LOSS OF POWER, HARD, START, ERRATIC OPERATION-DIESEL

MODELS: 1982-1985 C, K, G, P WITH 6.2L DIESEL ENGINES

Some vehicles equipped with the 6.2L diesel engine may experience conditions such as loss of power, hard starting, erratic engine operation, and excessive black or white smoke. Refer to Truck Service Bulletin 84-B-74 for fuel system diagnostics. If on-vehicle diagnosis indicates that the injection pump is the problem, a worn or binding injection pump advance piston may be the cause. A new nickel-plated advance piston has been introduced on the 1986 6.2L diesel engine. This nickel-plated advance piston reduces piston/bore wear and piston seizure. This piston has been made available through Stanadyne Diesel Systems dealers as a service part for 1982 through 1985 6.2L diesel fuel injection pumps. Installation of the nickel-plated advance piston must be requested by the GMC dealer when the pump is sent to the Stanadyne dealer for repair. Stanadyne Part Numbers:

Description P/N ----------- --- Nickel-plated Advance Piston (Standard Bore) 27865

Nickel-plated Advance Piston (.008" Oversize) 27869

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.