INABILITY TO SET IGNITION TIMING

1987 SUNBIRD MODELS EQUIPPED WITH LT2/LT3 2.OL OHC ENGINE (VIN CODE K AND M)

Early build LT2 and LT3 engines used a crankshaft dampner that could experience an outer "Timing" ring rotation relative to the inner crankshaft drive. The result is the inability to check or set spark timing after miles of customer service.

A new crackshaft dampner pulley, P/N 10083143, repairs the original outer ring slippage. Below are the VIN Codes of potentially affected vehicles.

ENGINE VIN'S VIN CODE PRIOR TO

K H7566886

M H7567626

Use applicable Labor Operation and Time.

SERVICE DEPARTMENT PONTIAC DIVISION GENERAL MOTORS CORPORATION

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those 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 a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.