[2023_ZL1-AUTO]

Sorry for this being a long and detailed post: I have a dumb question regarding bolts that require torqueing. I have a recent issue that seems to have a pattern to it. It has to do with when the weather air temperature is colder vs warm/hot on average.

Background behind why I’m asking this question and could it be related to the issue: When I last had my supercharger off my car, was when I had to back out a snapped off bolt, Oct-4 2023. That day, it was extremely hot here in Columbus. It was 86° when my brother in-law and I were working on the car. We torqued all the bolts to spec for the supercharger and the lid. After we completed the work, we took it to get dinner and all was good! Afterwards, off and on I drove the day another 15+ different days and the car ran great no issues. Then, mid-November I parked and covered it and didn’t wake it up again until mid-February when we had some nice weather (forgot to keep it on a battery tender… that was fun!).

Anyway, I drove my ZL1 when the air temp was 42° - 63° over three days and 15 different trips here and there, no issues. After that, drove it again when the air temp was 34° - 40°, I made a few trips and got a check engine light on the last trip, codes P0171 & P0174. I cleared the codes with my Banks i-Dash Data Monster Gauge and parked the car until the next time the weather got nice.

Weather got nice and I drove it again over four days, the temps were 48°- upper 60°. The first trip, the check engine light was still on, I cleared codes again. But, the very next trip it was off and didn’t come back on. I took it out again on a colder day, 30° - 42° and the check engine light came on after like the 3rd trip and the codes were the same, I cleared the codes and parked it again. This week the weather has been crazy nice! So, Sunday – Wednesday I’ve driven the car a lot! But, the first trip on Sunday the check engine light was on, so I cleared codes again. Since clearing the codes all trips (20+) thereafter, no check engine light.

So that brings me to my dumb question: Could I have a vacuum air leak post mass airflow sensor due to the colder day’s vs hotter days? Could this be happening because when we the bolts were torqued last time, it was 86°. Now on days it’s cold the torques change? And on days it’s warmer the torque is back to correct? I just don’t know why on cold days only the check engine light comes on vs days it much warmer.

Any ideas would be appreciated.

Thanks

[CalgaryZL1]

Did you replace all the bolts holding down the SC with new ones? They are one use bolts, and if you didn’t replace them and torqued them to the original spec, maybe some of them are broken and you are getting an air leak.

[2023_ZL1-AUTO]

Originally Posted by CalgaryZL1

Did you replace all the bolts holding down the SC with new ones? They are one use bolts, and if you didn’t replace them and torqued them to the original spec, maybe some of them are broken and you are getting an air leak.

Yes, since I broke off a bolt, I bought a complete new bolt and gasket kit. All old was thrown away. This weekend I plan on doing a air leak test with my smoker, this is how I found the leak last time, I had a PCV hoses that had popped off. Hmmm... I should actually check that hose again !

[2023_ZL1-AUTO]

Need to a detail to the issue I originally posted up top. So, my car was tuned by Ted at JRE for E60. But, I noticed the times I drove my car and the check engine light came on. My alcohol reading was at E30 and then again at E43. Could this have something to do with the above issue and do I always need to be at E60 if that's how my car was tuned?

Thanks

[WhiteMale]

I just read a guy was having misfires with Ethanol at cold temps and or low RPM something like it has harder to light at those temps but E30 and 43 seem to have enough unleaded to not have that problem.

[2023_ZL1-AUTO]

Originally Posted by WhiteMale

I just read a guy was having misfires with Ethanol at cold temps and or low RPM something like it has harder to light at those temps but E30 and 43 seem to have enough unleaded to not have that problem.

I can data log and see what I come up with, it's worth a look! Thanks WM !

[WhiteMale]

What causes P0171 and P0174 at the same time?
When your powertrain/engine control module receives a reading that indicates there's too much oxygen and the ratio is incorrect, it sends an error code P0171 or P0174. Depending on the problem, it may send both codes if the issue is causing a lean condition on both engine banks.

[KingLT1]

Check all your connections from the throttle body to the cai. Also check your catch can connections/pet cock if you have one.

[2023_ZL1-AUTO]

WhiteMale & KingLT1 Will do !!! and will report back!!!

[2023_ZL1-AUTO]

KingLT ! Spot on regarding the petcock valve being open! It was screwed inward vs outward (It looks wrong!!!!) I blew into the end of the value and the air passed right through. I then twisted it outward and did the same, but that time no air would pass through! I checked all other hose clamps etc. and nothing all seemed ok! Thanks !!!!!!

[KingLT1]

That will do it...if left open it will cause a vacuum leak and you will get the lean codes on both banks.