For 1990-2009 cars

# DRIVEABILITY SYMPTOMS DUE TO FUEL INJECTOR DEPOSITS

REVISION: 11/13/97

THIS BULLETIN IS BEING REVISED TO UPDATE CORRECTION INFORMATION. ______________________________________________________________________ REVISION: 02/03/98

THIS BULLETIN IS BEING REVISED TO UPDATE WARRANTY INFORMATION. PLEASE DISCARD CORPORATE SERVICE BULLETIN NUMBER 77-63-04 (SECTION 6E--ENGINE FUEL AND EMISSION). ______________________________________________________________________

#### SUBJECT: DRIVEABILITY SYMPTOMS DUE TO FUEL INJECTOR DEPOSITS (CLEAN INJECTORS)

#### MODELS:

1994-96 BUICK REGAL 1994-98 BUICK CENTURY, SKYLARK 1994-96 CHEVROLET CORSICA, BERETTA 1995-97 CHEVROLET MONTE CARLO, LUMINA 1996 CHEVROLET LUMINA APV 1997-98 CHEVROLET MALIBU, VENTURE 1994-96 OLDSMOBILE CUTLASS CIERA 1994-97 OLDSMOBILE CUTLASS SUPREME, ACHIEVA 1997-98 OLDSMOBILE CUTLASS 1996-98 OLDSMOBILE SILHOUETTE 1994-98 PONTIAC GRAND AM, GRAND PRIX 1996-98 PONTIAC TRANS SPORT WITH 3100, 3400 V6 ENGINES (VINS E, M - RPOS LA1, L82)

#### CONDITION:

SOME OWNERS MAY EXPERIENCE A DRIVEABILITY SYMPTOM OF LONG OR HARD STARTS, CHUGGLE, ROUGH IDLE AND LIGHT OR INTERMITTENT MISFIRE. THE MALFUNCTION INDICATOR LIGHT (MIL) MAY ALSO ILLUMINATE.

#### CAUSE:

DUE TO VARIOUS FACTORS, THE INJECTOR MAY BECOME RESTRICTED. AT THIS POINT, NO SPECIFIC FUEL OR FUEL CONSTITUENT, OR ENGINE CONDITION, OR A COMBINATION OF FACTORS HAS BEEN IDENTIFIED AS CAUSING THE RESTRICTION. THE RESTRICTION CAUSES THE ENGINE TO OPERATE AT A LEAN AIR FUEL RATIO. THIS MAY THEN EITHER TRIGGER THE MIL LIGHT TO ILLUMINATE OR THE ENGINE TO DEVELOP VARIOUS DRIVEABILITY SYMPTOMS.

#### CORRECTION:

THESE DEPOSITS CAN BE CLEANED ON THE VEHICLE USING THE FOLLOWING PROCEDURE. UNDER NO CONDITION SHOULD THIS PROCEDURE BE MODIFIED, CHANGED OR SHORTENED.

#### NOTICE: USE ONLY THE FOLLOWING PROCEDURE AND CHEMICALS. USING OTHER PRODUCTS, SUCH AS AEROSOLS, ARE NOT EFFECTIVE AND MAY DAMAGE FUEL SYSTEM COMPONENTS.

THE FOLLOWING KENT-MOORE TOOLS OR EQUIVALENT ARE REQUIRED.

TOOL NUMBER DESCRIPTION J39021 FUEL INJECTOR COIL/BALANCE TESTER

J39021-210 FUEL INJECTOR SELECTOR ADAPTER BOX

J39021-306 FUEL INJECTOR TEST HARNESS

J35800/J35800-A FUEL INJECTOR CLEANER

1) DISCONNECT THE 10 PIN FUEL RAIL ELECTRICAL CONNECTOR. REFER TO THE APPROPRIATE VEHICLE SERVICE MANUAL SECTION FOR CONNECTOR LOCATION.

