# Misfires on tune



## JLL (Sep 12, 2017)

Thebigzeus said:


> I have noticed I have sometimes many misfires over a tune log. I have been told these are normal for the 1.4l. I am wondering how normal they actually are. Anyone want to compare? This is over a 10 minute or so log.
> 
> View attachment 290397


I don't have a log to share as I recently lost my logs when when I reloaded the OS on my PC. However I can attest to random misfires during logs. Normally it's only 3-4 at a time until the misfire counter resets. It happens for me on 93 and E85. It's nice to know it's not just me.

Is that EFILIVE?


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## Thebigzeus (Dec 2, 2018)

JLL said:


> Is that EFILIVE?


Yes


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## MP81 (Jul 20, 2015)

Did you guys switch to a colder plug? It might not be necessary, since your engine is already boosted - but it might be enough of a change that it could help.

When I put the supercharger on my Cobalt, I went two steps colder - but that was going from an NA engine to 15 psi of boost crammed into it.


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## Thebigzeus (Dec 2, 2018)

MP81 said:


> Did you guys switch to a colder plug? It might not be necessary, since your engine is already boosted - but it might be enough of a change that it could help.
> 
> When I put the supercharger on my Cobalt, I went two steps colder - but that was going from an NA engine to 15 psi of boost crammed into it.


Yeah and I ended up with unburned fuel in the cylinders and almost completely clean pistons where I could read the laser etched code.


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## JLL (Sep 12, 2017)

MP81 said:


> Did you guys switch to a colder plug? It might not be necessary, since your engine is already boosted - but it might be enough of a change that it could help.
> 
> When I put the supercharger on my Cobalt, I went two steps colder - but that was going from an NA engine to 15 psi of boost crammed into it.


I didn't. I run 50 - 82% ethanol, which burns colder than gas. I have 0 KR.


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## Cruzin2011 (Jul 5, 2020)

I don’t have any logs to share but I haven’t seen any in the 5 or so logs I made during tuning for my bigger turbo. I’m only running 20PSI though on 93 octane


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## MP81 (Jul 20, 2015)

JLL said:


> I didn't. I run 50 - 82% ethanol, which burns colder than gas. I have 0 KR.


Well, and E85 is 105 octane, so you have built in knock-resistance to begin with.

That all said, my gaps had opened up as of the last year and I was getting a fair amount of misfiring at the top of the rev range at WOT. You're not supposed to regap iridiums...but I did anyway, mainly to test if that was the issue - it was. That, combined with the new fuel pump/tank/filler replaced under unlimited mileage/time special coverage, made the car back to what I know I built 11.5 years ago.


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## JLL (Sep 12, 2017)

MP81 said:


> Well, and E85 is 105 octane, so you have built in knock-resistance to begin with.
> 
> That all said, my gaps had opened up as of the last year and I was getting a fair amount of misfiring at the top of the rev range at WOT. You're not supposed to regap iridiums...but I did anyway, mainly to test if that was the issue - it was. That, combined with the new fuel pump/tank/filler replaced under unlimited mileage/time special coverage, made the car back to what I know I built 11.5 years ago.


If my memory serves me right, doesn't the L61 have a compression ratio of 10.5:1? The LUJ has a compression ratio of 9.5:1.


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## Thebigzeus (Dec 2, 2018)

These are brand new ac Delco plugs. Still can’t figure out why the brk 8’s were leaving unburnt fuel. Tried all sorts of gaps with them too.

Does one assume the misfires are due to detonation? They don’t seem to occur over WOT, rather mid range throttle and some right after you let off of WOT.


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## Cruzin2011 (Jul 5, 2020)

One thing to mention which I know you covered but for others that may read this is Tim from ZZP told me if I start getting random misfires was to check the spark plug gap as the 1.4’s are known for widening the gaps on the plugs. I’m running NGK’s one step colder.


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## MP81 (Jul 20, 2015)

JLL said:


> If my memory serves me right, doesn't the L61 have a compression ratio of 10.5:1? The LUJ has a compression ratio of 9.5:1.


10.0:1


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## Thebigzeus (Dec 2, 2018)

Cruzin2011 said:


> One thing to mention which I know you covered but for others that may read this is Tim from ZZP told me if I start getting random misfires was to check the spark plug gap as the 1.4’s are known for widening the gaps on the plugs. I’m running NGK’s one step colder.


Yeah I went down as small as .025, didnt see a huge difference. Which specific model of NGK are those?


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## Cruzin2011 (Jul 5, 2020)

Thebigzeus said:


> Yeah I went down as small as .025, didnt see a huge difference. Which specific model of NGK are those?


BKR7e gapped at .028


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## Thebigzeus (Dec 2, 2018)

Cruzin2011 said:


> BKR7e gapped at .028


I see. I tried the EIX ones not sure the differences. Both 7 and 8. I thought 8 was one step cooler. You’re saying 7 is? My 8’s came out black and rich.


