DIESEL CALIF. ENGINE TIMING REQUIRED AFTER PUMP REMOVAL

MODELS: 1982-83 "C-K" WITH YF5 CALIFORNIA EMISSIONS LIGHT DUTY 6.2L DIESEL

Any service on the 6.2L light duty diesel engine (built to Califomia specifications) which necessitates removal or replacement of the injection pump, requires a different static timing procedure.

Light duty engines built to California specifications have been timed with a microwave process. After timing with the microwave, an additional mark "O" is stamped over the pump flange/housing interface.

When viewing the California timed engine, the two (2) timing marks (as on Federal engines) will be visible. These may or may not be lined up. In addition, an "O" will be visible, stamped on the flange interface. The "O" should be round. Any deviation of the timing will result in two (2) half circles not matching.

If a pump is removed for service and is replaced on the same engine, be sure to match the "O" for correct timing setting.

If a new pump or a pump that was not previously on the engine is installed, do not use any "O" marks. Instead, use the normal timing marks and align according to the information which is detailed in Service Bulletin 83-B-25.

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.