2) CONNECT KENT-MOORE TOOL J39021, FUEL INJECTOR COIL/BALANCE TESTER, TO THE KENT-MOORE J39021-210 FUEL INJECTOR SELECTOR ADAPTER BOX. CONNECT KENT-MOORE J39021-306 FUEL INJECTOR TEST HARNESS TO THE ENGINE'S INJECTOR FUEL RAIL ELECTRICAL CONNECTOR. THIS ALLOWS YOU TO TEST THE FUEL INJECTORS WITHOUT REMOVING THE UPPER INTAKE PLENUM.

3) USING THE INJECTOR TESTER J39021, PERFORM AN INJECTOR BALANCE TEST ON EACH INJECTOR. RECORD THE FUEL PRESSURE DROP ON EACH INJECTOR. THIS CAN BE DONE BY UTILIZING THE FUEL INJECTOR (KENT-MOORE J39021- 210) SELECTOR ADAPTER BOX TO SELECT THE INDIVIDUAL FUEL INJECTORS.

4) SUBTRACT THE LOWEST PRESSURE DROP (LEANEST INJECTOR) FROM THE HIGHEST PRESSURE DROP (RICHEST INJECTOR). IF THERE IS MORE THAN A 20 KPA (3 PSI) DIFFERENCE BETWEEN THE RICHEST AND LEANEST INJECTOR, THEN THE INJECTORS MAY BE THE CAUSE OF THE DRIVEABILITY PROBLEM. SEE THE TABLE BELOW TO DETERMINE IF CLEANING IS APPROPRIATE.

EXAMPLE ONE

CYLINDER NUMBER CYL-1 CYL-2 CYL-3 CYL-4 CYL-5 CYL-6 PRESSURE DROPS 43KPA 68KPA 42KPA 41KPA 44KPA 42KPA (6PSI) (10PSI) (6PSI) (6PSI) (6PSI) (6PSI) MAX DIFFERENCE: 68-41 = 27 KPA / 10-6 = 4 PSI ALTHOUGH THE PRESSURE DROP IS GREATER THAN 20 KPA (3 PSI), CYLINDER 2 STANDS OUT AS BEING RICH COMPARED TO THE OTHER CYLINDERS. DO NOT CLEAN. REPLACE INJECTOR NUMBER 2. CHARGE TIME TO J5650.

EXAMPLE TWO

CYLINDER NUMBER CYL-1 CYL-2 CYL-3 CYL-4 CYL-5 CYL-6 PRESSURE DROPS 23KPA 48KPA 24KPA 43KPA 44KPA 46KPA (3PSI) (7PSI) (3PSI) (6PSI) (6PSI) (7PSI) MAX DIFFERENCE: 48-23 = 25 KPA / 7 - 3 = 4 PSI THE PRESSURE DROP IS GREATER THAN 20 KPA (3 PSI), CYLINDERS 1 AND 3 APPEAR TO BE LEAN. CLEAN AND RE-TEST. IF CLEANING DID NOT RESTORE FLOW, REPLACE THE DEFECTIVE INJECTOR(S). CHARGE TIME TO J5650.

5) IF THERE IS LESS THAN A 20 KPA (3.0 PSI) DIFFERENCE BETWEEN THE HIGHEST AND LOWEST FUEL PRESSURE DROP, THE FUEL INJECTORS ARE OPERATING PROPERLY AND FURTHER DIAGNOSTICS ON THE VEHICLE SYSTEMS SHOULD BE PERFORMED.

6) REMOVE THE J39201-306 HARNESS ADAPTER AND RECONNECT THE FUEL RAIL 10 PIN ELECTRICAL CONNECTOR.

7) FILL THE FUEL INJECTOR CLEANER TANK, KENT-MOORE TOOL J35800 OR EQUIVALENT, WITH A 5% SOLUTION (50ML, 1.6 FLUID OUNCES) OF GM 1050002 (CANADIAN P/N 992872) OR GM 12345088 TOP ENGINE CLEANER TO 1 LITER (1.057 QT.) OF UNLEADED PETROL/GASOLINE. BE SURE TO FOLLOW THE INSTRUCTIONS SUPPLIED WITH THE TOOL.

#### NOTICE: GM TOP ENGINE CLEANER IS THE ONLY CHEMICAL RECOMMENDED. DO NOT USE OTHER CHEMICALS, THEY MAY CONTAIN METHANOL WHICH CAN DAMAGE FUEL SYSTEM COMPONENTS.

