PI: LNF Engine Misfire/Low Compression

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Service Information
2009 Chevrolet Cobalt | Cobalt, G5 (VIN A) Service Manual | Preliminary Information | Document ID: 2482806
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#PI0128A: Engine Misfire/Low Compression - (Jun 1, 2010)


Subject: Engine Misfire/Low Compression


Models: 2008-2010 Chevrolet Cobalt, HHR

2008-2010 Pontiac Solstice

2008-2010 Saturn SKY

2008-2009 Daewoo G2X

2008-2010 Opel GT

Equipped with 2.0L Engine (VIN X - RPO LNF)




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This PI is being revised to remove a bulletin reference. Please discard PI0128.


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Condition/Concern:
Some 2.0L Turbo engines may come in with a misfire on one cylinder.

For further misfire diagnosis, a technician should perform a compression test. The results may lead to a cylinder with low compression (85-90 psi). This may be the cause the misfire. The cylinder with the low compression may have a burned/ damaged piston from detonation. The damage to the piston is usually above and below the first compression ring in an area about 25.4 mm (1 in) in length.

Recommendation/Instructions:
Damage of this type to the piston is usually caused by aftermarket equipment (examples are: air induction systems, intercooler cooling devices, NOS systems, ECM calibrations), all designed to boost the output of the engine. This increased output of the engine can lead to severe detonation in certain conditions. If diagnosed with this condition, the vehicle should be inspected for aftermarket performance equipment and/or calibrations, and it should be noted on the repair order.

The GM Accessories power upgrade kit by itself is designed for this engine and should be the recommended performance enhancing equipment. Using the GM accessory kit with other aftermarket components could damage the engine as well.

If repairs to the engine are the result of the installation or use of a non-GM approved part, the warranty will not be honored.

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.

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