GM Service Manual Online
For 1990-2009 cars only

POOR DIESEL ENGINE PERFORMANCE INJECTION PUMP CAM PIN REPLACE

WHEN PERFORMING GOVERNOR WEIGHT RETAINER RING REPAIRS ON 1980, 1981 AND 1982 MODEL DIESEL INJECTION PUMPS, MAKE SURE THAT THE CAM ADVANCE PIN IS INSERTED INTO THE SMALLEST HOLE IN THE CAM RING. FAILURE TO DO SO WILL RESULT IN EXCESSIVE WEAR OF THE BALL ON THE CAM ADVANCE PIN, CAUSING POOR PERFORMANCE, SMOKE AND POOR FUEL ECONOMY. TO DETERMINE WHICH HOLE IS THE SMALLEST, USE A HEAD LOCKING SCREW. THE SCREW WILL ENTER THE LARGE HOLES BUT NOT THE SMALL ONE.

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.