2015 ZL1 knock? Conclusion @ 4/27/15

[TommyTheCat]

Originally Posted by angryBits

Update:

I got a call from my service advisor today.
They're resending their statement that I have bad gas.
Now they're saying they had "another car like mine" come in with a noise at 3k rpm and they determined it to be injector noise. Therefore my problem is injector noise. Come pick up your car. ... ... ... No, that makes no sense. Remember the part about, it happens when my car enters boost, not at a specific RPM. Remember the part about the OBD2-Reader says there's knocking going on? What does that have to do with a noisey injector at a certain RPM? Nothing. Absolutely nothing. They're just trying to get me to go away.

If you want to tell me, "Sorry the car knocks with Cali 91 gas and there's nothing we can do" then fine, but don't lie to me or try to tell me its something completely unrelated, injectors? The service guy I'm working with is actually very nice and honest -- I don't blame him at all, he's just telling me what they tell him and he agrees with me that its not a good fit. So he's going to call me back with the General Manager on the phone with him. I'm not sure what the General Manager can do as he probably doesn't know anything about cars. I'm thinking he's just the muscle that is supposed to shut me down and accept the situation but I won't -- not unless they admit the car knocks and its not supposed to. Then they can tell me they'll work with GM to come up with a new tune for the car, which may be BS but thats on them whether or not they come through.

This is such BS.

My wife has already given me the go-ahead on getting another car. I may take her up on that offer. I love the car, but I want an engine that doesn't knock -- that's not asking to much, that should the minimum expectation for any car.

F#$%!

go to another dealer

[angryBits]

Originally Posted by TommyTheCat

go to another dealer

My dealer talked to GM and this is what GM told them. I'm not sure another dealer will have any more luck.

[ProchargedSS]

Originally Posted by angryBits

Yep. At this point I'm officially giving up on the dealer's willingness to help me.

I think I'll try the 100 octane gas not too far from here.

Worth a try.

[Nor Cal ZL1]

Dude a few things.
1) is the car even broken in yet? Is it using oil?

2) Abel, take it there for your dealer needs. This would be my next move. They know thier performance cars. They will leave you with the answer if the car will damage itself or not. Request Chad as the tech if possible.

3) Starkweather in turlock. If your going to tune it. Personally I would drive it stock for 10,000 miles before this to shake out any issues. Also a 2nd opinion if damage will occur.

4) Sunol super stop high octane.

5) The highest mileage Z I know of is burning Cali 91. He is over 70,000 miles. Car is also Abel serviced, and stock. I dont notice any knocking on mine but my exhaust is a bit louder than stock. Im at 15,000 and ready to mod.

6) Don't worry if you mod it, these cars are very strong.

[JD_Alaska]

Knock is confirmed as the sound your hearing?

[1KillerSS]

Honestly, GM says its normal, and its clearly not, drive it till it blows up and get it warranted. Obviously its been documented more than once. I

I am confused because you talk about not wanting to void your warranty with a tune, yet you talk about modding your car and making more power, anything you do to that car to include a CAI is technically voiding your warranty....

I understand your a software engineer, and seem to be a pretty smart guy, I am wondering why you haven't figured it out yourself since you say you know exactly how the system works. Not to slam you or get your feathers ruffled, or even come across as an ass. If I seem that way them please forgive me, thats not my intention. There have been some great suggestions and advice here Z06 knows his stuff, his comments are direct and to the point, also they are rarely inaccurate. Why havent you followed them?

FYI knock can be caused by something as simple as a heat shield rattling, not saying thats what is causing your problem but my point is that a knock sensor will pick up stuff like that.

Try the torrco. If nothing else it will either verify or disprove.

We are all arm chair quarterbacks, when it comes to trying to help, take it to a real dealership as suggested that has a performance background. GM is only as good as the information that there service department is plugging into them.


IMO, personally once GM co signs the dealerships bullsh!t, take the car and drive it till it explodes and make them give you a fresh one. That or sell it.

