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Home >> Saturn >> 2003 >> L200 Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures >> Fuel Systems >> Fuel System Diagnosis >> Diagnostic Procedure
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Diagnostic Procedure

  1. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 2.2L SATURN "L" SERIES article.
    2. NOTE: Inspect the fuel system for damage or external leaks before proceeding with this diagnostic.
  2. Turn ignition on, with engine off. Command the fuel pump relay ON using a scan tool. Does the fuel pump operate? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS in SYSTEM & COMPONENT TESTING - 2.2L SATURN "L" SERIES article.
    3. NOTE: Verify that adequate fuel is in the fuel tank before proceeding with this diagnostic test.
  3. Turn ignition on, with engine off. Remove hose from the fuel pressure regulator. Command the fuel pump relay ON with a scan tool. Inspect for a fuel leak from fuel pressure regulator port. Is fuel pressure regulator leaking fuel? If yes, go to step  25 . If no, go to next step.
  4. Command the fuel pump relay OFF with a scan tool. Turn ignition off. Turn OFF all accessories. Install Gauge Bar Set (SA9127E) with the Fuel Pressure Adapter and the Drain Hose. Turn ignition on, with engine off. DO NOT start engine. Command the fuel pump relay ON with a scan tool. Observe the fuel pressure gauge with the fuel pump commanded ON. Is the fuel pressure within 50-60 psi (345-414 kPa)? If yes, go to next step. If no, go to step  9 .
    5. NOTE: The fuel pressure may vary slightly when fuel pump stops operating. After fuel pump stops operating, the fuel pressure should stabilize and remain constant.
  5. Monitor the fuel pressure gauge for 5 minutes. Does the fuel pressure decrease by more than 8 psi (55 kPa)? If yes, go to step  7 . If no, go to next step.
  6. Operate the vehicle within the conditions to reproduce the original symptoms. Monitor the O2 and Fuel Trim parameters with scan tool. Do the scan tool parameters indicate a lean condition? If yes, go to step  13 . If no, go to SYMPTOMS in TROUBLE SHOOTING - NO CODES - 2.2L SATURN "L" SERIES article.
  7. Turn ignition off. Relieve fuel pressure. Remove fuel pressure gauge from the fuel pressure test connection. Disconnect the chassis fuel hoses from engine compartment fuel pipes. Connect the fuel feed hose to the inlet side of Fuel Pressure/Flow Adapter (SA9127E-7) using the 3/8" Male Fuel Pressure Adapter Line (J 43937). Connect the fuel return hose to the outlet side of Fuel Pressure/Flow Adapter using the 5/16" Male Fuel Pressure Adapter Line (J 43937). Close the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Record fuel pressure. Command the fuel pump relay OFF. Monitor the fuel pressure gauge for 5 minutes. Does the fuel pressure decrease by more than 8 psi (55 kPa)? If yes, go to step  27 . If no, go to next step.
  8. Turn ignition off. Open the valve on the Fuel Pressure/Flow Adapter. Disconnect the fuel feed hose from the inlet side of Fuel Pressure/Flow Adapter. Connect the fuel feed hose to the engine compartment fuel pipe. Connect the fuel rail side of the engine compartment fuel return pipe to the inlet side of Fuel Pressure/Flow Adapter using the 5/16" Female Fuel Pressure Adapter Line (J 43937). Close the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Record fuel pressure. Command the fuel pump relay OFF. Monitor the fuel pressure gauge for 5 minutes. Does the fuel pressure decrease by more than 8 psi (55 kPa)? If yes, go to step  20 . If no, go to step  25 .
  9. Is the fuel pressure more than 60 psi (414 kPa)? If yes, go to next step. If no, go to step  13 .
  10. Turn ignition off. Relieve fuel pressure. Disconnect the fuel return hose from engine compartment fuel return pipe. Connect the fuel rail side of the engine compartment fuel return pipe to the inlet side of Fuel Pressure/Flow Adapter using the 5/16" Female Fuel Pressure Adapter Line (J 43937). Connect return hose from the Fuel Pressure/Flow Adapter to the outlet side of the Fuel Pressure/Flow Adapter. Place the other end of the return hose into the fuel filler pipe. Cap pressure test port on the Fuel Pressure/Flow Adapter with the Fuel Pressure Adapter Cap (J 43936). Open the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Monitor the fuel pressure gauge while the fuel pump is operating. Is the fuel pressure less than 75 psi (517 kPa)? If yes, go to next step. If no, go to step  17 .
  11. Turn ignition off. Relieve fuel pressure. Remove the Fuel Pressure/Flow Adapter (SA9127E-7). Connect the fuel return hose to the engine compartment fuel return pipe. Raise vehicle. Disconnect the chassis fuel return pipe at the passenger-side front wheel well area. Connect the engine side of the fuel return pipe to the inlet side of Fuel Pressure/Flow Adapter using the 5/16" Female Fuel Pressure Adapter Line (J 43937). Connect the return hose from the Fuel Pressure/Flow Adapter to the outlet side of Fuel Pressure/Flow Adapter. Place the other end of the return hose into the fuel filler pipe. Cap the pressure test port on the Fuel Pressure/Flow Adapter. Open the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Monitor the fuel pressure gauge while fuel pump is operating. Is fuel pressure less than 75 psi (517 kPa)? If yes, go to next step. If no, go to step  22 .