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## Cruzin2011 (Jul 5, 2020)

Thebigzeus said:


> I see. I tried the EIX ones not sure the differences. Both 7 and 8. I thought 8 was one step cooler. You’re saying 7 is? My 8’s came out black and rich.


My local parts stores didn’t have the NGK’s so I ordered mine from ZZP and selected 1 step cooler. They have tech article that covers spark plug recommendations for all the vehicles they support and have that number listed for the 1.4’s


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## JLL (Sep 12, 2017)

Thebigzeus said:


> I see. I tried the EIX ones not sure the differences. Both 7 and 8. I thought 8 was one step cooler. You’re saying 7 is? My 8’s came out black and rich.


I actually think 8's might be 2 steps colder. 7 I think is 1 step colder.


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## Cruzin2011 (Jul 5, 2020)

JLL said:


> I actually think 8's might be 2 steps colder. 7 I think is 1 step colder.


Could be


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## Thebigzeus (Dec 2, 2018)

JLL said:


> I actually think 8's might be 2 steps colder. 7 I think is 1 step colder.


No wonder mine had unburnt fuel! All the people here recommended them! I don’t remember the huge thread... it’s somewhere.


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## Cruzin2011 (Jul 5, 2020)

Thebigzeus said:


> No wonder mine had unburnt fuel! All the people here recommended them! I don’t remember the huge thread... it’s somewhere.


If you want I can pull one out tomorrow and let you know exactly what I put in there, I am pretty it was a 7 and not an 8









Spark Plug Recommendations and Gap


Car specific Spark Plug recommendations and general Spark Plug Tech information.




zzperformance.com





The article does mention the 7’s for our cars


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## Thebigzeus (Dec 2, 2018)

I’m fairly intrigued at this point.


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## Cruzin2011 (Jul 5, 2020)

Thebigzeus said:


> I’m fairly intrigued at this point.


I will pull one out tomorrow, I definitely went with the 1 step colder when ordering them from ZZP.


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## Thebigzeus (Dec 2, 2018)

Spark Plugs


Hey everyone, so it's time to replace my spark plugs, and I was searching through the forum for the best ones for my 2011 Chevy Cruze Eco (1.4l). I came across this thread: https://www.cruzetalk.com/forum/34-gen1-1-4l-turbo/21850-hesitation-gone.html So from what this guy says is that the copper...




www.cruzetalk.com





Hmm according to this 7 is stock heat...


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## Cruzin2011 (Jul 5, 2020)

Thebigzeus said:


> Spark Plugs
> 
> 
> Hey everyone, so it's time to replace my spark plugs, and I was searching through the forum for the best ones for my 2011 Chevy Cruze Eco (1.4l). I came across this thread: https://www.cruzetalk.com/forum/34-gen1-1-4l-turbo/21850-hesitation-gone.html So from what this guy says is that the copper...
> ...


I’ll pull one out when I wake up tomorrow as I’m certain ZZP only sells 1 and 2 step colder plugs and I definitely ordered 1 step colder, I could of sworn it was the 7’s but I’m getting up there in age so I could be wrong!


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## Thebigzeus (Dec 2, 2018)

Cruzin2011 said:


> I’ll pull one out when I wake up tomorrow as I’m certain ZZP only sells 1 and 2 step colder plugs and I definitely ordered 1 step colder, I could of sworn it was the 7’s but I’m getting up there in age so I could be wrong!


thanks! I’m not trying to imply anyone is wrong, just trying to get to the bottom of this. I have a feeling you’re actually right, because the 8’s seemed too cold resulting in the issues I saw.


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## Snipesy (Dec 7, 2015)

That’s fine.


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## Thebigzeus (Dec 2, 2018)

Snipesy said:


> That’s fine.


?


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## jblackburn (Apr 14, 2012)

6 heat range was stock for 2011's. It was too hot.
7 is the OEM heat range for most years.
8EIX were the recommended BKR Iridium plug because the BKR7EIX didn't run as well as the regular 7E nickel plug. They didn't run rich on the stock tune.

If you're seeing misfires with a tune, knock the gap down to .024".


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## Thebigzeus (Dec 2, 2018)

jblackburn said:


> 6 heat range was stock for 2011's. It was too hot.
> 7 is the OEM heat range for most years.
> 8EIX were the recommended BKR Iridium plug because the BKR7EIX didn't run as well as the regular 7E nickel plug. They didn't run rich on the stock tune.
> 
> If you're seeing misfires with a tune, knock the gap down to .024".


thanks, and the reason when I ran 8’s and had unburnt fuel? Any guesses? I imagine that’s a loss of power.