[Bigtime53]

Originally Posted by angryBits

Yep. At this point I'm officially giving up on the dealer's willingness to help me.

I think I'll try the 100 octane gas not too far from here.

AMEN!!!

[Vroom]

You need to take it to Abel in Rio Vista. All dealers are not the same. I've had every dealer in the bay area screw me at one point or another, so much so, that I drive over an hour to get their help.
For instance, when the Dublin dealer told me their hands were tied and to go drive the car and if it breaks, they'll get GM to fix it. The GM response team called me separately and told me I could take it to another dealer. GM explained that it wasn't that they wouldn't fix a broken car, it was the dealer that didn't want to take the risk of tearing the car down since they don't get paid unless they find the problem.
So I took it to Rich at Abel and he immediately heard the problem, agreed it wasn't normal, took on the risk of figuring it out knowing they wouldn't get paid if they failed, and then fought for me to get a new engine. They'll give you the honest truth about your car. If they say its fine and normal, then it is.

Other option is to just drive it and wait for it to break. You have a 100k warranty and if you have a problem, it will definitely break by then.

And it blows my mind that every other post is an advertisement for Torco. I have 83k miles, only use 91 and have no knock.

[Nor Cal ZL1]

Originally Posted by Vroom

You need to take it to Abel in Rio Vista. All dealers are not the same. I've had every dealer in the bay area screw me at one point or another, so much so, that I drive over an hour to get their help.
For instance, when the Dublin dealer told me their hands were tied and to go drive the car and if it breaks, they'll get GM to fix it. The GM response team called me separately and told me I could take it to another dealer. GM explained that it wasn't that they wouldn't fix a broken car, it was the dealer that didn't want to take the risk of tearing the car down since they don't get paid unless they find the problem.
So I took it to Rich at Abel and he immediately heard the problem, agreed it wasn't normal, took on the risk of figuring it out knowing they wouldn't get paid if they failed, and then fought for me to get a new engine. They'll give you the honest truth about your car. If they say its fine and normal, then it is.

Other option is to just drive it and wait for it to break. You have a 100k warranty and if you have a problem, it will definitely break by then.

And it blows my mind that every other post is an advertisement for Torco. I have 83k miles, only use 91 and have no knock.

Thanks for checking in. I have told him to take it to Abel on more than one occasion. Maybe now that will happen.

[angryBits]

Originally Posted by Nor Cal ZL1

Dude a few things.
1) is the car even broken in yet? Is it using oil?

Car is at 2k miles. I'm "technically" past break-in but typically these cars are still breaking in up to 5k+

Originally Posted by Nor Cal ZL1

2) Abel, take it there for your dealer needs. This would be my next move. They know thier performance cars. They will leave you with the answer if the car will damage itself or not. Request Chad as the tech if possible.

3) Starkweather in turlock. If your going to tune it. Personally I would drive it stock for 10,000 miles before this to shake out any issues. Also a 2nd opinion if damage will occur.

Will Abel do a custom 91 Octane Tune or do I have to do it at Starkweather? Would be nice if the dealer would do it

Originally Posted by Nor Cal ZL1

4) Sunol super stop high octane.

I can get 100 octane at a gas station in Redwood City. Kings Union 76

Thanks for your help

[angryBits]

Originally Posted by JD_Alaska

Knock is confirmed as the sound your hearing?

Confirmed.

[angryBits]

Originally Posted by 1KillerSS

Honestly, GM says its normal, and its clearly not, drive it till it blows up and get it warranted. Obviously its been documented more than once. I

The problem is that it wont blow up, it will just weaken my engine. I plan to mod it (and void the warranty) when I hit about 10k miles and I want to know the engine is healthy when that time comes.

Originally Posted by 1KillerSS

I am confused because you talk about not wanting to void your warranty with a tune, yet you talk about modding your car and making more power, anything you do to that car to include a CAI is technically voiding your warranty....

