For 1990-2009 cars

# HARD OR NO START AND/OR DOES NOT MAINTAIN FUEL PRESSURE

1984 CUTLASS CIERA & 1985 FIRENZA, CALAIS, CUTLASS CIERA, & NINETY-EIGHT EQUIPPED WITH MPFI ENGINES

Some 1984 and 1985 vehicles equipped with MPFI engines may experience extended engine cranking time, poor driveability, engine will not stay running, and/or vehicle may not maintain fuel rail pressure.

Chart A-7 in Section 6E3 of the Oldsmobile Chassis Service Manual states that while performing the "Fuel System Diagnosis" procedure, if the fuel rail pressure does not hold, but will maintain pressure while pinching the pressure line flex hose, the problem is either a leaking pump coupling hose or a faulty in-tank pump. However, the problem could also be a leaking fuel sender pulsator. See Figure 1.

A simple test to determine which component is causing a pressure line leak-down can be performed in the following manner:

1. Remove the sending unit assembly from tank.

2. With the fuel pick-up sock still attached, submerge the sender assembly in CLEAN water far enough to completely cover the fuel pump and pulsator.

3. Apply regulated air pressure (not to exceed 20 psi) to the pressure line of the sending unit assembly.

4. Watch for air escaping from around the pulsator or the end of the pump to determine which component is leaking.

5. Replace parts as necessary and recheck.

#### NOTICE: Do NOT leave sender submerged in water for extended periods of time; blow dry immediately upon removal.

The new part number for the pulsator is 6472359 and is available through WDDGM.

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.