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## jblackburn (Apr 14, 2012)

Thebigzeus said:


> thanks, and the reason when I ran 8’s and had unburnt fuel? Any guesses? I imagine that’s a loss of power.


A common way to reduce in-cylinder temps on turbo engines is overfueling at WOT.


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## Thebigzeus (Dec 2, 2018)

Even worse gapped down to .024 

(over 15 minutes)


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## Thebigzeus (Dec 2, 2018)

Found this though on the o2 sensor wires when doing the work though. Thinking liquid electrical tape should fix it. Wonder if it’s adding to this problem.


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## jblackburn (Apr 14, 2012)

Thebigzeus said:


> Even worse gapped down to .024
> 
> (over 15 minutes)
> View attachment 290416


Are you seeing it happen at a specific RPM? Is the coil pack the original?


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## Thebigzeus (Dec 2, 2018)

jblackburn said:


> Are you seeing it happen at a specific RPM? Is the coil pack the original?


MSD pack.

RPM graph on top


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## jblackburn (Apr 14, 2012)

Thebigzeus said:


> MSD pack.
> 
> RPM graph on top



View attachment 290418

Hmmmm...looks like a lot are happening <2000 RPM...like 1800 or so? I always saw gap/coil pack failure issues in the meat of the powerband ~33-3800 RPM.

Could be a tune thing that needs revising, could be the car pulling power due to knock down that low...not sure. Mapping it with KR might be interesting to see if they correspond. Does the same happen on a stock tune?


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## Thebigzeus (Dec 2, 2018)

jblackburn said:


> View attachment 290418
> 
> Hmmmm...looks like a lot are happening <2000 RPM...like 1800 or so? I always saw gap/coil pack failure issues in the meat of the powerband ~33-3800 RPM.
> 
> Could be a tune thing that needs revising, could be the car pulling power due to knock down that low...not sure. Mapping it with KR might be interesting to see if they correspond. Does the same happen on a stock tune?


I am told by BNR time and time again this is normal, I just don't see how. 

With KR brought into play. Seems sometimes they do correspond quite often, but others they dont. Like the 2nd retard.


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## Cruzin2011 (Jul 5, 2020)

Thebigzeus said:


> thanks! I’m not trying to imply anyone is wrong, just trying to get to the bottom of this. I have a feeling you’re actually right, because the 8’s seemed too cold resulting in the issues I saw.


I pulled a plug and it is definitely an NGK 7... that is what ZZP sent me when I choose 1 step colder on their website.


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## Thebigzeus (Dec 2, 2018)

Cruzin2011 said:


> I pulled a plug and it is definitely an NGK 7... that is what ZZP sent me when I choose 1 step colder on their website.


Thanks, appreciate it!


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## Snipesy (Dec 7, 2015)

Thebigzeus said:


> ?


The misfire count.

The misfiring is detected by closely monitoring the crankshaft position sensor. Every ‘bang’ should create torque in a somewhat predictable manner, and if it doesn’t there is obviously a misfire.

However a lot of things affect the crankshaft, the road, the ac compressor, engine mounts, cv axles... All of these will trigger misfire detection. And when observing the misfiring counters while driving, this is what you are seeing.

In addition the engine is constantly adjusting things to detect how far it can more or less advance timing (and other things) until knocking occurs. This is how it adjusts for fuel. However as a side affect a misfire can be detected.


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## -loki- (Dec 13, 2019)

It does appear that the ecu is constantly tweaking... I wish it wouldn't have to heat up the cats before advancing the timing... losing so much MPG since it's cold out. 

*Zeus what do you run your plugs at? I've had pretty good luck with .025 so far... *


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## Snipesy (Dec 7, 2015)

-loki- said:


> It does appear that the ecu is constantly tweaking... I wish it wouldn't have to heat up the cats before advancing the timing... losing so much MPG since it's cold out.


It shouldn't be too bad?

Sometimes the tuning will hurt the catalyst warmup. And Hp Tuners nor EFI Live really has any of these settings to make it better. _I could be wrong but I have never seen them._


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## Thebigzeus (Dec 2, 2018)

-loki- said:


> *Zeus what do you run your plugs at? I've had pretty good luck with .025 so far... *


They were at .028, gapped to .024 today. Seems to run fine at both.


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## Thebigzeus (Dec 2, 2018)

Snipesy said:


> Sometimes the tuning will hurt the catalyst warmup.


Fine by me, I only dont have a front one.


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## Snipesy (Dec 7, 2015)

Thebigzeus said:


> Fine by me, I only dont have a front one.


That's another problem.... I dont really know how effective HP Tuners / EFI Live is at actually deleting the CAT programming.

Normally the car looks for the rapid change in O2 sensor readings to indicate the warmed up condition... But if those aren't there honestly I haven't a clue.


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## -loki- (Dec 13, 2019)

I dont have either cat... smells like a sport bike in the mornings during warm up.


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