Technically I'm not voiding the warranty. Technically nothing "voids" your warranty, that is just a myth. GM must prove the failure is related to the modifications done to the engine. If they can't prove it, they must fix it under warranty.

In any case, I expect there is a great chance a warranty claim will be voided if I start modding which is why I want to wait until I have about 10k miles and trust the engine. This way I feel its less likely the engine will blow up leaving me with a large bill.

Originally Posted by 1KillerSS

I understand your a software engineer, and seem to be a pretty smart guy, I am wondering why you haven't figured it out yourself since you say you know exactly how the system works. Not to slam you or get your feathers ruffled, or even come across as an ass. If I seem that way them please forgive me, thats not my intention. There have been some great suggestions and advice here Z06 knows his stuff, his comments are direct and to the point, also they are rarely inaccurate. Why havent you followed them?

I know how the electronic hardware works, I know the rules the software must follow. I know that the software can be overwritten to include new fuel mappings. Anyone can do it, its just a EEPROM. I believe I have figured out how to fix it but I'm not skilled at "tuning" cars, I'd rather leave it to an expert. The fix is to tune the car to run on 91 rather than 93. I may lose a few HPs but thats fine.

As far as Z06's advice -- I agreed with everything except whether or not the software can be overwritten. I think he is right that the dealer will not do it. I think GM "can" do it but is unlikely. I suppose I do disagree with running Torco. I don't think thats a solution -- thats more of a bandaid. I don't want to spend $60k on a car and have to put $20 worth of torco every time I fill up. That's not what I paid for. This is GM's fault and they don't want to make the car run properly on Cali 91 gas which sucks for me so I have to take things into my own hands to make the car right.

Originally Posted by 1KillerSS

FYI knock can be caused by something as simple as a heat shield rattling, not saying thats what is causing your problem but my point is that a knock sensor will pick up stuff like that.

Heat Shield rattling doesn't cause knock, though it can cause a noise that sounds like knock. Though its unlikely the knock sensors would interpret that sound as knock and retard the timing. The knock or ping has a very distinct sound. When you hear it, you know its not a heat shield. It sounds more like the sound a paintball gun makes -- not from the bullet itself but from the compressed air rapidly filling the air lines. Its like a ... "fooom" noise about as fast as a finger snap haha, I don't know how else to describe it. Its the sound of two extreme high pressure fronts colliding over a span of milliseconds.

Originally Posted by 1KillerSS

Try the torrco. If nothing else it will either verify or disprove.

Everyone keeps saying that. Torco contains MMT -- I'd rather not mess with it. I do have access to 100 Octane Race Gas about 20 miles away. I'm fine with trying it out. In fact I'll probably just run with a 3:1 mix of 91 and 100 until I can get a permanent solution figured out -- that should work out to more than 93 octane. But thats a bandaid, not a fix.

Originally Posted by 1KillerSS

We are all arm chair quarterbacks, when it comes to trying to help, take it to a real dealership as suggested that has a performance background. GM is only as good as the information that there service department is plugging into them.

Yeah Abel Chevrolet is my next stop -- everyone says they're really good. Hopefully they do better than Fremont Chevrolet.

[angryBits]

Originally Posted by Vroom

GM explained that it wasn't that they wouldn't fix a broken car, it was the dealer that didn't want to take the risk of tearing the car down since they don't get paid unless they find the problem.

WOW... This is a real eye opener. This never occurred to me. Thanks!

[1KillerSS]

Originally Posted by angryBits

The problem is that it wont blow up, it will just weaken my engine. I plan to mod it (and void the warranty) when I hit about 10k miles and I want to know the engine is healthy when that time comes.



Technically I'm not voiding the warranty. Technically nothing "voids" your warranty, that is just a myth. GM must prove the failure is related to the modifications done to the engine. If they can't prove it, they must fix it under warranty.

In any case, I expect there is a great chance a warranty claim will be voided if I start modding which is why I want to wait until I have about 10k miles and trust the engine. This way I feel its less likely the engine will blow up leaving me with a large bill.



