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Fuel System Diagnosis: Metro

  1. Perform diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK in SELF-DIAGNOSTICS - METRO article. Repair any faults identified and go to next step.
  2. Turn ignition off and relieve fuel pressure. See FUEL SYSTEM PRESSURE RELEASE . Place shop towel around fuel feed hose at chassis fuel feed pipe, and disconnect fuel feed hose from feed pipe.
  3. Install Fuel Rail Adapter (J-34730-75) to fuel feed pipe and attach fuel feed hose to adapter with hose clamp. Connect Fuel Pressure Gauge (J-34730-1A) to adapter. Ensure fuel tank has adequate supply of fuel. Connect negative battery cable. Turn ignition on (engine off). Fuel pump should operate for about 2 seconds. If any fuel pressure is indicated, go to next step. If any fuel pressure is not indicated, go to step  14.
    4. NOTE: It may be necessary to cycle ignition from off to on several times to obtain maximum fuel pressure.
  4. Turn ignition off. Turn ignition on (engine off). Fuel pump should operate for about 2 seconds. During 2-second fuel pump operation, check fuel pressure reading. If fuel pressure is between 38.5-44 psi (2.7-3.1 kg/cm2 ), go to next step. If fuel pressure is not between 38.5-44 psi (2.7-3.1 kg/cm2 ), go to step  12.
  5. Turn ignition off. Observe fuel pressure gauge for one minute after fuel pump stops operating. If fuel pressure holds at 28.5 psi (2 kg/cm2 ) or greater, go to next step. If fuel pressure does not hold at 28.5 psi (2 kg/cm2 ) or greater, go to step  8.
  6. Start engine. If engine starts and runs, go to next step. If engine does not start and run, go to FUEL INJECTOR CIRCUIT DIAGNOSIS .
  7. Warm engine to normal operating temperature and check fuel pressure. If fuel pressure is not 28.5-35 psi (2-2.5 kg/cm2 ), go to step  10. If fuel pressure is 28.5-35 psi (2-2.5 kg/cm2 ), system is okay at this time.
  8. Check fuel injectors, fuel feed pipes and hoses for leaks and repair as necessary. If no leaks are located and repaired, go to next step. If leaks are located and repaired, go to step  20.
  9. Turn ignition on (engine off). Fuel pump should operate for about 2 seconds. Immediately after fuel pump stops operating, observe fuel pressure reading while pinching fuel feed hose between fuel pressure gauge and fuel pump. If fuel pressure reading does not hold at 38.5 psi (2.7 kg/cm2 ) or greater, go to next step. If fuel pressure does hold at 38.5 psi (2.7 kg/cm2 ) or greater, go to step  19.
  10. Turn ignition on (engine off). Fuel pump should operate for about 2 seconds. Observe fuel pressure reading while pinching fuel return hose. If fuel pressure reading does not hold at 38.5 psi (2.7 kg/cm2 ) or greater, go to next step. If fuel pressure does hold at 38.5 psi (2.7 kg/cm2 ) or greater, go to step  18.
  11. Check for faulty or incorrectly operating fuel injectors. See FUEL INJECTOR CIRCUIT DIAGNOSIS . Check for a leaking fuel pressure regulator. Repair or replace faulty fuel injector or fuel pressure regulator. After repair, go to step  20.
  12. If fuel pressure is less than 38.5 psi (2.7 kg/cm 2 ), go to next step. If fuel pressure is not less than 38.5 psi (2.7 kg/cm 2 ), go to step  16.
    13. NOTE: It may be necessary to cycle ignition from off to on several times to obtain maximum fuel pressure.
  13. Turn ignition on (engine off). Fuel pump should operate for about 2 seconds. Observe fuel pressure reading while pinching fuel return hose. If fuel pressure reading does not hold at 64 psi (4.5 kg/cm2 ) or greater, go to next step. If fuel pressure does hold at 64 psi (4.5 kg/cm2 ) or greater, go to step  18.
  14. If fuel pump control circuit diagnostic procedure was performed, go to next step. If fuel pump control circuit diagnostic procedure was not performed, go to FUEL PUMP CONTROL CIRCUIT DIAGNOSIS .
  15. Check for any of the following conditions:
    • Restricted fuel feed pipe.
    • Restricted fuel feed hose.
    • Restricted fuel filter.
    • Restricted or leaking fuel feed pipes, hoses or connections inside fuel tank assembly.
    • Verify battery voltage is available at fuel pump connector and that resistance of ground circuit is less than 5 ohms. See WIRING DIAGRAMS article.
    Repair identified fault as required. If no repairs were necessary, go to step  19. If repairs were necessary, go to step  20.
  16. Turn ignition off and relieve fuel pressure. See FUEL SYSTEM PRESSURE RELEASE . Place shop towel around fuel pressure regulator and disconnect fuel return hose from regulator. Connect a new fuel hose to fuel pressure regulator and insert other end of hose in approved container. Turn ignition on (engine off). If fuel pressure is between 38.5-44 psi (2.7-3.1 kg/cm2 ), go to next step. If fuel pressure is not between 38.5-44 psi (2.7-3.1 kg/cm2 ), go to step  18.
  17. Repair or replace restricted fuel return hose/pipe. After repair, go to step  20.
  18. Replace fuel pressure regulator. After repair, go to step  20.
  19. Replace fuel pump. After repair, go to next step.
  20. Operate vehicle under same conditions as recorded for original symptom. If system operates properly, system is okay at this time. If system does not operate properly, check fuel pump and for presence of water contamination of fuel. See SYSTEM & COMPONENT TESTING - CARS - METRO & PRIZM article.
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