SMU - SECTIONS 3 & 6E3 DRIVEABILITY & EMISSIONS. GMC Truck Safari

SUBJECT: SERVICE MANUAL UPDATE-SECTIONS 3 AND 6E3-DRIVEABILITY AND EMISSIONS-REVISED CHART A-7 POPPET NOZZLE DIAGNOSIS, UNDER CIRCUIT DESCRIPTION

MODELS: 1992-95 CHEVROLET AND GMC TRUCK S/T, M/L MODELS 1992-94 OLDSMOBILE BRAVADA WITH 4.3L ENGINE (VIN W - RPO L35)

THIS BULLETIN CONTAINS REVISIONS TO: 1992 OLDSMOBILE/BRAVADA SERVICE MANUAL, PAGE 6E3-A-30 1993 OLDSMOBILE/BRAVADA SERVICE MANUAL, PAGE 6E3-A-34

1992 LIGHT DUTY TRUCKS FUEL AND EMISSIONS, PAGE 3-60 1993 LIGHT DUTY TRUCKS FUEL AND EMISSIONS, PAGE 3D 1994 S/T TRUCK SERVICE MANUAL SUPPLEMENT (WITH RPO CTF) 3A-30 1994 DRIVEABILITY EMISSIONS AND ELECTRICAL DIAGNOSIS MANUALS, S/T PAGE 3A-52, M/L PAGE 3A-36 1995 DRIVEABILITY EMISSIONS AND ELECTRICAL DIAGNOSIS MANUALS, S/T PAGE 3A-50, M/L PAGE 3A-30

**THE TEXT UNDER CIRCUIT DESCRIPTION SHOULD READ:**

THE INJECTOR TESTER IS USED TO TURN "ON" THE INJECTOR AND OPEN THE POPPET NOZZLES FOR A PRECISE AMOUNT OF TIME, THUS SPRAYING A MEASURED AMOUNT OF FUEL INTO THE MANIFOLD. THIS CAUSES A DROP IN FUEL PRESSURE THAT WE CAN RECORD AND COMPARE TO THE PRESSURE DROP SPECIFICATION. AN INJECTOR/POPPET NOZZLE THAT DROPS TO LESS THAN OR EQUAL TO 275 KPA (39 PSI) IS CONSIDERED FAULTY.

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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.