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Home >> Saturn >> 2003 >> Ion 1 Standard >> 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 ION article.
    2. NOTE: Inspect the fuel system for damage or external leaks before proceeding with this diagnostic procedure.
  2. Turn ignition switch to RUN position, 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  .
  3. Verify that adequate fuel is in the fuel tank before proceeding. Turn ignition switch to OFF position. Turn OFF all accessories. Install Gauge Bar Set (SA9127E), or equivalent, with the Fuel Pressure Adapter and the Drain Hose. See Figure . Turn ignition switch to RUN position, engine OFF. DO NOT start the engine. Command the fuel pump relay ON using a scan tool. Observe the fuel pressure gauge with the fuel pump commanded ON. Is the fuel pressure 50-60 psi (345-414 kPa)? If yes, go to step  5 . If no, go to next step.
  4. Is the fuel pressure more than 60 psi (414 kPa)? If yes, go to step  11 . If no, go to step  7 .
  5. Monitor the fuel pressure gauge for 5 minutes. The fuel pressure may vary slightly when the fuel pump stops operating. After the fuel pump stops operating, the fuel pressure should stabilize and remain constant. Does the fuel pressure decrease by more than 8 psi (55 kPa)? If yes, go to step  8 . If no, go to next step.
  6. Turn ignition switch to OFF position. Relieve the fuel pressure. See FUEL SYSTEM PRESSURE RELEASE  . Remove the fuel pressure gauge from the fuel pressure test connection. Disconnect the fuel feed hose from the engine compartment fuel pipe. Connect the fuel feed hose to the inlet side of Fuel Pressure/Flow Adapter (SA9127E-7). Connect the fuel pressure gauge to the fuel pressure/flow adapter. Connect the return hose to the ON/OFF valve side of the fuel pressure/flow adapter. Place the return hose into the fuel filler pipe. Open the valve on the fuel pressure/flow adapter. Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON for a minimum of 10 seconds using a scan tool. Observe the fuel pressure gauge with the fuel pump commanded ON. Is the fuel pressure 50-60 psi (345-414 kPa)? If yes, diagnose by symptom. See SYMPTOMS in TROUBLE SHOOTING - NO CODES - 2.2L ION article. If no, go to next step.
  7. Turn ignition switch to OFF position. Relieve the fuel pressure. See FUEL SYSTEM PRESSURE RELEASE  . Remove any previously installed test equipment. Connect the fuel feed hose to the engine compartment fuel pipe, if previously disconnected. Raise and support the vehicle. Disconnect the fuel feed pipe and the fuel return pipe from the fuel filter. Connect the fuel feed pipe to the inlet side of the Fuel Pressure/Flow Adapter (SA9127E-7). Connect the fuel return pipe to the ON/OFF valve side of the fuel pressure/flow adapter. Connect the fuel pressure gauge to the fuel pressure/flow adapter. Open the valve on the fuel pressure/flow adapter. Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON for a minimum of 10 seconds using a scan tool. Observe the fuel pressure gauge with the fuel pump commanded ON. Is the fuel pressure 50-60 psi (345-414 kPa)? If yes, go to step  9 . If no, go to step  11 .
  8. Turn ignition switch to OFF position. Relieve the fuel pressure. See FUEL SYSTEM PRESSURE RELEASE  . Remove the fuel pressure gauge from the fuel pressure test connection. Disconnect the fuel feed hose from the engine compartment fuel pipe. Connect the fuel feed hose to the inlet side of Fuel Pressure/Flow Adapter (SA9127E-7). Connect the fuel pressure gauge to the fuel pressure/flow adapter. Close the valve on the fuel pressure/flow adapter. Turn ignition switch to RUN position, engine OFF. Command the fuel pump relay ON, for a minimum of 10 seconds using a scan tool. 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  11 . If no, go to step  10 .
  9. Inspect the fuel filter and fuel feed pipe for a restriction. Did you find and correct the condition? If yes, go to step  12 . If no, go to step  11 .
  10. Turn ignition switch to OFF position. Raise the fuel rail with the fuel pipe connected. Turn ON the ignition, engine OFF. Command the fuel pump relay ON using a scan tool. Locate and replace the leaking fuel injector. After repair, go to step  12 .
  11. Replace the fuel sender assembly. After repair, go to step  12 .
  12. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step  3 .
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