INCORRECT FUEL GAUGE READING REDESIGNED FUEL SENDER. GMC Truck GMC MD Conventional 97.5" 1988

********************************************************************* THIS BULLETIN CANCELS AND REPLACES GMC TUCK SERVICE BULLETIN # 89-T-2 DATED MARCH, 1989 , CORPORATE NUMBER 866318 TO CORRECT THE FUEL SENDE PART NUMBER. ALL COPIES OF 89-T-24 SHOULD BE DESTROYED *********************************************************************

SOME 1988 AND 1989 MEDIUM DUTY VEHICLES EQUIPPED WITH ELECTRIC FUEL PUMPS MOUNTED INSIDE THE 50 GALLON FUEL TANK, MAY EXPERIENCE INCORREC FUEL GAUGE READING. THIS CONDITION MAY BE THE RESULT OF THE SENDER FLOATING ARM INTERFERING WITH THE FUEL TANK BAFFLE. IF THIS CONDITION EXISTS, THE FUEL GAUGE WILL READ A MAXIMUM OF 3/4 - 7/8 FULL.

LISTED BELOW ARE TWO POSSIBLE CONDITIONS WHERE FUEL SENDER MAY INTERFERE WITH FUEL TANK BAFFLE:

1. VEHICLES MANUFACTURED BETWEEN JUNE 6, 1988 AND AUGUST 8, 1988 (VEHICLE IDENTIFICATION NUMBERS LISTED BELOW). EFFECTIVE WITH VEHICLES MANUFACTURED AFTER AUGUST 8, 1988, THE FUEL TANK BAFFLE WAS NOTCHED TO ELIMINATE INTERFERENCE.

VIN BREAKPOINTS _______________

JUNE 6, 1988 GMC 1GDL7D1B5JV530108 CHEVROLET 1GDL7D1B5JV116299

AUGUST 8, 1988 GMC 1GDM7D1Y0KV500072 CHEVROLET 1GBM7D1YXKV100030

2. DEALER INSTALLED ELECTRIC FUEL PUMP (PART OF IN TANK FUEL PUMP KIT, P/N 622083 GMC TRUCK SERVICE BULLETIN 88-T-120) IN 50 GALLON FUEL TANKS. IF THIS CONDITION IS ENCOUNTERED, IT CAN BE REPAIRED BY INSTALLING TH REDESIGNED FUEL TANK SENDER, LISTED LATER IN THIS BULLETIN.

LISTED BELOW ARE THE REMOVAL AND INSTALLATION INSTRUCTIONS FOR THE FUEL TANK SENDER:

SERVICE PROCEDURE - REMOVAL/INSTALLATION ________________________________________

1. DISCONNECT NEGATIVE BATTERY CABLE.

2. DRAIN FUEL TANK. REFER TO THE MEDIUM DUTY SERVICE MANUAL 6C FOR INSTRUCTIONS AND PRECAUTIONS.

IMPORTANT: USE CAUTION WHEN DRAINING FUEL TANK.

3. INSTALL A JACK UNDER THE FUEL TANK FOR SUPPORT. REMOVE AND RETAIN THE NUTS FROM THE TANK SUPPORT STRAP STUD BOLTS.

4. DISCONNECT THE WIRING HARNESS AT THE FUEL TANK SENDING UNIT.

5. SLIDE THE FUEL TANK OUT BOARD OF VEHICLE AND DISCONNECT THE FUEL LINES FROM THE FUEL SENDER.

6. REMOVE AND DISCARD THE FUEL TANK SENDING UNIT AND GASKET. SAVE FASTENERS.

7. REMOVE ELECTRIC FUEL PUMP FROM SENDER AND INSTALL ON NEW SENDER

8. INSTALL NEW GASKET AND FUEL SENDER/PUMP ASSEMBLY.

9. RECONNECT THE FUEL LINES TO THE SENDER/PUMP ASSEMBLY.

10. REPOSITION FUEL TANK.

11. REINSTALL THE NUTS ON THE FUEL TANK SUPPORT STRAP STUD BOLTS AN TORQUE 45 NM (33 FT. LBS.).

12. REFILL FUEL TANK.

13. RECONNECT NEGATIVE BATTERY CABLE.

PARTS INFORMATION _________________

PART NUMBER DESCRIPTION QUANTITY ___________ ___________ ________

25027609 SENDER ASSEMBLY 1 PER TANK

PARTS ARE EXPECTED TO BE AVAILABLE ON AUGUST 28, 1989. UNTIL THEN, NORMAL PART ORDERS WILL NOT BE ACCEPTED BY GMSPO. ONLY VERIFIABLE EMERGENCY VIP ORDERS WILL BE ACCEPTED. SPO WILL MAKE EVERY EFFORT TO OBTAIN PARTS. ALL PARTS WILL BE PLACED ON 400 CONTROL TO WAIVE VIP SURCHARGES. HOWEVER, THE PART WILL BE SHIPPED PREMIUM TRANSPORATION AT DEALER'S EXPENSE. ALL OTHER ORDER TYPES WILL BE CANCELED AS INCORRECTLY ORDERED WHILE THE 400 CONTROL IS IN PLACE.

FOR REPAIRS TO VEHICLES UNDER WARRANTY USE:

LABOR OP: L1224 RIGHT FUEL TANK LABOR TIME: .6 HRS. LABOR OP: L1225 LEFT FUEL TANK LABOR TIME: .6 HRS.

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.