LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 119 (Engine Control System - Basic Diagnostic Procedures) >> No-Start Diagnosis >> No Start - Engine Cranks Okay (3.5L - Intrigue) >> Fuel System Diagnosis

Fuel System Diagnosis

WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2002 Saturn SL2, 2002 Saturn SL1, 2002 Saturn SL, 2002 Saturn SC2, and 2002 Saturn SC1. However, it is still accessible from the selected car via links, so may be relevant.
  1. If diagnostic system check has already been performed, go to next step. If diagnostic system check has not been performed, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS in appropriate SELF-DIAGNOSTICS article.
    2. NOTE: Inspect fuel system for damage or external leaks, before proceeding with this test.
  2. Turn ignition on, with engine off. Using scan tool, command fuel pump on. Does fuel pump operate? If yes, go to next step. If no, go to FUEL PUMP ELECTRICAL CIRCUIT DIAGNOSIS .
    3. NOTE: Verify that there is adequate fuel in fuel tank before proceeding with this test.
    CAUTION: Wrap shop towel around fuel pressure connection in order to reduce the risk of fire and personal injury.
  3. Turn ignition and all accessories off. Install Fuel Pressure Gauge (J-34730-1A). Place fuel pressure gauge bleed hose into an approved gasoline container. Turn ignition on, with engine off. Using scan tool, command fuel pump on. Bleed air out of fuel pressure gauge. You may need to command the fuel pump on several times in order to obtain the highest possible fuel pressure. DO NOT start engine. Observe fuel pressure gauge with fuel pump commanded on. Is fuel pressure within 41-47 psi (2.9-3.3 kg/cm2 ). If yes, go to next step. If no, go to step  12.
  4. The fuel pressure may vary slightly when fuel pump stops running. After fuel pump stops running, fuel pressure should stabilize and remain constant. Monitor fuel pressure gauge for one minute. Does fuel pressure drop more than 5 psi (0.4 kg/cm2 )? If yes, go to step  9. If no, go to next step.
  5. Relieve fuel pressure to 10 psi (0.7 kg/cm 2 ). Monitor fuel pressure gauge for 5 minutes. Does fuel pressure drop more than 2 psi (0.1 kg/cm 2 )? If yes, go to step  24. If no, go to step next.
  6. Turn ignition off for 15 seconds. Turn ignition on, with engine off. Monitor fuel pressure gauge. Start engine. Does fuel pressure drop to 3-10 psi (0.2-0.7 kg/cm2 ) when engine is started? If yes, go to next step. If no, go to step  8.
  7. Operate vehicle within the conditions of the customer's concern. Monitor fuel related parameters with a scan tool. Do any of the scan tool parameters indicate a lean condition? If yes, go to step  17. If no, problem is intermittent. See appropriate TROUBLE SHOOTING - NO CODES article.
  8. Disconnect vacuum hose from fuel pressure regulator. Monitor fuel pressure gauge. Operate engine at idle. Using a hand-held vacuum pump, apply 12-14 in. Hg (40 kPa) to fuel pressure regulator. Does fuel pressure drop to 3-10 psi (0.2-0.7 kg/cm2 ) when vacuum is applied? If yes, go to step  21. If no, go to step  23.
  9. Turn ignition off. Disconnect vacuum hose from fuel pressure regulator. Turn ignition on, with engine off. Using scan tool, command fuel pump on. Inspect for fuel leak at fuel pressure regulator vacuum port. Is fuel pressure regulator leaking fuel? If yes, go to step  23. If no, go to next step.
  10. Turn ignition off. Relieve fuel pressure. Disconnect fuel feed hose and fuel return hose from fuel rail pipes. Install Fuel Pipe Shut-Off Adapters (J-37287) between fuel hoses and fuel rail pipes. Open valves on fuel pipe shut-off adapters. Turn ignition on, with engine off. Command fuel pump on with scan tool. Bleed air from fuel pressure gauge. Command fuel pump on and then off with scan tool. Close fuel feed pipe shut-off valve. Monitor fuel pressure gauge for one minute. Does fuel pressure remain constant? If yes, go to step  19. If no, go to next step.
  11. Turn ignition off. Open fuel feed pipe shut-off valve. Turn ignition on, with engine off. Command fuel pump on and then off with scan tool. Close fuel return pipe shut-off valve. Monitor fuel pressure gauge for one minute. Does fuel pressure remain constant? If yes, go to step  23. If no, go to step  20.
  12. Is fuel pressure greater than 62 psi (4.4 kg/cm 2 )? If yes, go to step  14. If no, go to next step.
  13. Is fuel pressure greater than zero psi? If yes, go to step  16. If no, go to step  17.
  14. Turn ignition off. Relieve fuel pressure. Disconnect fuel return hose from fuel rail pipe. Attach a length of flexible fuel hose to fuel rail outlet passage. Place open end of fuel hose into an approved gasoline container. Turn ignition on, with engine off. Monitor fuel pressure gauge while fuel pump is operating. Is fuel pressure within 41-47 psi (2.9-3.3 kg/cm 2 )? If yes, go to step  22. If no, go to next step.
  15. Inspect fuel return pipe and fuel rail outlet passage for a restriction. Did you find and correct the condition? If yes, go to step  25. If no, go to step  23.
  16. Turn ignition off. Relieve fuel pressure. Disconnect fuel return hose from fuel rail pipe. Install Fuel Pipe Shut-off Adapters (J-37287) between fuel return pipe and fuel rail. Open valve in fuel pipe shut-off adapter. Turn ignition on, with engine off. Command fuel pump on with scan tool. Bleed air from fuel system. Monitor fuel pressure gauge. DO NOT allow fuel pressure to exceed 75 psi (5.3 kg/cm2 ). Excessive pressure may damage fuel system. Slowly close valve in fuel return pipe shut-off adapter. Command fuel pump on with scan tool. Does fuel pressure increase to more than 47 psi (3.3 kg/cm 2 )? If yes, go to step  23. If no, go to next step.
  17. Check for a restricted fuel filter or fuel feed pipe. Did you find and correct the condition? If yes, go to step  25. If no, go to next step.
  18. Inspect fuel pump harness connectors and ground circuits for poor connections. Did you find and correct the condition? If yes, go to step  25. If no, go to next step.
  19. Remove fuel sender assembly. Check fuel pump flex hose for damage, in-tank fuel pump harness connectors for poor connections, fuel strainer for a restriction or contaminates in fuel tank. Did you find and correct the condition? If yes, go to step  25. If no, go to step  24.
  20. Turn ignition off. Raise fuel rail with fuel lines connected. Turn ignition on, with engine off. Command fuel pump on with scan tool. Locate and replace leaking fuel injector. After repairs, go to step  25.
  21. Repair vacuum source to fuel pressure regulator. After repairs, go to step  25.
  22. Locate and repair restricted fuel return line. After repairs, go to step  25.
  23. Replace fuel pressure regulator. After replacing fuel pressure regulator, go to step  25.
  24. Replace fuel pump. After replacing fuel pump, go to next step.
  25. Operate system in order to verify the repair. Did you correct the condition? If yes, system is okay. If no, go to step  3.
scientia non olet · About LEMON Manuals