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Home >> Chevrolet >> 2018 >> Spark LT, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 35 (Engine Controls And Fuel - 1.4L (LV7) - DTC P0351 To DTC P2544 And Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Fuel System Diagnosis >> Circuit/System Verification

Circuit/System Verification

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NOTE:
  • Inspect the fuel system for damage or external leaks before proceeding.
  • Verify that adequate fuel is in the fuel tank before proceeding.
  • The Fuel Pump Relay may need to be commanded On a few times in order to obtain the highest possible fuel pressure.
  • Before proceeding with this test review the User Manual EN-34730-5 for Safety Information and Instructions.
  1. Ignition ON.
  2. Verify that the fuel pump turns ON and OFF when commanding the Fuel Pump Relay On and Off with a scan tool.
    • If the fuel pump does turn ON and OFF 
  3. Ignition OFF, all accessories OFF, install a EN-34730-91  .
  4. Ignition ON, engine OFF.
  5. Command the Fuel Pump Relay On several times with a scan tool.
  6. Verify the fuel pressure is between 345 - 414 kPa (50 - 60 psi) with the fuel pump running.
    • If less than 345 kPa (50 psi) 

      Refer to Circuit/System Testing - Fuel Pressure Low.

    • If greater than 414 kPa (60 psi) 

      Replace the G12 Fuel Pump.

    • If between 345 - 414 kPa (50 - 60 psi) 
  7. Verify that the fuel pressure does not decrease more than 34 kPa (5 psi) in 1 min.
    • If greater than 34 kPa (5 psi) 

      Refer to Circuit/System Testing - Fuel Pressure Leaks Down.

    • If less than 34 kPa (5 psi) 
  8. Relieve the fuel pressure to 69 kPa (10 psi).
  9. Verify that the fuel pressure does not decrease more than 14 kPa (2 psi) in 5 min.
    • If greater than 14 kPa (2 psi) 

      Replace the G12 Fuel Pump.

    • If less than 14 kPa (2 psi) 
  10. Operate the vehicle within the conditions of the customer's concern while monitoring the fuel pressure with the EN-34730-91  .
  11. Verify the fuel pressure does not drop off during acceleration, cruise or hard cornering.
    • If the fuel pressure drops off 

      Refer to Circuit/System Testing - Fuel Pressure Drops Off.

    • If the fuel pressure does not drop off 
  12. If the fuel system components test normal, refer to Symptoms - Engine Controls , and Fuel Injector Diagnosis .
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