ERRONEOUS FUEL GAGE READING/ INTERMITTENT ENGINE STALL

SUBJECT: ERRONEOUS FUEL GAGE READING, INTERMITTENT ENGINE STALL, DTC 95 (SERVICE PROCEDURE)

MODELS: 1994-95 CADILLAC DEVILLE WITH 4.9L ENGINE (VIN B - RPO L26)

CONDITION:

SOME OWNERS MAY EXPERIENCE RUNNING OUT OF FUEL AND/OR ENGINE STALL OR MISS WITH DTC 95. THE FUEL GAGE MAY INDICATE 2 TO 6 GALLONS OF FUEL AFTER EXTENDED HIGHWAY DRIVING OF 300 MILES ON A SINGLE TANK OF FUEL, ALTHOUGH THE TANK HAS VERY LITTLE OR OR NO FUEL LEFT.

CAUSE:

IN NORMAL OPERATING CONDITIONS, FUEL TANK VACUUM IS RELIEVED THROUGH THE VAPOR CANISTER VIA A HOSE ATTACHED TO THE FUEL TANK RELIEF VALVE (NOT PART OF THE SENDING UNIT). THIS LINE RUNS FROM THE VENT VALVE TO THE CANISTER. PREVENTING THE SYSTEM TO VENT VACUUM COULD CAUSE THE BOTTOM OF THE FUEL TANK TO FLEX UPWARD AND DURING LOW FUEL CONDITIONS CAUSE THE FLOAT TO CONTACT THE BOTTOM OF THE TANK AND GIVE A FALSE READING. THIS CONDITION WILL EVENTUALLY CAUSE THE VEHICLE TO RUN OUT OF GAS EVEN THOUGH THE FUEL GAGE SHOWS FUEL IN THE TANK. THESE CONDITIONS GENERALLY OCCUR AFTER EXTENDED DRIVING BECAUSE OF THE TIME REQUIRED TO BUILD VACUUM.

CORRECTION:

1. INSPECT THE CANISTER FOR PROPER HOSE CONNECTIONS. PLEASE NOTE THE 1994 DEVILLE 4.9L CANISTER HAS THREE NIPPLE CONNECTIONS. TWO OF THESE NIPPLES ARE "STACKED." THE TOP NIPPLE SHOULD BE CONNECTED TO A RUBBER HOSE WHICH RUNS TO THE THROTTLE BODY. THE BOTTOM NIPPLE SHOULD BE CONNECTED TO AN ALL PLASTIC LINE WHICH RUNS TO THE VENT VALVE ON TOP OF THE FUEL TANK. THE THIRD NIPPLE ATTACHES TO A RUBBER HOSE THAT CONTAINS THE CANISTER VENT WHICH ATTACHES TO THE FAN SHROUD WITH A CLIP (FIGURE 1).

2. VERIFY THAT THE FRESH AIR VENT LINE FROM THE CANISTER TO FAN SHROUD IS NOT KINKED OR RESTRICTED (FIGURE 1).

3. REMOVE THE FRESH AIR VENT AND CAP AND INSPECT THE SLOT OPENING FOR RESTRICTIONS LIKE "FLASHING" FROM THE MANUFACTURING PROCESS. REMOVE ANY DEBRIS FROM THE VENT, CLEAN AND REINSTALL THE VENT CAP AND VENT INTO THE HOSE.

4. IF DEBRIS IS NOT FOUND IN THE VENT, CHECK THE HOSE FROM THE CANISTER TO THE TANK FOR KINKS AND/OR RESTRICTIONS.

WARRANTY INFORMATION:

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: LABOR OPERATION: J6389 LABOR TIME: 0.2 HOUR

FIGURES: 2

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.

COPYRIGHT 1994. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.