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Discussion Starter · #1 ·
Just started using torque a bit ago to watch my driving habits a bit closer. Don't think I have hit boost for 2 weeks now. Today had to ramp up a bit when pulling onto a 55mph stretch and at about 44mph it fell flat on its face knock sensor according to torque read out at 13! Idk what a lot of knock is but I hadn't had anything above 4.5 since I started using torque and that was due to a piss poor shift. Not sure how the computers work but is it possible that it was used to my featherfoot driving it had a panic attack due to recieving too much fuel? I was confused for sure it spiked one more time up to 7.5 as well when I tried to get it to happen again. Any thought or words of wisdom?
 

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What octane gas are you running? The Cruze's engine is designed for 91 octane (KRD code) so running on anything lower will result in knock retard going nuts on you. Also, we know that the 1.4T LUV engine has a phantom knock somewhere that no one has ever tracked down.
 

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Discussion Starter · #3 ·
OBwon I have been running 89 100% gas. I bumped up from 87 about a month ago and never had this problem with it. I also never hypermiler as much. Curious if it's possible my plugs are getting too hot from running lean now that I have been looking more into things. Typical readout for me is in the following pic.
 

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Discussion Starter · #5 ·
If you can't see it. I typically hold speed between 40-45 when I can and advance is around 25-27. By what I have read that could up the plug temp by 200-250°c. Not sure if predetonation could be the cause.
 

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I'll jump in and try help here. Tho im not sure what your looking into

So the knock is jumping under the condition described in OP. Did you noticed any stutter or was it still pulling smoothly?

I have tripped the a CEL for knock. I run 87 in the freezing months -40°F , but i gave it the beans on a near 0°F day and the ECU really cut the boost and CEL

These ECU's aggressively try to add timing for fuel effecienty, so its can run really hot,lean and effecient while cruzing. But when your on the power its suddenly correcting and pulling timing cause its learned to run it with high adv.

When you put your foot down its not a perfect transition either, its running in fuel economy script up into ~5psi boost, over that it switches to a WOT script that drops the fueling from 14.7 to 12ish and goes to the WOT timing table.
 

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I run 87 all the time, and aside from heatsoak at over 100F ambient, the car works really well. Especially if it cools below 75F.

The octane ratings are the same nationwide, however, gas gotten in the south definitely is different from gas in the north. More adjusted for the hot weather.

87 rating here might equal to 89 somewhere else.
 

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Discussion Starter · #8 ·
I'll jump in and try help here. Tho im not sure what your looking into

So the knock is jumping under the condition described in OP. Did you noticed any stutter or was it still pulling smoothly?

I have tripped the a CEL for knock. I run 87 in the freezing months -40°F , but i gave it the beans on a near 0°F day and the ECU really cut the boost and CEL

These ECU's aggressively try to add timing for fuel effecienty, so its can run really hot,lean and effecient while cruzing. But when your on the power its suddenly correcting and pulling timing cause its learned to run it with high adv.

When you put your foot down its not a perfect transition either, its running in fuel economy script up into ~5psi boost, over that it switches to a WOT script that drops the fueling from 14.7 to 12ish and goes to the WOT timing table.
That sounds about right. So if I reset the ECU my milage would most likely drop but wouldn't get so retarded. Just curious if I close my plug gap up a bit it will help I did delete the air box resonator and someone mentioned having to close gaps down a bit after doing that before. Guessing .032 or .030 instead of my .034 might help. Was running good for a few weeks maybe the humidity dogged it out
 

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I run 87 all the time, and aside from heatsoak at over 100F ambient, the car works really well. Especially if it cools below 75F.

The octane ratings are the same nationwide, however, gas gotten in the south definitely is different from gas in the north. More adjusted for the hot weather.

87 rating here might equal to 89 somewhere else.
While octane ratings are the same as they're all tested at a controlled temperature at a set altitude, the effectiveness of pre-detonation suppression varies with both temperature and altitude. I have to run 91 year round in Denver.
 

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What octane gas are you running? The Cruze's engine is designed for 91 octane (KRD code) so running on anything lower will result in knock retard going nuts on you. Also, we know that the 1.4T LUV engine has a phantom knock somewhere that no one has ever tracked down.
Just a side question: Are you referring to the RPO Code (KRD)? I was wondering about this earlier...


OBwon I have been running 89 100% gas. I bumped up from 87 about a month ago and never had this problem with it. I also never hypermiler as much. Curious if it's possible my plugs are getting too hot from running lean now that I have been looking more into things. Typical readout for me is in the following pic.
OBwon, maybe that will go better than Dr. Ober....<GRIN>
 

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Just a side question: Are you referring to the RPO Code (KRD)? I was wondering about this earlier...




OBwon, maybe that will go better than Dr. Ober....<GRIN>
Actually, the md are my first and middle initials.
 

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I've been called so many variants on OBWan over the years that I tend to ignore them. As for the tribbles, there is actually a post somewhere here that starts out "The Tribbles said..."
 

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That sounds about right. So if I reset the ECU my milage would most likely drop but wouldn't get so retarded. Just curious if I close my plug gap up a bit it will help I did delete the air box resonator and someone mentioned having to close gaps down a bit after doing that before. Guessing .032 or .030 instead of my .034 might help. Was running good for a few weeks maybe the humidity dogged it out
If you reset the ECU it will be back to where it was in 5 minutes
Shouldn't have a noticeable difference with spark gap and knock retard, I have to gap 0.020" for a solid spark, anything more and im getting misfiring at full boost ~3000 rpm.
 

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Discussion Starter · #15 ·
I think I'll closer the gaps up a bit tomorrow and check to see if they are running too hot. If that's the case I can bump up a heat range. Assume as the ambient temp climbs car will run even leaner. Just wanna squeeze the extra mpg with the opened gap but having episodes like the other day just pours gas down the tailpipe.
 

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Discussion Starter · #16 ·
Hoping this picture shows. Fuel trims have been increasing negative. This was holding speed at 42 mph. Seems a bit excessive -3.9 stft and -21.1 Lyft! Is this indicating anything out of order or just really lean? Wasn't hurting milage anyways DIC claimed 54 mpg and torque claimed 53.8.
 

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hoping this picture shows. Fuel trims have been increasing negative. This was holding speed at 42 mph. Seems a bit excessive -3.9 stft and -21.1 lyft! Is this indicating anything out of order or just really lean? Wasn't hurting milage anyways dic claimed 54 mpg and torque claimed 53.8.
Spark plug at 7 are most likely fine, dropping a heat range probably won't yield anything more then longer change intervals.
The gap of 0.28 is an excellent sweet spot for the stock cruze. Your probably getting -20% on your LTFT from the intake res delete, this is healthy amount of LTFT, especially with a res delete.
Should add Exhaust Gas Temp to your Torque page. My guess is your around 1300°F when cruising

I think your cruze is running as good as possible.
 

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Discussion Starter · #18 ·
Thank you Mark as far as duplicating the retard issue I have tried since and can't get it to happen. I'm guessing due to humidity it dogged out on me. As soon as I get anymore retard of over 5 again I will drop gap to .030
 
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