#### NOTICE: UNDER NO CONDITION SHOULD THE FUEL CLEANING SOLUTION BE EMPTIED INTO THE VEHICLE'S FUEL TANK. THE SOLUTION MAY DAMAGE THE FUEL PUMP AND OTHER FUEL SYSTEM COMPONENTS.

#### NOTICE: DO NOT EXCEED A 5% CLEANING SOLUTION CONCENTRATION. HIGHER CONCENTRATIONS MAY DAMAGE FUEL SYSTEM COMPONENTS.

8) ELECTRICALLY DISABLE THE VEHICLE'S FUEL PUMP BY REMOVING THE FUEL PUMP RELAY AND DISCONNECTING THE OIL PRESSURE SWITCH CONNECTOR.

9) CONNECT THE J35800 TO THE VEHICLE'S FUEL RAIL.

10) PRESSURIZE THE J35800 TO 170 KPA (25 PSI).

#### NOTICE: DO NOT EXCEED 170 KPA (25 PSI). EXCEEDING THIS PRESSURE WILL ALLOW CLEANING SOLUTION TO FLOW PAST THE FUEL PRESSURE REGULATOR INTO THE TANK WHICH MAY DAMAGE THE FUEL PUMP.

11) REMOVE THE VACUUM LINE FROM THE FUEL PRESSURE REGULATOR AND PLUG THE VACUUM HOSE.

12) START THE VEHICLE AND RUN APPROXIMATELY 15 MINUTES.

13) DISCONNECT J35800 FROM THE VEHICLE.

14) RECONNECT THE FUEL PUMP RELAY AND OIL PRESSURE SENSOR CONNECTOR. REINSTALL THE FUEL PRESSURE REGULATOR VACUUM HOSE.

15) REPEAT STEPS 1-4 (INJECTOR BALANCE TEST) AND RECORD THE FUEL PRESSURE DROP FOR EACH CYLINDER.

16) SUBTRACT THE LOWEST FUEL PRESSURE DROP FROM THE HIGHEST FUEL PRESSURE DROP. IF THE VALUE IS 15 KPA (2 PSI) OR LESS, NO ADDITIONAL ACTION IS REQUIRED. IF THE VALUE IS GREATER THAN 15 KPA (2 PSI), REPLACE THE INJECTOR WITH THE LOWEST FUEL PRESSURE DROP. BE SURE TO FOLLOW THE REPAIR PROCEDURE FOR INJECTOR REPLACEMENT AS OUTLINED IN SECTION 6E3 OF THE SERVICE MANUAL.

17) ROAD TEST THE VEHICLE TO CONFIRM THAT THE CUSTOMER CONCERN IS CORRECTED.

#### WARRANTY INFORMATION:

#### NOTICE: J5645 CANNOT BE USED IN CONJUNCTION WITH ANY INJECTOR REPLACEMENT LABOR CODE. IF INJECTOR CLEANING FAILS TO RESTORE DRIVEABILITY OR MISFIRE COUNTS AND INJECTOR REPLACEMENT BECOMES NECESSARY, YOU MUST CHARGE YOUR WORK TO J5650 (INJECTOR FUEL REPLACE).

FOR VEHICLES REPAIRED UNDER WARRANTY, USE: OTHER LABOR LABOR LABOR OPERATION DESCRIPTION TIME ADD HOURS CARLINE

J5645 INJECTOR, FUEL 0.9 HR. 0.7 HR. FOR 0.0 HR. A/L/N/W - DIAGNOSIS CLEANING

J5645 INJECTOR, FUEL 1.0 HR. 0.7 HR. FOR 0.0 HR. U-VAN - DIAGNOSIS CLEANING J5650 INJECTOR, FUEL USE A.0.4 HR. 0.9 HR. A/L/N/W - REPLACE PUBLISHED PERFORM LABOR INJECTOR OPERATION BALANCE TEST TIME. B.IF APPLICABLE C.IF APPLICABLE D.0.3 HR. DIAGNOSIS TIME

FIGURES: 00 ATTACHMENTS: 00

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.

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