FUEL PUMP RELATED DRIVABILITY ISSUES-DIAGNOSTIC INFORMATION

SUBJECT: FUEL PUMP RELATED DRIVEABILITY ISSUES (DIAGNOSTIC INFORMATION)

MODELS AFFECTED: 1991-92 SKYLARKS, CENTURYS, REGALS AND RIVIERAS

CONDITION:

--------- Some vehicles may experience fuel pump noise/whine and/or low fuel pressure, sluggish performance, loss of power or hesitation or service engine soon light with codes 32 or 44. Some cars may experience the condition most evident during the first five minutes of operation or under heavy acceleration.

CAUSE:

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

IMPORTANT: --------- On all Skylarks with modular senders, ALWAYS replace the pulse dampener seal supplied in the fuel pump kit. Failure to replace the pulse dampener seal may result in repeated low fuel pressure situations.

CORRECTION:

---------- Use Section 6E3 of the appropriate service manual to diagnose possible fuel system related problems. The vehicle may need to be operated under a load while monitoring fuel pressure to detect the problem. Make certain the fuel system is performing to specifications before other engine control system components are serviced.

PROCEDURE:

--------- Follow procedures identified in the appropriate service manual. For 1992 Skylark models specifically, see Bulletin 92-6E-17 issued May, 1992. For electrical intermittences, see Section 8A of the appropriate service manual. Also see instruction on use of required tool J38125.

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.