Fuel - Pump Noise Hesitation, Sag, Loss of Power: Overview

9220pontiac01

Bulletin Number:
92-6-39
Reference Number:
236302
Publish Date:
4/92


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

Models
Affected:
1992 SUNBIRD AND GRAND AM MODELS ALL ENGINES


Condition:

Some vehicles may experience fuel pump noise/whine and/or low fuel pressure, sluggish performance, loss of power or hesitation. Some Sunbird and Grand Am models 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:
SUNBIRD ONLY

Some Sunbird models may have contamination in the fuel tank. This is caused by the die lubricant not being completely rinsed out in the manufacture of the fuel tanks. This will appear as a gel or soap on the modular fuel sender strainer. Vehicles that may exhibit this condition have the VIN breakpoint N7529321 - N7540867

OR

SUNBIRD AND GRAND AM

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 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.