I know how the electronic hardware works, I know the rules the software must follow. I know that the software can be overwritten to include new fuel mappings. Anyone can do it, its just a EEPROM. I believe I have figured out how to fix it but I'm not skilled at "tuning" cars, I'd rather leave it to an expert. The fix is to tune the car to run on 91 rather than 93. I may lose a few HPs but thats fine.

As far as Z06's advice -- I agreed with everything except whether or not the software can be overwritten. I think he is right that the dealer will not do it. I think GM "can" do it but is unlikely. I suppose I do disagree with running Torco. I don't think thats a solution -- thats more of a bandaid. I don't want to spend $60k on a car and have to put $20 worth of torco every time I fill up. That's not what I paid for. This is GM's fault and they don't want to make the car run properly on Cali 91 gas which sucks for me so I have to take things into my own hands to make the car right.



Heat Shield rattling doesn't cause knock, though it can cause a noise that sounds like knock. Though its unlikely the knock sensors would interpret that sound as knock and retard the timing. The knock or ping has a very distinct sound. When you hear it, you know its not a heat shield. It sounds more like the sound a paintball gun makes -- not from the bullet itself but from the compressed air rapidly filling the air lines. Its like a ... "fooom" noise about as fast as a finger snap haha, I don't know how else to describe it. Its the sound of two extreme high pressure fronts colliding over a span of milliseconds.



Everyone keeps saying that. Torco contains MMT -- I'd rather not mess with it. I do have access to 100 Octane Race Gas about 20 miles away. I'm fine with trying it out. In fact I'll probably just run with a 3:1 mix of 91 and 100 until I can get a permanent solution figured out -- that should work out to more than 93 octane. But thats a bandaid, not a fix.



Yeah Abel Chevrolet is my next stop -- everyone says they're really good. Hopefully they do better than Fremont Chevrolet.

A CAI will most certainly void your warranty. You have altered it from its original design specs. While GM has to prove that that was the cause of the failure, in order to deny a warranty claim, that only means that that particular failure wasn't the cause, does not mean that other components are in the clear. I never meant to suggest that any mod will completely void all parts of GM's bumper to bumper or powertrain warranty.

The fix is not to tune the car, if the tune was at fault then all ZL1'1 would have the same problem, think about it. A tune can make it go away if its detonation created knock. But that doesn't necessarily mean that you have solved the original issue, you have just found an alternative way to make it not occur.

Of course the software can be overridden by GM, I think the implied message from him was that there is no way in hell they will do it for you. There is to much liability in it for them, let alone the expense of doing it, so in a way they can but they cant. Your being a little too literal. Its not like GM has a guy sitting at the office who is just going to custom right you a new tune because some dipsh!t tech cant figure out whats causing your knock, and again if it was a tune issue why does every ZL1 not have this issue, your a software engineer you should know that.

Actually the knock sensors can pick up something as simple as a heat shield rattling. I should have added, provided they are touching the engine, or a component attached to an engine. They are essentially a sensitive microphone, only they work a little differently. Anything that makes a noise can be picked up by your knock sensors (technically) Thats why there is a knock learn feature in the system, it essentially learns what is and is not actual knock. There is another system that will decide what to do with that knock once its been identified.

Try going to HPTuners website and download there software, its free and you can view samples of files identical to your own, you do need to be a customer to go to the tune repository but any one of us can email you a file to look at, you just cant make changes to it. Give it a try, your probably smart enough to be tuning in a week.


Again not to be a a$$hole here but you really seem to have it figured all out on your own, I have met a lot of people like you, and sometimes, sometimes I say, your to damn smart for your own good. The problem could be staring you right in the face but your so convinced that its a tune, you don't bother to look at the alternatives. I worked on a car for three days trying to find knock, it was a Toyota Supra, we were using AEM's engine management system, we had knock and couldn't tune it out no matter what we tried. My boss who was just like you swore that it was the way the previous tuner tuned it, and it was actually a heat shield touching the manifold.......