IN TANK FUEL PUMP COUPLER DISCONNECT/REASSEMBLE

MODELS: ALL 1989 LIGHT DUTY TRUCKS WITH THROTTLE BODY FUEL INJECTION

Some 1989 trucks equipped with throttle body injection (TBI) engines (see list below) may experience a condition where fuel delivery to the engine is interrupted. This condition may be the result of the in tank fuel pump becoming uncoupled from the fuel tank sender assembly.

Engine Displacement VIN and RPO Identification ------- -------------- 2.5L TBI (LN8) E 2.8L TBI (LL2) R 4.3L TBI (LB4) Z 5.0L TBI (L03) H 5.7L TBI (L05) K 7.4L TBI (L19) N

Vehicles that are diagnosed as exhibiting this condition may be repaired by recoupling the pump to the sender, utilizing an additional damp and washer in conjunction with existing parts and following service procedure below.

Service Procedure:

1. Following applicable shop manual procedures, remove fuel tank sender unit.

2. Loosen both coupler clamps and remove coupler from sender (See Illustration).

3. With a clean dry cloth, wipe off fuel pump outlet tube, sender pressure pipe and coupler hose I.D. (See Illustration).

4. Position plastic clamps on coupler and install coupler on fuel pump outlet pipe.

NOTICE: DO NOT LUBRICATE COUPLER TO FACILITATE ASSEMBLY.

5. Slide clamp, P/N 25518880 and washer, P/N 3824159 on sender pressure pipe insuring orientation of clamp is as shown in Illustration.

6. Bend rubber coupler slightly and install on sender pressure pipe.

7. Properly position both plastic clamps and tighten.

8. Slide washer and clamp down sender pressure pipe to a position against the rubber coupler.

9. With washer and damp properly positioned and tight against coupler, tighten clamp.

NOTICE: INSURE CLAMP IS PROPERLY POSITIONED AS SHOWN IN ILLUSTRATION TO ELIMINATE POSSIBLE WIRE CHAFING.

10. Utilizing new O-ring, P/N 3893116 install fuel tank sender unit into fuel tank.

11. Following applicable shop manual procedure, reinstall fuel tank.

12. Start vehicle, inspect for any fuel leaks and correct if required.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use:

Labor Operation Number: J5590

Refer to the 1989 Light Duty Labor Time Guide for the appropriate time allowance.

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.