DIESEL WHITE SMOKE/ROUGH RUN COLD START/NEWER CARS

White exhaust smoke and a rough running engine may be experienced on some 1983 vehicles equipped with a V-6 diesel engine. This condition will usually only be noticed on new cars in dealer inventory, or cars that have only been in service a day or two.

The condition may be due to belt drive accessories placing a high load on the engine. With high loads the accelerator must be depressed to maintain engine speed. This causes the timing to be retarded by the action of the advance face cam.

To prevent the retarding of the timing:

In cold weather the engine oil must be a winter grade.

The batteries should be fully charged to prevent a high alternator load.

The idle speed should be set to specification.

The housing pressure cold advance must be working and the advance piston in the injection pump must not be sticking.

Once these cars accumulate some miles, internal engine friction should be reduced and this condition will not occur.

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.