computer on these cars (actually now most all cars).


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## MP81 (Jul 20, 2015)

Any issue starting on those occasions?


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## Carminooch (Mar 23, 2018)

No issues starting. The car is a manual. I have my own far fetched theory... 

There’s splattered soot on my turbo near the wastegate. It’s been like that since 1000 miles in. I’ve raised the issue with the dealer and they told me again, that it’s normal.

I find it hard to believe that any exhaust escaping before the emissions system is normal. Call me crazy but diesel exhaust can either smell like it does coming out of our car and new other new diesel trucks- kind of sweet smelling and not burnt smelling. Then there’s older diesels without the SCR and DPF system, they smell Smokey and more burnt. If the car is idling or if I drive in first gear in a parking lot, I can smell the fumes coming in from my vents. Again, according to the dealer, it’s a diesel and that’s normal.

I’m trailing off- anyway. This is what I think is happening. Exhaust is escaping from the exhaust turbo which is causing a different reading from what ever various sensors are in place, to ensure the correct amount of air is passing through. 

What I believe is happening is the gap or crack in the exhaust is larger when cold, causing a loss in pressure that the engine calculates and accounts for by maybe dialing back fuel.

When the car warms up, again maybe two minutes down the road, it no longer does this. Possible due to thermal expansion.

Am I crazy? Is this really far off? I’m going to give it a shot at another dealer and see what comes about all of this 


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## MRO1791 (Sep 2, 2016)

Carminooch said:


> No issues starting. The car is a manual. I have my own far fetched theory...
> 
> There’s splattered soot on my turbo near the wastegate. It’s been like that since 1000 miles in. I’ve raised the issue with the dealer and they told me again, that it’s normal.
> 
> ...


Well, all 3 of my Gen 2, 1.6L have some soot splatter on that turbo actuator, and one of mine is a manual. I don't get that hesitation as you describe on any of them. I also do not notice exhaust smell inside the car either. Now, somewhere on this site a person had a bad turbo, and it was replaced under warranty. A sooted up turbo might be more sluggish when cold and be a bit less so when warm, and that really high cold oil pressure tells me the bearing clearances are really tight on these cars. 

I think it is most likely turbo related, or even an exhaust leak that might be something similar to what you describe. 

Now good luck getting a servicing dealership to fix it. That seems to be a growing challenge these days.


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## MRO1791 (Sep 2, 2016)

Oh, can you post a picture of your soot spatter? Some ability to compare that to what I see would be helpful to see if that is normal. Have multiple cars is helpful to me to determine what is normal or not, as I can directly compare them. If I can get a decent picture of one of mine, I'll try to post that too.


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## Carminooch (Mar 23, 2018)

Sure I’ll try to get a shot tomorrow of the soot. Thanks for the input 


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## TDCruze (Sep 26, 2014)

I have never smelt the typical old diesel exhaust (pre DPF) smell from my gen 2. Not even when in the garage. Never should you smell it coming through your interior vents. 

I believe there was another member that had a turbo replaced under warranty for this soot / exhaust leak from the turbo wastegate. They also reported smelling exhaust in the interior.


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## MP81 (Jul 20, 2015)

Reason I asked about the starting and the mileage is because right around 50k is when the Gen 1's seemed to start showing signs of the EGR getting sticky.

I cleaned ours at about 50k, and it looks like it's about time now around 100k.


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## Barry Allen (Apr 18, 2018)

Carminooch said:


> As the title states, the car tends to hesitate when trying to drive for the first mile and then it clears up. It happens only under medium to low throttle.


Mine does this as well during winter weather, say below 30 degrees. I had one tank of fuel that I considered to be less-than-desirable because cold starts would have it misfiring for the first 20-30 seconds of driving when I used any throttle beyond idle. It cleared up with a fresh tank of fuel, but I know the hesitation you're talking about.

Just ignore it. Cars will never run perfect when they are cold started. Drive it lightly for a couple minutes and once the temperature gauge starts to rise from the very bottom it's ready to go for anything.


