LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 2.0L (LSY) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> Fuel Injector Diagnosis >> Fuel Injector Balance Test

Fuel Injector Balance Test

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  and the CH-47976-500  , 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 .

    • Go to next step: 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).

    • Go to next step: If all fuel injectors are within the recommended tolerance 
  6. All OK.

Fuel Injector Balance Test with Scan Tool

  1. Verify the correct low side fuel pressure. Refer to Fuel System Diagnosis .
  2. Engine idling, observe the Fuel Rail Pressure Sensor parameter with a scan tool. The pressure should be approximately 3 MPa (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. NOTE:

    For engines with 2 banks of cylinders, only measure average pressure drop on cylinders that are on the same bank.

  8. Divide the total pressure drop by the number of fuel injectors that were added together. This is the average pressure drop.
  9. Multiply the average pressure drop by 0.20. This is the acceptable variance from the average pressure drop, 20%.
  10. 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.

    • Go to next step: If within the acceptable variance 
  11. All OK.
scientia non olet · About LEMON Manuals