INTAKE FUEL PUMP MAY BECOME LOOSE & CAUSE NOISE- (REPAIR)

INTANK ELECTRIC FUEL PUMP LOOSENS (Revised to Include "Blazers" in Vehicles Affected)

VEHICLES AFFECTED: 1987-88 R/V SUBURBANS AND BLAZERS/JIMMYS EQUIPPED ----------------- WITH TBI GASOLINE ENGINES

Some 1987/88 R/V Suburbans and Blazers/Jimmys equipped with TBI engines and 31 or 40 gallon fuel tanks may experience a condition where the intank electric fuel pump loosens from the sender. This condition may be caused by the fuel pump reservoir (plastic) on the bottom of the fuel tank coming loose and dislodging the fuel pump from the fuel tank sender unit. If this condition is encountered, it can be repaired using the following procedure.

1. Drain and remove the fuel tank. Use procedures on page 4-35, of the 1988 Fuel and Driveability Manual, X8836.

2. Remove fuel tank sender. The sender must also be inspected for damage. If the sender is damaged, it must be replaced.

3. Looking thru fuel tank sender opening, locate fuel tank reservoir (yellow plastic) on bottom of tank. Check attachment of reservoir to tank - reservoir is held to the bottom of tan by two (2) welded studs and two (2) attaching retainers. Reservoir must be tight against bottom of tank. Three (3) different loose reservoir conditions may exist with the reservoir.

A. The reservoir is loose on the welded studs, and the retainers have moved up the welded studs. B. One (1) of the retainers has come off the stud and the reservoir has rotated around the other stud. C. Both of the retainers have come off the welded studs and the reservoir is moving around inside the fuel tank.

To repair conditions A, B, or C use the following steps:

NOTICE: When inspecting the retainers, all retainers that are damaged (cracked or broken) must be replaced. Reusing damaged retainers could cause a repeat incident.

Condition A - Working thru the fuel tank sender opening, push the original retainers, if not damaged, down on the studs as far as possible. Using an extension, a socket swivel and a deep 7/16 socket, install one (1) flange nut, P/N 274796, on each stud. Screw nuts down on studs and torque nuts to 1.8-2.2 Nm (16-20 in/lbs).

Condition B - Working thru fuel tank sender opening, rotate reservoir back into position on both welded studs. Push the one (1) remaining retainer, if not damaged, down as far as it will go. Install one (1) washer P/N 331544 on stud with missing retainer. Install one (1) flange nut P/N 274796 on each stud. Screw nuts down and torque nuts to 1.8-2.2 Nm (16-20 in/lbs).

Condition C - Working thru fuel tank sender opening, reinstall reservoir on weld studs. The fuel drainage opening in the reservoir must face the rear of the tank. Install one (1) washer, P/N 331544, on each stud. Install one (1) flange nut, P/N 274796 on each stud. Screw nuts down and torque nuts to 1.8-2.2 Nm (16-20 in/lbs).

Do not install any flange nuts without either an undamaged original retainer or a washer between the reservoir and the nut as the nut could cut into the reservoir and cause a repeat failure. The flange nut and washer MUST NOT be substituted with uncoated parts. The parts listed are coated to prevent corrosion inside the fuel tank.

4. Reinstall the sender and fuel pump.

5. Reinstall the fuel tank.

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.