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## TDCruze (Sep 26, 2014)

Poor fuel quality would definitely give you hesitation and a feeling of poor operation. As for the soot around the wastegate I snaped a picture of mine at nearly 30000 mi. There is a bit of soot in the area. I think this is normal as it is not a perfect seal. You should not however smell diesel fumes in the cabin. You may have a leak at the dpf or exhaust manifold?


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## Carminooch (Mar 23, 2018)

TDCruze said:


> Poor fuel quality would definitely give you hesitation and a feeling of poor operation. As for the soot around the wastegate I snaped a picture of mine at nearly 30000 mi. There is a bit of soot in the area. I think this is normal as it is not a perfect seal. You should not however smell diesel fumes in the cabin. You may have a leak at the dpf or exhaust manifold?
> 
> View attachment 283681


The soot has been increasing since new. I keep the car very clean but the soot returns always. When the engine is running, I can smell that old school pre-DPF/SCR exhaust smell with my face a a half a foot away from the turbo while idling. It’s the same smell that comes in my vents if I drive in 1st gear in a parking lot. And not the same smell that exhausts after it’s been treated.

When I bring my car in on Tuesday, are there bulletins or anything I can reference to try to plead my case to the service manager? I don’t want to keep owning this car if the dealer is failing to understand an exhaust leak at the turbo not only goes against strict emissions laws, it could be damaging to the longevity of the vehicle



















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## TDCruze (Sep 26, 2014)

You have a significant leak from your wastegate! I have never cleaned mine and it is much less messy.

It will not effect the car performance or risk damaging anything, but it is a health concern with the fumes and soot.

If your normal dealership will not do anything. Try another if possible. Or push yours harder.

Complain about the diesel exhaust odor in the cabin and if they still won't try to fix open a claim with GM customer care.


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## BodhiBenz1987 (Jan 13, 2018)

Carminooch said:


> The soot has been increasing since new. I keep the car very clean but the soot returns always. When the engine is running, I can smell that old school pre-DPF/SCR exhaust smell with my face a a half a foot away from the turbo while idling. It’s the same smell that comes in my vents if I drive in 1st gear in a parking lot. And not the same smell that exhausts after it’s been treated.
> 
> When I bring my car in on Tuesday, are there bulletins or anything I can reference to try to plead my case to the service manager? I don’t want to keep owning this car if the dealer is failing to understand an exhaust leak at the turbo not only goes against strict emissions laws, it could be damaging to the longevity of the vehicle
> 
> ...


One of the problems I've had with dealers and my own issues is that it seems once they get told something is "normal" they extend that conclusion over everything. I.e., they're told it's normal for some soot to appear in that area, and no one knows what "some" is so they just say it no matter how much soot is there. Your leak looks like the one I had that was NOT normal. I had my DPF replaced (because of frequent regens after the dealer put the wrong oil in my car) and when I got it back with the new DPF the exhaust smell was horrid ... I thought maybe it was residual grease from the job burning off or something on the new part but after a few days of it not getting better I looked and there was soot like yours ... only mine was sort of finer and more thinly spread, but all over. I investigated further and the seal between the turbo and DPF was clearly crooked and not sealing. Yet the dealer had test driven it and gave it back to me in this condition. I took it back and they found the DPF neck had some manufacturing defect and it wouldn't seat so they had to replace the DPF again. Fumes and soot stopped. I would take yours to another dealer. Normal is a spectrum and at some point a symptom is off it. GM needs to get their #[email protected]* together in realizing that point exists.


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## MRO1791 (Sep 2, 2016)

I should be doing an oil change on mine tomorrow to get some pictures. It's not as clean as the first pictures, and not as sooty as the OP pictures. 

Could not agree more about GM trying everything that they can to avoid fixing things correctly. Basically everything that has needed repairs was some kind of hassle. Everytime.


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## HondaTech2016 (Apr 20, 2017)

My '17 auto sedan has had the sooted turbo since almost new and I dont believe I've ever had this issue. Definately no smells inside, over 70k miles currently and have never taken the turbo issue to the dealer.


