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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (Engine Controls And Fuel - 2.4L - DTC P0628 To DTC P2635 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Fuel Injector Balance Test >> Component Testing

Component Testing

WARNING: This page is about a different variant/trim than selected.
NOTE:
  • DO NOT perform this test if the engine coolant temperature (ECT) is above 60°C (140°F). Irregular fuel pressure readings may result due to hot soak fuel boiling.
  • Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic.

Fuel Injector Balance Test with Active Fuel Injector Tester - Preferred Method

  1. Verify the battery is fully charged and all accessories are OFF.
  2. Ignition OFF, all vehicle systems OFF. Install the CH-47976  Active Fuel Injector Tester and the CH-47976-500  Active Fuel Injection Tester (AFIT) SIDI Adapter Kit, refer to the Active Fuel Injector Tester User Guide. It may take up to 2 min for all vehicle systems to power down.
  3. Turn ON the Active Fuel Injector Tester and select the vehicle.
  4. Ignition ON, perform the Injector Test with the Active Fuel Injector Tester.
    • If the Active Fuel Injector Tester aborts testing due to incorrect fuel pressure or fuel leak down 

      Refer to Fuel System Diagnosis .

    • If the Active Fuel Injector Tester does not abort testing 
  5. Compare the test results with the appropriate recommended tolerance.
    • If any fuel injector exceeds the recommended tolerance 

      Replace the appropriate Q17 Fuel Injector(s).

    • If all fuel injectors are within the recommended tolerance 
  6. Perform the Fuel Injector Circuit Diagnosis .

Fuel Injector Balance Test with Scan Tool

  1. Verify the correct low side fuel pressure. Refer to Fuel System Diagnosis .
  2. Engine idling, verify the scan tool Fuel Rail Pressure Sensor parameter is approximately 3MPa (435 psi).
    3. NOTE:

    The engine speed must be between 600-1000 RPM to perform this test.

  3. Select the Fuel Injector Balance function within the Control Functions menu of a scan tool.
  4. Select and test an injector. Repeat for each injector.
  5. Obtain and record a pressure drop value for each injector.
  6. Add all of the individual pressure drop values except for the injector suspected of being faulty. This is the total pressure drop.
  7. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop.
  8. Multiply the average pressure drop by 0.20. This is the acceptable variance from the average pressure drop, 20 percent.
  9. Verify the difference between any individual pressure drop and the average pressure drop is not greater than the acceptable variance.
    • If greater than the acceptable variance 

      Replace the Q17 Fuel Injector.

    • If within the acceptable variance 
  10. Perform the Fuel Injector Circuit Diagnosis .
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