DIESEL ENGINE TIMING ALTERNATE TIMING PROCEDURE

MODELS AFFECTED: All Diesels

The Service Manual points out that the timing marks on the Injection Pump and the Injection Pump Adaptor should be close to being lined up after dynamic timing. If they are not, and the engine still exhibits a poor performance condition, the dynamic timing still could be incorrect. It is possible that a misfiring cylinder will result in the incorrect timing. Whenever this occurs, it is essential that timing be checked in the alternate cylinder. Timing can be checked in cylinders 2 and 3 on a V-8, and cylinders 1 and 4 on a V-6. If a difference in timing exists between cylinders, try timing the engine in both positions to determine which timing gives the best engine performance.

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.