'TICS' FUEL INJECTION PUMP/ECM EXCHANGE PROGRAM INFORMATION

SUBJECT: TICS FUEL INJECTION PUMP AND ECM EXCHANGE PROGRAM (INFORMATIONAL)

MODELS: 1992 W5, W6, AND W7

This bulletin affects all 1992 W5, W6, W7, W7HV, AND W7T trucks equipped with the TICS System (Timing and Rate Control System).

The fuel injection pump used on these engines cannot be repaired by an authorized Zexel repair station. Therefore, when warranty repairs are required, the following steps or procedures must be followed:

SERVICE PROCEDURE:

Repair of the fuel injection pump assembly.

1. Fill out the TICS Check Sheet and perform the necessary checks and inspections in determining if a fuel injection pump assembly R&R is necessary. The TICS form number is IST-SVC-5126. Additional forms are available at no cost through Retail Publications. 2. Once it has been determined that the fuel pump assembly must be removed and replaced, please contact GMC Truck Technical Assistance Center (TAC) immediately. Please have the Diagnostic Sheet available for reference. 3. Once approved for exchange, a fuel injection pump assembly will be shipped to your location, on a priority basis, from Zexel. 4. Upon receiving the pump, remove the pump assembly and, inside the box, you will find two plastic bottles with instructions. 5. Take fuel and oil samples as directed. 6. Contact GMC Truck Technical Assistance Center (TAC) for return instructions.

Note: Arrangements for return of the pump must be made by the next business day.

For replacement of the ECM only:

1. Use the TICS form, which is the same as the fuel pump injection exchange program. 2. Upon determining that an ECM unit must be replaced, contact GMC Truck Technical Assistance Center (TAC). 3. Upon approval for ECM replacement, TAC will place an order to AIPDN and an ECM will be shipped to your dealership. 4. Return the failed ECM unit to the following location FREIGHT PREPAID: Isuzu Truck of America, inc. 1180 Durfee Avenue, Suite 100 South El Monte, CA 91733 Attn: Product Reliability Department

NOTE: Please include the TICS form with the ECM. Ship part freight prepaid.

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.