PIP4765: Engine Misfire And No Compression Due To Piston Damage

[WickedMom]

The G8 is not listed in the list of affected vehicles, but the L76 is.
I will upload the pictures tonight from home.

#PIP4765: Engine Misfire And No Compression Due To Piston Damage - Inspect For High Performance Aftermarket Accessories - (Jan 25, 2010)


Subject: Engine Misfire and No Compression due to Piston Damage - Inspect for High Performance Aftermarket Accessories


Models: 2007-2010 Cadillac Escalade
2007-2010 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007-2010 GMC Sierra, Yukon
2007-2010 Hummer H2
with Any of the Following V8 Engine RPO Codes:
L76, L77, L92, L94, L9H, LC9, LFA, LH6, LH8, LH9, LMG, LY2, LY5, LY6, or LZ1 -------------------------------------------------------------------------------

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may complain of a SES light and a constant engine misfire. In some cases, they may also complain of an engine tick/knock noise. During diagnosis, the technician will find no compression on the misfiring cylinder(s) with 100% leakage into the crankcase.

This may be the result of an aftermarket ECM calibrations/components and detonation that lead to a melted piston.

Recommendation/Instructions:
If SI diagnosis isolates no compression on the misfiring cylinder(s) with 100% leakage into the crankcase, perform the following steps as necessary before disassembling the engine:

•If a lighted bore scope is available, inspect the top of the related piston(s) through the spark plug hole to determine if any of the pistons are melted as shown below. These photos all show examples of pistons that were damaged/melted due to detonation that was induced from aftermarket calibrations and/or components. If this type of piston damage is noted, it is most likely the result of aftermarket ECM calibrations and/or components. Follow the remaining steps to determine if this is a warrantable repair. If this type of piston damage is present and aftermarket items are found during steps 2 or 3, this should not be considered a warrantable repair.
•Inspect for aftermarket components, such as an exhaust, ignition, high performance air filter (K and N style), or air intake system. Take photos and document accordingly if anything is found.
•Determine if factory ECM calibration numbers and CVNs are present by following the latest version of 09-06-04-026.






Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

[VQ35DE]

Crap !

[WickedMom]

Dont worry... it doesnt even apply to our engines...

Just for information, I was trying to get across how serious they are getting. The pictures show a hole in the center of a #2 piston and a melted one as well...

[616 of 933]

wow they really dont want you messing with anything. You would think GM would find a company like ford did with Jack Roush

[DRCUSTOMPARTS]

A tune could cause a piston to melt but not a CAI or an exhaust mod. I'd like to see them prove that my CAI or Borla axlebacks caused this to happen, lol

[Kirk@VectorMotorsports]

I have never heard of a tune causing an engine failure on a N/A engine.

It would only be possible if the knock sensors were disabled and there was at least 8-10 degrees too much timing. The engine would run horrible and sound like a loud diesel truck before failing.

This bulletin actually is stemmed from nitrous use. It is very easy to melt a piston with an non-tuned nitrous system. I have a friend that is a regional service manager and he has been told to look for signs or a nitrous system that has been removed in reference to this bulletin.
They can also take oil samples to test for nitrous.

[WickedMom]

Pretty pictures added.

[sweetair]

I think my Vararam is not going to earn me this result. Interesting read though.

[DRCUSTOMPARTS]

Jess those pics are far from pretty, they're downright ugly to me.

[WickedMom]

There is nothing about a CAI or exhaust causing any issues. They are looking for extreme tunes, and like Kirk said.... nitrous use.

I just posted this to show some of what I see on dealerworld pertaining to tunes.