FUEL GAUGE READS 1/8 TANK WHEN EMPTY (DIAG. AND REPAIR PROC.)

Subject: FUEL GAUGE READS APPROXIMATELY 1/8 TANK WHEN EMPTY

Model and Year: 1990-92 S/T TRUCKS

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 92-81A-8C, DATED APRIL 1992. AN ADDITIONAL PAGE OF ART HAS BEEN ADDED. ALL COPIES OF 92-81A-6F SHOULD BE DISCARDED.

Some owners of 1990-92 S/T Utilities may experience inaccurate fuel gauge readings. If this condition is encountered, the fuel gauge will read 1/8 of a tank on the gauge when the tank is empty. This is due to the fuel sender float contacting the bottom of the fuel tank. The condition can be corrected by bending the fuel sender's float arm. The float arm must be bent so that the float arm angle is approximately 87 degrees. Figure 1 demonstrates the fuel sender before and after the bending procedure. When correctly bent, the float arm angle will match the template included in this bulletin.

SERVICE PROCEDURE:

Important: Before servicing the fuel sender, proper diagnosis of the fuel gauge must be performed according to "DIAGNOSIS OF THE FUEL GAGE" Section 8C-7 in the 1992 Light Duty Truck Service Manual.

1. Remove the fuel tank as outlined in the "FUEL TANK Replacement" section, in the 1992 Light Duty Service Manual.

2. Remove the fuel sender assembly as outlined in the "FUEL PUMP Removal" section, in the 1992 Light Duty Truck Service Manual.

3. Using the template provided, check the float arm angle (Figures 2 and 3). If the angle does not match the template, grasp the fuel sender with pliers as shown in Figure 4 and bend the float arm until it matches the template (angle equals 87 degrees).

DAMAGE TO THE GAUGE READOUT WILL OCCUR IF THE SENDER IS NOT HELD PROPERLY DURING THE BENDING PROCEDURE.

4. Install the fuel sender assembly as outlined in the "FUEL PUMP Install" section in the 1992 Light Duty Truck Service Manual.

Important: THE FUEL SENDER SEAL RING MUST BE REPLACED (P/N 3893116).

5. Install the fuel tank as outlined in the "FUEL TANK Replacement" section, in the 1992 Light Duty Truck Service Manual.

Important: TIGHTEN THE UPPER TANK STRAPS LAST, TORQUE TO 5.5-8.0 N.m. 4.0-6.0 lbs. ft.)

SERVICE PARTS INFORMATION

Part Number Description Qty. ----------- ----------- --- 3893116 Fuel Sender Seal Ring 1

Parts are currently available from GMSPO.

WARRANTY INFORMATION

For vehicles repaired under warranty use:

Labor Operation: L1225

Use applicable labor time guide for labor hours.

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.