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Home >> Cadillac >> 2007 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 55 (Engine Controls - System & Component Tests - 2.2L) >> Fuel Systems (Gasoline) >> Fuel Injector Balance Test Using Special Tool >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go toDIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 2.2L ALERO, CAVALIER, GRAND AM (GASOLINE) article.
  2. Did you perform the Fuel Injector Coil Test? If yes, go to next step. If no, go to FUEL INJECTOR COIL TEST .
    3. NOTE: Do not perform this test if the engine coolant temperature is above 201°F (94°C).
  3. Observe the ECT parameter on the scan tool. Does the scan tool indicate that the ECT parameter is less than 201°F (94°C)? If yes, go to next step. If no, allow engine to cool below 201°F (94°C), then go to next step.
    4. NOTE: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic procedure.
  4. Turn ignition switch to OFF position. Turn all accessories OFF. Connect Fuel Pressure Gauge (J 34730-1A), or equivalent, to the fuel pressure connection, located on the fuel rail. See Figure. Turn ignition switch to RUN position, engine OFF. Command the fuel pump ON using a scan tool. The fuel pump may need to be commanded ON a few times to obtain the highest possible fuel pressure. Do not start the engine. Observe the fuel pressure gauge, with the fuel pump commanded ON. Is the fuel pressure 50-60 psi (345-414 kPa)? If yes, go to next step. If no, see FUEL SYSTEM DIAGNOSIS (GASOLINE) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
    5. NOTE: The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant.
  5. Monitor the fuel pressure gauge for one minute. Does the fuel pressure decrease by more than 5 psi (34 kPa)? If yes, see FUEL SYSTEM DIAGNOSIS (GASOLINE) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. If no, go to next step.
    6. CAUTION: Do not repeat any portion of this test before running the engine to prevent the engine from flooding.
  6. Connect the Fuel Injector Tester (J 39021), or equivalent, to a fuel injector using Injector Tester Adapter (J 39021-380), or equivalent. Set the amperage supply selector switch on the fuel injector tester to the BALANCE TEST 0.5-2.5 AMP position. Command the fuel pump relay ON and then OFF using a scan tool. Record the fuel pressure indicated by the fuel pressure gauge after the fuel pressure stabilizes. This is the first pressure reading. The fuel pressure may rise after the fuel injector stops pulsing. Record the fuel pressure value immediately after the fuel injector stops pulsing. Do not record the higher fuel pressure value. Energize the fuel injector by depressing the PUSH TO START TEST button on the fuel injector tester. Record the fuel pressure indicated by the fuel pressure gauge after the fuel injector has stopped pulsing. This is the second pressure reading.

    Repeat procedure for each fuel injector. Subtract the second pressure reading from the first pressure reading for one fuel injector. The result is the pressure drop value. Obtain a pressure drop value for each fuel injector. Add all of the individual pressure drop values. This is the total pressure drop. Divide the total pressure drop by the number of fuel injectors. This is the average pressure drop. Is the difference between any individual pressure drop and the average pressure drop more than 1.5 psi (10 kPa)? If yes, go to next step. If no, see TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

  7. Replace the affected fuel injectors. After repair, go to next step.
  8. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, see TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
Fig 1: Injector Balance Test Example
G00011502Courtesy of GENERAL MOTORS CORP.
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