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## Scott205 (Aug 11, 2016)

I am thinking three think you need to check/deal with. First a bit of water in your gas, some Iso-HEET ought to fix that, and won't hurt either way. Next I would pull out my spark plugs. There is a chance that they have been mis-gapped. I highly doubt if you are getting enough heat expansion if it is 60 degrees outside to fill any anything but the tiniest of gaps, and if you had one, it would either whistle or squeak like a bad bearing. Most likely if you do have a leak it would be in the manifold, or a seal. but moisture in the ignition system could also explain it.


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## MP81 (Jul 20, 2015)

Diesels have a water separator in the fuel filter, so water in the fuel isn't likely.

No spark plugs or ignition system, again, due to being a diesel.


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## Carminooch (Mar 23, 2018)

I got the car back today. They checked the fuel pressure and for any codes and nothing. They did however feel the hesitation I refer to. They showed me a bulletin stating the big exhaust leak at the turbo charger is “normal operation”. 

They want me to run through my tank of fuel, tank up at a BP or brand name fuel station, and see if it persists.

Interestingly enough I drove home on neighborhood roads and had a regen. I thought this would only happen on the highway at a certain speed. I heard the fans running after I parked so I got curious and restarted the car and whoooo boy that exhaust is HOT during a regen. That’s the first time I experienced one that I noticed.

After this tank of fuel, I’ll keep you updated on what happens 


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## MRO1791 (Sep 2, 2016)

It's not the fuel. Dealerships and GM try to avoid expensive warranty repairs. Your leak seems excessive. I didn't get pictures of mine yet.. it was dark raining for my oil change. 

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## MRO1791 (Sep 2, 2016)

Ok, pictures. Somewhere between the cleaner first pics and the OP pics. 20,042 miles.


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## Barry Allen (Apr 18, 2018)

Carminooch said:


> They want me to run through my tank of fuel, tank up at a BP or brand name fuel station, and see if it persists.


I think it's pretty hard to get bad fuel. Diesel fuel quality in the USA had entirely stabilized after the 2007 switch to ULSD because of the fairly stringent standards that are now required to meet the ASTM specifications. Unless it's a specific outlier, every fuel station is getting their diesel fuel from the same refineries. BP, Shell, Exxon, etc. are all sourcing their fuel from the distributor that is loading it into tanker trucks for delivery, and the only difference in most cases is an additive package. So the smaller mom-and-pop gas stations are buying the same fuel and maybe not putting additives in the fuel for whatever reason. Either way, it's all the same fuel. There isn't much variety for the dealership to say they want you to buy from BP or other brand names other than maybe you should buy fuel from stations that have a good turnover of fuel so you get fresh fuel.


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## MRO1791 (Sep 2, 2016)

MP81 said:


> Diesels have a water separator in the fuel filter, so water in the fuel isn't likely.
> 
> No spark plugs or ignition system, again, due to being a diesel.


Sure details.... But if he could find spark plugs, it would certainly be a problem!


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## BodhiBenz1987 (Jan 13, 2018)

Carminooch said:


> I got the car back today. They checked the fuel pressure and for any codes and nothing. They did however feel the hesitation I refer to. They showed me a bulletin stating the big exhaust leak at the turbo charger is “normal operation”.
> 
> They want me to run through my tank of fuel, tank up at a BP or brand name fuel station, and see if it persists.
> 
> ...


It has a few factors that allow to "decide" whether to proceed with a regen. I have had them start/continue/complete on back roads and even stop and go traffic ... they just take longer to finish since the process kind of pauses at a stop/low speed. If it's on the colder side out and you're in the middle of a regen, and you stop at a stoplight, you can feel the idle "bump" itself every couple of seconds to keep exhaust temps up so it can resume the regen after you start again. 
I think the concerning aspect of the exhaust leak isn't the visible soot but the smell. It's hard to quantify the amount of soot that's acceptable down there, but it shouldn't stink to the point of coming in A/C vents. Mine has a smell occasionally when it gets hot in stop and go traffic, and the windows are down, if I focus on it, but it's nothing compared to the smell I had when they put that seal on wrong and it was really leaking. I would call GM at this point and emphasize you are concerned about the smell.


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