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Home >> Chevrolet >> 2021 >> Trailblazer RS, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (Engine Controls And Fuel - 1.0L (L4B L4F L4G LIJ) Or 1.2L (L4H L4K LIF LIH) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> Fuel Injector Diagnosis >> {Scan Tool} Fuel Injector Balance Test

{Scan Tool} Fuel Injector Balance Test

WARNING: This page is about a different variant/trim than selected.
    NOTE:

    This diagnostic assumes there are no circuit faults.

  1. Ignition/Vehicle - Off
  2. Disconnect the electrical connector: X160 Inline Harness Connector
    3. NOTE:
    • The component's temperature should be 19 to 21°C (66 to 70°F) while testing.
    • Testing is performed on the component side of the harness connector.
  3. Test for 1.10 to 1.90 ohms between the test points:
    • {Q17A Fuel Injector 1} Control circuit terminal 2 & Control circuit terminal 3 @ X160 Inline Harness Connector
    • {Q17B Fuel Injector 2} Control circuit terminal 4 & Control circuit terminal 5 @ X160 Inline Harness Connector
    • {Q17C Fuel Injector 3} Control circuit terminal 9 & Control circuit terminal 10 @ X160 Inline Harness Connector
    • If not between 1.10 and 1.90 ohms 

      Replace the component: Q17 Fuel Injector

    • Go to next step: If between 1.10 and 1.90 ohms 
  4. Ignition - On/Vehicle - In Service Mode
    5. NOTE:

    The fuel pump may need to be commanded On a few times in order to obtain the highest possible fuel pressure.

  5. Perform the scan tool control function: Fuel Pump Enable - On - Command the function On several times.

    Verify the scan tool parameter: Fuel Pressure Sensor = 320 to 608 kPa (46 to 88 PSI)

    • Go to next step: If between 320 and 608 kPa (46 and 88 PSI) 
  6. Engine - Idling
  7. Verify the scan tool parameter: Fuel Rail Pressure Sensor = 17.5 to 22.5 MPa (2538 to 3263 PSI)
    • Go to next step: If between 17.5 and 22.5 MPa (2538 and 3263 PSI) 
  8. Engine - Running @ 600 to 1000 RPM
    9. NOTE:

    Perform the following test for all 3 components.

  9. Perform the scan tool control function: Fuel Injector Balance - Cylinder 1-3 - Enable - One at a time
  10. Record the value - Fuel Pressure Drop - After each component test.
    11. NOTE:

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

  11. Add all the recorded values, except the suspected faulty component. This is the total pressure drop.
  12. Perform the following steps:
    1. Total pressure drop ÷ Number of components = Average pressure drop
    2. Average pressure drop x 0.20 (20%) = Acceptable variance between components

      Verify the difference between a single pressure drop and the average pressure drop is not greater than the acceptable variance.

    • If greater than the acceptable variance 

      Replace the component: Q17 Fuel Injector

    • Go to next step: If within the acceptable variance 
  13. All OK.
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