HOT WEATHER DRIVEABILITY 5.7L ENGINE

VEHICLES AFFECTED: 1989 CHEVROLET B-CAR WITH 5.7L, 5.0L, AND 4.3L

Some 1989 5.7L, 5.0L, and 4.3L Throttle Body Injected (TBI) B-cars may exhibit hot weather driveability conditions. They may be in the form of a sag, hesitation, and/or no start and usually occur after an extended idle and/or hot soak. Vehicles exhibiting these conditions may be repaired by installing parts and following the procedure indicated below.

PART: PART NUMBER: ------ ------------- Fuel pump inlet strainer/sock 25121401 Diffuser disc 25027515 O-ring 3893116 Relief valve 17089068

Installation Procedures:

1. Disconnect Battery

2. Remove existing tank pressure control valve underhood and discard.

3. Install new tank pressure control valve (underhood) as shown in illustration # 1.

4. Remove fuel tank pump and sender assembly following applicable shop manual procedure.

5. Remove existing fuel pump strainer/sock and discard.

IMPORTANT: Inspect fuel sender assembly to ensure the installation of either the production spacer or the service correction (consisting of a washer and clamp) on the sender feed pipe that retains the hose coupler in correct location. Reference bulletin #89-6-107.

6. Install diffuser disc over pump inlet, position and install new strainer/sock as shown in illustration # 2, and illustration # 3.

7. Utilizing new sender O-ring, install sender and tank assembly following applicable shop manual procedure.

8. Reconnect the battery.

9. Start vehicle, inspect for fuel leakage and correct as required.

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.