FUEL PUMP NOISE AFTER VIN BREAKPOINT- P/N & REPAIR

FUEL PUMP NOISE

VEHICLES AFFECTED: 1988 "W" CAR ----------------- Some 1988 "W" cars, assembled prior to the VIN breakpoints indicated below, may exhibit an increased level of fuel pump noise audible in the vehicle passenger compartment.

Buick J1421781

Pontiac JF202360

Oldsmobile JD300211

This condition may be addressed by installing a new fuel pump with contained check valve feature and new tank to underbody insulator pads that have been released as a interim production change. Service procedure and parts available from GM Parts are indicated below.

Service Procedure

1. Drain and lower fuel tank following applicable shop manual procedures.

2. Remove fuel tank sender and pump assembly.

3. Remove existing anti-squeak material from tank and discard. Clean top of tank.

4. Position and secure eight (8) insulator pads, P/N 10114724, to the top of fuel tank as shown in Figure 1.

5. Remove fuel pump from sender assembly and discard.

6. Inspect pulsator to insure it is of the latest design with "dual hump" cover (See Figure 2) . If not of the "dual hump" configuration, discard and replace with P/N 25094266.

7. Reassemble sender/pump assembly utilizing new fuel pump contained in fuel pump kit, P/N 25116156.

8. Install sender/pump assembly into fuel tank utilizing new fuel sender O-ring contained in fuel pump kit.

9. Inspect tank assembly to insure fuel and vapor pipes are properly positioned and retained in fuel line separators/spacers. When properly installed separators/spacers should contact tank top, while clearance is maintained between pipes and tank.

10. Raise and position fuel tank to vehicle underbody and secure in position torquing strap bolts to 25 ft. lbs.

11. Inspect and correct any obvious tank or sender pipe(s) contact with vehicle underbody.

12. Reconnect fuel/vapor hoses and electrical connector.

13. Start vehicle, inspect for any fuel leakage and repair as required.

Part Number Description ----------- ----------- 25116156 Fuel Pump Kit

10114724 Insulator Pad Unit (8pcs./unit)

* 25094266 Pulsator

* Only required when existing pulsator is of old style (reference step 6).

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.