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Home >> Chevrolet >> 2018 >> Equinox L >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (Engine Controls And Fuel - 1.6L (LH7) Diesel - Diagnostic Information And Procedures (P205B - P2BAA) And Symptoms) >> Diagnostic Information And Procedures >> Fuel System Diagnosis - High Pressure Side >> Circuit/System Testing

Circuit/System Testing

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  1. Ignition Off.
  2. Verify there are no external leaks or damage to the fuel return and supply lines.
    • Go to next step: If no external leaks or damage is found 
  3. Verify that adequate fuel is in the fuel tank before proceeding.
  4. Engine cranking or running, verify scan tool parameter Fuel Pressure Sensor is between 370-450 kPa (54-65 PSI).
    • Go to next step: If within 370-450 kPa (54-65 PSI) 
  5. Ignition Off, disconnect all the glow plug harness connector nuts and remove the glow plugs.
  6. Using a scan tool, enable the control function Compression Test.
  7. Hold a clean rag over the glow plug holes.
  8. Crank the engine for 6 compression strokes. No fuel vapor should be emitted onto the rag.
    • If fuel vapor is emitted 

      Replace the appropriate Q17 Fuel Injector.

    • Go to next step: If fuel vapor is not emitted 
  9. Disconnect the Q18B Fuel Pressure Regulator 2 return hose and plug the hose to prevent fuel leakage.
  10. Install a section of rubber fuel hose on the fuel pressure regulator 2 outlet and place the loose end of hose into a clean fuel container.
  11. Perform the applicable test listed below:

    ENGINE NO START:

    1. Engine cranking for 15 seconds.
    2. Observe the volume of fuel from fuel pressure regulator 2. The volume of fuel should be less than 10 ml (0.4 oz).
      • If greater than 10 ml (0.4 oz), replace Q18B Fuel Pressure Regulator 2.
      • If less than 10 ml (0.4 oz)
      3. NOTE:
      • Perform the following two Sub-Steps for each injector.
      • Complete the following two Sub-Steps on all of the fuel injectors before performing any repairs.
    3. Disconnect the electrical connector and the fuel return line from one of the fuel injectors.
    4. Engine Cranking for 15 seconds, verify no fuel leaks from the fuel injector.
      • If fuel leaks from the fuel injector, replace the appropriate Q17 Fuel Injector.
      • If no fuel leaks from the fuel injector, replace the G18 High Pressure Fuel Pump.

    ENGINE STARTS:

    1. Disconnect the Q18B Fuel Pressure Regulator 2 return hose and plug the hose to prevent fuel leakage.
    2. Install a section of rubber fuel hose on the fuel pressure regulator 2 outlet and place the loose end of hose into a clean fuel container.
    3. Engine at idle.
    4. Fuel temperature must be greater than -25°C (-13°F)
    5. Engine at a stable idle.
    6. Engine at normal operating temperature.
      7. NOTE:

      Engine speed greater than 1800 RPM will cause incorrect test results.

    7. Slowly increase engine speed to 1700 RPM and then back to idle within 15 s.
    8. Observe the volume of fuel from fuel pressure regulator 2. The volume of fuel should be less than 10 ml (0.4 oz).
      • If greater than 10 ml (0.4 oz), replace Q18B Fuel Pressure Regulator 2.
      • If less than 10 ml (0.4 oz)
    9. Reconnect the Q18B Fuel Pressure Regulator 2 return line.
    10. Engine Idling.
      11. NOTE:

      When commanding fuel rail pressure at idle the maximum achievable pressure will be approximately 120 MPa (17405 psi).

    11. Command the fuel pressure incrementally through the entire fuel pressure range with a scan tool.
    12. Verify the scan tool Fuel Rail Pressure Sensor 1 and the Desired Fuel Rail Pressure are within 2000 kPa (290 psi) for the entire fuel pressure range and note results.
      • If the fuel pressure parameters are not within 2000 kPa (290 psi) 

        Replace the Q18A Fuel Pressure Regulator 1.

      • Go to next step: If the fuel pressure parameters are within 2000 kPa (290 psi) 
    13. Replace the G18 High Pressure Fuel Pump.
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