NSC5

From the early posts I saw these modifications on the C7 will cause a CEL from the rear O2 sensors without a tune so that indicates the conditions are beyond the system's ability to compensate.

Engineers who design cars have through education and socialization learned to look at them from the systems point of view. Owners who modify often learn the hard way that when you modify one part you are potentially impacting the entire system and had better consider this set of issues. It certainly isn't just cars. I restore vintage amateur radio gear which is often replete with owner modifications that improve performance on one parameter while creating many other problems that the proud modifier has chosen to overlook. It doesn't mean that things cannot be improved from what the factory provides but to achieve true improvement it will probably be more complex and expensive than originally expected.

Foosh

Yeah, we're all just guessing here. The OP doesn't seem to be aware of a tune, but that doesn't mean it's not there, and I feel bad for him because I don't think it's going to be happy news.

sunsalem

You're absolutely right.

I didn't realize mods were involved.
If GM decides they are the cause, the OP is SOL and will have to pony up for the repair.
In this instance it would be a shame because he doesn't seem to be fully aware of exactly what his car has been thru.

With an auction car, caveat emptor and all of that, which is why I would never buy one.
Hell, I wouldn't even buy a used car period.

Sailfun

Rules for buying used high performance cars.
1. Pre purchase inspection
2. No mods
3. Garaged entire life
4. Not smoked in.
5. Prior owner over 35.
These rules have served me well!

To the OP's original issue was the car ever driven in rain after the CAI was added?

NSC5

Any used performance car along with most pickups and specifically diesel pickups that still have a powertrain warranty would have to go through a trusted GM shop before I would buy one-it would need the same level of ECM scrutiny it would get if GM was investigating whether or not a powertrain failure was going to be under warranty coverage. But I expect most dealers won't be willing to do this level of checking prior to sale and once something happens it will be impossible to prove that the tuning occurred prior to and not after sale.

But this may soon be an issue of the past. The ECM GM is using on the current generation (2017 ownward) L5P diesel pickup is considered uncrackable by several firms who have provided tuning in the past. It is highly encrypted and also tied into the other controllers within the system so outside of the limited ability to "fool" it via spoofing some of the engine sensors any major modification would require a new stand alone ECM that is also programmed to communicate with the other encrypted processors used throughout the vehicle. It isn't good news for those who like to modify their vehicles but it is a reasonable response to avoiding warranty fraud AND keeping the EPA happy; a side benefit is later owners won't have to worry about the vehicle having been tuned.

red62vette

I have a Porsche as well and spend time on that forum. Those guys are always plugging in Cobb tunes that just boost the sh*t out of the turbos. Then they are surprised when they get error codes or blow up a tranny or transfer case. All of these cars are designed by huge teams of very skilled engineers with deep resources, yet people are willing to trust an ECU flash from some small shop with a few guys that probably has trouble making ends meet. To me it's completely unreal that people take this risk on such expensive and complex cars.

sunsalem

GOOD rules.

LT1pwrd'94

Wasn't driven in rain at all in the 3 weeks I've had it. I have another car for rainy days.. if the dealer won't help me with getting warranty coverage, I'm at least hoping the block is usable and damage is minimal. The failure occurred at less than 2000 rpms.

Obviously I'm hoping they'll help me though..

455230

Really?........GM doesnt have to prove anything......Their position will be that the modifications took the engine out of design parameters and they cant be responsible for the consequences.

Unless the dealer intends to commit fraud, they have no say in the matter.......

Go ahead and press for warranty coverage, but dont be surprised when it's denied.

pdiddy972

Ah, if only the poster who was suggesting that doing 0-140 acceleration runs in his Vette (another thread) with 5 tanks of gas wasn’t increasing the chances of failures.

JerryU

I'm afraid your only hope is you have a rocker arm or valve spring failure or something minor. Headers and no CATs would require a tune or have a CEL tripped for several reasons.

For GM to pay, a dump of the Computer has to be sent to them. Any alteration at any time, even if reversed, is recorded. As is an overrev in a downshift that occurred at an excessive rpm for the lower gear. With your M7 that could have occurred with the previous owner.

Good luck.

bigsapper

Young Chevrolet was a good choice. For many years, they sponsored the Lone Star Corvette Club. They also have (had?) a Corvette racing program. If they can work something out for you, they will.

449er

Good luck man, hope that it works out in the end

LT1pwrd'94

Engine was taken apart today. A valve spring broke, dropping valve into piston.. they sent computer info to GM and discovered that previous owner had in fact tuned it. Was also told my powertrain warranty has been voided. I contacted chevy customer service and was told that a customer relations manager would review everything and contact me.

Gonna see what a few local shops would charge for crate motor install, may look into good set of Pistons also and a fresh tune. Or just factory crate motor with factory manifold and tune. Will see who offers what..

pdiddy972

Maybe get one of the beast drop-in NA replacement engines with forged internals and a new clutch?

CP

Fixt it for ya.

Classic-Chevy-Guy

If purchased from a car dealer, wouldn’t it carry a 30 day warranty?

AttyVette

Sorry that happened to you..that stinks and I bet the original owner dumped the Corvette because he figured there would be a problem with the engine sooner or later. Praying GM will help you out but my dealings with them in the past with a Silverado truck we bought new and a Volt that's paint failed were less than satisfactory.

B&BVettes

Buyer beware!

DanZR1

I've been thinking this the whole thread. What lot doesn't offer a 30 day (at least) warranty on a late model car?