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Home >> Chevrolet >> 2015 >> Cruze LT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 14 (Engine Controls And Fuel - 2.0L (LUZ) Diesel - DTC P2122 To DTC P2689 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Fuel System Diagnosis - High Pressure Side >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
NOTE:
  • If you were not referred to this test from another diagnostic, do not perform this procedure.
  • Only perform this test when the fuel temperature is warmer than 18°C (65°F).
  1. Ignition OFF.
  2. Verify there are no external leaks or damage to the fuel return and supply lines.
    • If no external leaks or damage is found 
  3. Disconnect the supply hose at the G18 High Pressure Fuel Pump.
  4. Connect the J-37287  Fuel Line Shut-off Adapter to the supply hose and place the other end of the hose into a suitable container.
  5. Ignition ON.
  6. Command the fuel pump on for 30 s
  7. Verify at least 1200 mL (40.2 oz) of fuel is in the container.
    • If greater than 1200 mL (40.2 oz) 
  8. Reconnect the supply hose at the G18 High Pressure Fuel Pump.
  9. Ignition OFF, disconnect all the glow plug harness connector nuts and remove the glow plugs.
  10. Hold a clean rag over the glow plug holes.
  11. Using a remote start switch, crank the engine for 6 compression strokes. No fuel vapor should be emitted onto the rag.
    CAUTION: Do not crank the engine using the ignition switch, as the fuel injectors and the glow plug circuits will be energized and engine damage may result.
    • If fuel vapor is emitted onto the rag 

      Replace the appropriate Q17 Fuel Injector.

    • If fuel vapor is not emitted onto the rag 
  12. Disconnect the Q18B Fuel Pressure Regulator 2 return hose and plug the hose to prevent fuel leakage.
  13. 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.
  14. 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 the Fuel Injection Fuel Rail Assembly.
      • If less than 10 ml (0.4 oz)
    3. Disconnect the electrical connector and the fuel return line from one of the fuel injectors. Install the CH-50377-A  Fuel Injector Return Line Plug to the return line to prevent leakage.
      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.
    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
    5. Disconnect the harness connector at the Q18B Fuel Pressure Regulator 2.
    6. Crank the engine for 15 second.
    7. Verify a steady flow of fuel comes out of the Q18B Fuel Pressure Regulator 2 outlet.
      • If there is not a steady flow of fuel, replace the G18 High Pressure Fuel Pump.
      • If there is a steady flow of fuel.
    8. Reconnect the harness connector and return line at Q18B Fuel Pressure Regulator 2.
    9. Install the CH-50375  Fuel Injector Return Line Adaptor with a gauge to a fuel injector return line.
    10. Engine cranking.
    11. Verify the injector return line pressure is greater than 3 bar (44 psi).
      • If greater than 3 bar (44 psi)
    12. Test the fuel injector return flow, refer to Fuel Injector Diagnosis .
      • If a faulty fuel injector is found, replace the appropriate Q17 Fuel Injector.
      • If the fuel injectors test normal
    13. Replace the G18 High Pressure Fuel Pump.

    ENGINE STARTS:

    1. Engine at idle.
      NOTE: At engine start, fuel pressure regulator 2 controls fuel pressure at idle. The engine will remain in this mode if the fuel temperature is below 15°C (59°F) or until fuel pressure regulator 2 adapts (which occurs at higher engine loads) or until fuel temperature reaches 60°C (140°F). Once the adaptation is complete, the vehicle will use fuel pressure regulator 1 to control rail pressure.
    2. Fuel temperature must be greater than 15°C (59°F)
    3. Using the scan tool, command the Fuel Rail Pressure to 60 MPa (8702 psi) for 15 seconds. This allows the Q18B Fuel Pressure Regulator 2 adaptation process to complete.
    4. Engine at a stable idle.
    5. Slowly increase engine speed to 1700 RPM and then back to idle within 15 s.
      NOTE: Engine speed greater than 1800 RPM will cause incorrect test results.
    6. 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 the Fuel Injection Fuel Rail Assembly.
      • If less than 10 ml (0.4 oz)
    7. Reconnect the Q18B Fuel Pressure Regulator 2 return line.
    8. Engine Idling.
    9. Command the fuel pressure incrementally through the entire fuel pressure range with a scan tool.
      NOTE: When commanding fuel rail pressure at idle the maximum achievable pressure will be approximately 60 MPa (8702 psi).
    10. Verify the scan tool Fuel Pressure Sensor and the Desired Fuel Rail Pressure are within 690 kPa (100 psi) for the entire fuel pressure range and note results.
      • If the fuel pressure parameters are not within 690 kPa (100 psi) 

        Replace the Q18A Fuel Pressure Regulator 1.

      • If the fuel pressure parameters are within 690 kPa (100 psi) 
    11. Engine OFF.
    12. Install the CH-50375  Fuel Injector Return Line Adaptor with a gauge to a fuel injector return line.
    13. Engine idling.
    14. Verify the injector return line pressure is greater than 3 bar (44 psi).
      • If greater than 3 bar (44 psi)
    15. Test the fuel injector return flow, refer to Fuel Injector Diagnosis .
      • If a faulty fuel injector is found, replace the appropriate Q17 Fuel Injector.
      • If the fuel injectors test normal
    16. Replace the G18 High Pressure Fuel Pump.
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