  12. Turn ignition off. Relieve fuel pressure. Remove the Fuel Pressure/Flow Adapter. Connect the chassis fuel return pipe at the passenger side front wheel well area. Remove the fuel pipe shield. Disconnect the fuel return pipe at the front of the fuel tank. Connect the engine side of the fuel return pipe to the inlet side of Fuel Pressure/Flow Adapter using the 5/16" Female Fuel Pressure Adapter Line. Connect the return hose from the Fuel Pressure/Flow Adapter to the outlet side of Fuel Pressure/Flow Adapter. Place the other end of the return hose into the fuel filler pipe. Cap the pressure test port on the Fuel Pressure/Flow Adapter. Open valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Monitor the fuel pressure gauge while the fuel pump is operating. Is the fuel pressure less than 75 psi (517 kPa)? If yes, go to step  19 . If no, go to step  24 .
  13. Turn ignition off. Relieve fuel pressure. Remove the fuel pressure gauge from the fuel pressure test connection. Disconnect the chassis fuel hoses from the engine compartment fuel pipes. Connect the fuel feed hose to the inlet side of Fuel Pressure/Flow Adapter using the 3/8" Male Fuel Pressure Adapter Line (J 43937). Connect the fuel return hose to the outlet side of Fuel Pressure/Flow Adapter using the 5/16" Male Fuel Pressure Adapter Line (J 43937). Connect the fuel pressure gauge to the Fuel Pressure/Flow Adapter. Open the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Is the fuel pressure more than 55 psi (379 kPa)? If yes, go to step  25 . If no, go to next step.
  14. Turn ignition off. Remove the Fuel Pressure/Flow Adapter. Connect the chassis fuel hoses to the engine compartment fuel pipes. Raise vehicle. Disconnect the fuel feed pipe at the fuel filter inlet. Connect the fuel feed pipe to the inlet side of Fuel Pressure/Flow Adapter using the 3/8" Male Fuel Pressure Adapter Line (J 43937). Connect the return hose from the Fuel Pressure/Flow Adapter to the outlet side of Fuel Pressure/Flow Adapter. Place the other end of the return hose into the fuel filler pipe. Open the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Is the fuel pressure more than 55 psi (379 kPa)? If yes, go to next step. If no, go to step  18 .
  15. Turn ignition off. Remove the Fuel Pressure/Flow Adapter from the fuel filter inlet. Connect the fuel feed pipe to the fuel filter inlet. Disconnect the fuel feed pipe at the fuel filter outlet. Connect the inlet side of Fuel Pressure/Flow Adapter to the fuel filter outlet using the 3/8" Female Fuel Pressure Adapter Line. Open the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Is the fuel pressure more than 55 psi (379 kPa)? If yes, go to next step. If no, go to step  26 .
  16. Turn ignition off. Remove the Fuel Pressure/Flow Adapter from the fuel filter outlet. Connect the fuel feed pipe to the fuel filter outlet. Disconnect the chassis fuel feed pipe at the passenger-side front wheelwell area. Connect the fuel tank side of the fuel feed pipe to the inlet side of Fuel Pressure/Flow Adapter using the 3/8" Male Fuel Pressure Adapter Line (J 43937). Open the valve on the Fuel Pressure/Flow Adapter. Turn ignition on, with engine off. Command the fuel pump relay ON for a minimum of 10 seconds with a scan tool. Is the fuel pressure more than 55 psi (379 kPa)? If yes, go to step  21 . If no, go to step  23 .
  17. Inspect fuel rail return pipe and fuel rail outlet passage for a restriction. Did you find and correct the condition? If yes, go to step  28 . If no, go to step  25 .
  18. Inspect rear fuel feed pipe on fuel tank for damage and for a restriction. Did you find and correct the condition? If yes, go to step  28 . If no, go to step  27 .
  19. Inspect rear fuel return pipe on fuel tank for a restriction. Did you find and correct the condition? If yes, go to step  28 . If no, go to step  27 .
  20. Turn ignition off. Open the valve on the Fuel Pressure/Flow Adapter. Remove the Fuel Pressure/Flow Adapter from the fuel return pipe. Connect the fuel return hose to the engine compartment fuel pipe. Raise fuel rail, with fuel lines connected. Turn ignition on, with engine off. Command the fuel pump relay ON with a scan tool. Locate and replace the leaking fuel injector. After replacement, go to step  28 .
  21. Replace engine compartment fuel feed pipe. After replacement, go to step  28 .
  22. Replace engine compartment fuel return pipe. After replacement, go to step  28 .
  23. Replace chassis fuel feed pipe. After replacement, go to step  28 .
  24. Replace chassis fuel return pipe. After replacement, go to step  28 .
    25. NOTE: Inspect for a missing or damaged O-ring seal before replacing the fuel pressure regulator.
  25. Replace fuel pressure regulator. After replacement, go to step  28 .
  26. Replace fuel filter. After replacement, go to step  28 .
  27. Replace fuel sender. After replacement, go to step  28 .
  28. Operate the system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step  4 .
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