[Chris Larsson]

Dears,
I bought a used 2017 zl1 two weeks ago. The car was doing fine boost is fantastic and the car is really amazing.

During the first week I saw the check engine light in the morning but couldn't read it and it disappeared in the afternoon.

This week, the engine was not giving full power. I don't feel the supercharger engagement. Yesterday, check engine light was flashing when I tried full power. Then, the light disappeared. I checked the values from an obd2 scanner and I'll share it in this thread.

Also, I hear sound like grinding/crushing in the hood when I try to accelerate.

How should I start the troubleshooting?

[Chris Larsson]

Attached some sensors and error codes.

[ZLRob]

Jesus Christ...

If you have a P0300, start there. You may also want to state the miles you have on it too. Given that you have a P012B that could indicate supercharger issues as well. No way to really know until you get started taking it apart.

If your plugs appear wet then you have a bad direct injector or several. This could get ugly really fast. If that appears okay then I would pull the blower belt off and manually spin the supercharger pulley by hand. If you hear anything other then the normal sound of the rotors turning (the crushing sound or marbles in a can that you hear when you try to give it gas) then you got bad supercharger internal bearings. It may require a rebuild or in some really bad cases, a whole new supercharger unit.

If you need injectors I got some OEM take offs from my own car that were in stellar condition prior to being pulled off. I upgraded and went larger. I'll try to help out however I can, but like I said this could get ugly REALLY fast given that that crushing sound you are hearing when you give it gas is concerning.

[2023_ZL1-AUTO]

I had a random P0300 pop up twice since I've had the car. Interesting enough it also set off ever other code the computer could generate. As ZLRob said, start with that. Check your coil pack connectors and your plug wires? Mine was random, not reason behind it that I was able to find.

[Chris Larsson]

Originally Posted by ZLRob

Jesus Christ...

If you have a P0300, start there. You may also want to state the miles you have on it too. Given that you have a P012B that could indicate supercharger issues as well. No way to really know until you get started taking it apart.

If your plugs appear wet then you have a bad direct injector or several. This could get ugly really fast. If that appears okay then I would pull the blower belt off and manually spin the supercharger pulley by hand. If you hear anything other then the normal sound of the rotors turning (the crushing sound or marbles in a can that you hear when you try to give it gas) then you got bad supercharger internal bearings. It may require a rebuild or in some really bad cases, a whole new supercharger unit.

If you need injectors I got some OEM take offs from my own car that were in stellar condition prior to being pulled off. I upgraded and went larger. I'll try to help out however I can, but like I said this could get ugly REALLY fast given that that crushing sound you are hearing when you give it gas is concerning.

Thanks ZLRob …
Mileage is 100k.

[KingLT1]

Originally Posted by ZLRob

Jesus Christ...

Start by addressing the misfire code. Check the plugs and wires. Probably time to just go ahead and change them with 100k miles. Next step is injectors if you still have a misfire. Normally if injectors are failing you will see it in the long-term fuel trims but not always. The pull blower belt and turn supercharger by hand as previously mentioned. Probably time for new belts and hydraulic tensioner. 100k miles means it time to do a full service if nothing has been done yet.

[Megahurtz]

Intake temp B1S3 is over 200F. I would check your supercharger intercooler circuit for air bubbles, failed coolant pump or if it has any coolant in it at all. A more robust scanner tool like HPTuners, while monitoring the correct PID's, would show a much better picture of what could be wrong.

Doesn't hurt to check your plugs and wires as mentioned, but it isn't typical they go bad in the manor described. Multiple misfires make me think you have a fuel delivery issue or a blower that has no coolant in it and the ECU is pulling as much power as it can.

[ZLRob]

Originally Posted by Megahurtz

Intake temp B1S3 is over 200F. I would check your supercharger intercooler circuit for air bubbles, failed coolant pump or if it has any coolant in it at all. A more robust scanner tool like HPTuners, while monitoring the correct PID's, would show a much better picture of what could be wrong.

Doesn't hurt to check your plugs and wires as mentioned, but it isn't typical they go bad in the manor described. Multiple misfires make me think you have a fuel delivery issue or a blower that has no coolant in it and the ECU is pulling as much power as it can.

Damn that's a good eye man. I didn't even catch that when I initially looked over all of the smorgasbord of information that he showed there!

[KingLT1]

Originally Posted by Megahurtz

Intake temp B1S3 is over 200F. I would check your supercharger intercooler circuit for air bubbles, failed coolant pump or if it has any coolant in it at all. A more robust scanner tool like HPTuners, while monitoring the correct PID's, would show a much better picture of what could be wrong.

Doesn't hurt to check your plugs and wires as mentioned, but it isn't typical they go bad in the manor described. Multiple misfires make me think you have a fuel delivery issue or a blower that has no coolant in it and the ECU is pulling as much power as it can.

Good catch...

[Chris Larsson]

Thanks guys for the insights.

I took the car to the dealer. They proposed to start by changing the SC pressure sensor along with ECU programming and injectors cleaning. It sounds like a lazy plan as they didn't confirm if the sensor is bad or not. They want to charge $700 for everything.

[arpad_m]

Doesn't sound like that work would address the potential cooling problems. At the very least, they should burp the S/C cooling circuit. You'd be much better off installing a reservoir, like many others with the LT4 did in this very forum.

[RobZL1]

Dealers. Good grief.

[ZLRob]

I don't know how many more times I'm going to have to say Jesus Christ in one thread for different reasons. Not to you, but with what's going on just to clarify.

So let me start by saying this... Jesus Christ.

Getting that out of the way, if you have air in the supercharger cooling loop it will cause misfires, it will kill power, it will kill timing, it will cause a lot of runability issues, many of which you are describing here..

Do yourself a favor and get a Cordes or a Moroso LTR reservoir first and foremost. If you can't install it then find someone who can or is willing to for you. It's not hard to set up at all but does require some mild handiness that I'm not sure you have based on the thread so far.

Do that and then report back. For the moment, send the dealer to hell. They are scam artists and got a bunch of untrained, minimum wage paid monkeys working on all of the vehicles that roll through.

[Joshinator99]

Originally Posted by ZLRob

I don't know how many more times I'm going to have to say Jesus Christ in one thread for different reasons. Not to you, but with what's going on just to clarify.

So let me start by saying this... Jesus Christ.

Getting that out of the way, if you have air in the supercharger cooling loop it will cause misfires, it will kill power, it will kill timing, it will cause a lot of runability issues, many of which you are describing here..

Do yourself a favor and get a Cordes or a Moroso LTR reservoir first and foremost. If you can't install it then find someone who can or is willing to for you. It's not hard to set up at all but does require some mild handiness that I'm not sure you have based on the thread so far.

Do that and then report back. For the moment, send the dealer to hell. They are scam artists and got a bunch of untrained, minimum wage paid monkeys working on all of the vehicles that roll through.

Mostly true too, unfortunately (about the dealer part..not all of course, but my GM dealer experience has been very poor which is why I’ve avoided them for the last 7 years).