FUEL PUMP NOISE,HESITATES,LOSS OF POWER -PUMP OR CONTAM. FUEL

SUBJECT: FUEL PUMP NOISE, ENGINE HESITATION, SAG, LOSS OF POWER OR NO START (FUEL PUMP)

MODELS AFFECTED: 1992 SKYLARK

CONDITION:

Some vehicles may experience fuel pump noise/whine and/or low fuel pressure, sluggish performance, loss of power or hesitation. Some Skylarks may experience the condition most evident during the first five minutes of operation or under heavy acceleration. The condition may be intermittent and temporarily eased when the accelerator pedal is temporarily released and then reapplied.

CAUSE:

----- The fuel pump may contain a tight bearing that causes internal binding in the pump.

CORRECTION:

---------- Follow appropriate service manual procedures when diagnosing fuel related problems. When the symptoms are present the condition may sometimes be verified by:

A. A drop in fuel pressure of 69 kPa (10 psi.) or more when testing fuel pressure as outlined in the service manual.

B. A lean oxygen sensor reading using the Tech 1 scanner.

Important: If no other cause for fuel starvation is found, replace the fuel pump.

Procedure:

---------

1. Remove modular fuel sender as outlined in the Skylark service manual, Section 6C, "Modular Fuel Sender Replacement."

2. Remove external fuel strainer.

3. Remove CPA#8 (connector position assurance) from electrical connector and disconnect fuel pump electrical connector.

4. Gently release tabs on sides of fuel sender to cover assembly. Begin by squeezing the sides of the reservoir and releasing the tab opposite the fuel level sensor. Move clockwise to release the second and third tab in the same manner. (Figure 2)

5. Lift cover assembly out far enough to disconnect the fuel pump electrical connection.

6. Carefully pry snap ring out of groove on fuel pump outlet. (View B)

7. Rotate fuel pump baffle #18 counterclockwise and remove baffle pump assembly from retainer #7.

8. Replace the fuel pump seal/dampener. (Figure 4)

9. Install fuel pump outlet retainer #21 on fuel pump outlet #20. Index the snap ring so that the ends are positioned in the groove #22 facing the fuel pump electrical connection. (View A and B)

10. Install new fuel pump and baffle assembly onto reservoir retainer #7 and rotate clockwise until seated.

11. Place fuel pump outlet #20 over retainer #7 so that snap ring ends #21 face fuel pump electrical connection and press firmly into place making certain the snap ring is seated and over each tab on outlet. (View B)

Important: Gently pull on fuel pump outlet to assure a secure fastening. If not secure, replace fuel sender. Failure to fully seat retainer snap ring may cause aeration and poor performance.

12. Lower retainer assembly #7 partially into reservoir. Line up all three sleeve tabs.

Important: Gently pull on fuel pump reservoir from retainer to assure a secure fastening. If not secure replace entire fuel sender.

13. Install fuel pump connector and CPA#8 (connector position assurance) to fuel sender cover #7.

14. Install new external fuel strainer #14.

15. Reinstall fuel tank in vehicle as outlined in "Modular Fuel Sender Replacement" in the Skylark service manual.

Parts Information

Fuel Filter P/N 25121293 Fuel Pump Kit P/N 25028921

Parts are currently available from GMSPO.

WARRANTY INFORMATION:

Labor Operation No.: T1849 Labor Time: 1.4 hrs.

1 HARNESS ASSEMBLY (ABOVE COVER) - FUEL PUMP AND FUEL SENDER WIRING

2 CONNECTOR ASSEMBLY - FUEL SENDER WIRING

3 FUEL PIPES (3)

4 COVER ASSEMBLY - FUEL SENDER

5 PIPE (CONVOLUTED) - FUEL SENDER OUTLET

6 SUPPORT ASSEMBLY (THEE HOLLOW SUPPORT OR GUIDE PIPES) - FUEL PUMP RESERVOIR

7 RETAINER - FUEL PUMP RESERVOIR

8 CONNECTOR POSITION ASSURANCE (CPA)

9 HARNESS ASSEMBLY (BELOW COVER) - FUEL PUMP

10 HARNESS ASSEMBLY (BELOW COVER) FUEL LEVEL SENDER

11 RESERVOIR - FUEL PUMP FUEL

12 SENSOR ASSEMBLY - FUEL LEVEL

13 PUMP ASSEMBLY (JET PUMP ASSEMBLY) - FUEL PUMP RESERVOIR

14 STRAINER (EXTERNAL) - FUEL SENDER

15 PAD (BUMPER) - FUEL SENDER

16 VALVE (SECONDARY UMBRELLA VALVE) - FUEL PUMP RESERVOIR INLET CHECK

17 STRAINER - FUEL PUMP FUEL

18 BAFFLE (ISOLATOR CUP) - FUEL PUMP

19 PUMP ASSEMBLY (ROLLERVANE) - FUEL

20 OUTLET - FUEL PUMP

21 SNAP RING - FUEL PUMP OUTLET

22 PIPE - JET PUMP

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.