For 1990-2009 cars

# SMU - INFORMATION ON FUEL SYSTEM DIAGNOSTICS

#### SUBJECT: INFORMATION ON FUEL SYSTEM DIAGNOSTICS

#### MODELS: 1991-93 CADILLAC DEVILLE, ELDORADO AND SEVILLE EQUIPPED WITH 4.9L ENGINE (VIN B - RPO L26)

THE 1991-93 SERVICE MANUAL SECTION 6E, PFI SYSTEM DIAGNOSIS CHARTS A-4, POWER BALANCE TEST, OR A-5, FUEL PRESSURE AND INJECTOR FLOW MAY INSTRUCT THE SERVICE TECHNICIAN UNDER CERTAIN CONDITIONS TO UNNECESSARILY REPLACE FUEL INJECTOR(S) THAT ARE WITH THE PROPER COMPONENT AND SYSTEM SPECIFICATIONS.

WHEN PERFORMING FUEL SYSTEM DIAGNOSTICS ON 1991-93 4.9L ENGINES (VIN B - RPO L26) USE THE FUEL AND AIR CONTROL SYSTEM DIAGNOSIS CHARTS IN SECTION 6C OF THE 1994 SERVICE MANUAL. PERTINENT CHARTS INCLUDE:

- CHART 6C-1, FUEL SYSTEM CHECK - CHART 6C-2, FUEL PRESSURE CHECK - CHART 6C-3, INJECTOR FLOW / VOLTAGE DROP CHECK - CHART 6C-4, POWER BALANCE CHECK

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GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS ONLY. BULLETINS ARE WRITTEN TO INFORM THOSE TECH- NICIANS OF A CONDITION POSSIBLY OCCURRING ON THE VEHICLE, OR TO PROVIDE INFORMATION ASSISTING IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS, AND TRAINING TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THE BULLETIN APPLIES TO ALL VEHICLES. SEE AN AUTHORIZED GM DEALER FOR INFORMATION ON WHETHER A SPECIFIC VEHICLE MAY BENEFIT FROM THE INFORMATION.

COPYRIGHT 1994. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.