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Home >> Isuzu >> 2004 >> Ascender LS, 5.3 P, 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls (Introduction) - 5.3L >> Repair Instructions >> Fuel Rail Assembly Replacement >> Removal Procedure
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Removal Procedure

  1. Remove the air cleaner outlet duct. Refer to Air Cleaner Resonator Outlet Duct Replacement .
    2. IMPORTANT: An eight-digit identification number (1) is located on the fuel rail. Refer to this model identification number if servicing or part replacement is required.
    Fig 1: Locating Fuel Rail Eight-Digit ID Number
    GM380659Courtesy of GENERAL MOTORS CORP.
  2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure .
    3. Fig 2: View Of A/C Compressor Pressure Switch Electrical Connector & Retaining Clip
    GM898468Courtesy of GENERAL MOTORS CORP.
  3. Disconnect the air conditioning (A/C) compressor pressure switch electrical connector (2).
  4. Remove the wire harness from the clip (1) on the cylinder head.
    5. Fig 3: View Of MAF/IAT Sensor Electrical Connector
    GM1204792Courtesy of GENERAL MOTORS CORP.
  5. Disconnect the mass air flow (MAF)/intake air temperature(IAT) sensor electrical connector (1).
    6. Fig 4: View Of Generator Electrical Connector
    GM898329Courtesy of GENERAL MOTORS CORP.
  6. Disconnect the generator electrical connector.
    7. Fig 5: Locating Electrical Components At Top Of Engine
    GM898331Courtesy of GENERAL MOTORS CORP.
  7. Disconnect the following electrical connectors on the right hand side of the engine:
    • Coil main electrical harness (1)
    • Electronic throttle control (ETC) (2)
    • Fuel injectors (3)
    8. Fig 6: View Of CPA Retainer
    GM1209783Courtesy of GENERAL MOTORS CORP.
  8. Perform the following steps in order to disconnect the fuel injector electrical connectors.
    1. Mark the connectors to their corresponding injectors to ensure correct reassembly.
    2. Pull the connector position assurance (CPA) retainer (2) on the connector up 1 click.
    3. Push the tab (1) on the connector in.
    4. Disconnect the fuel injector electrical connector.
    5. Repeat the steps for each injector electrical connector.
  9. Remove the electrical harness from the clips on ignition coil bracket.
    10. Fig 7: Top Of Engine Wiring Harness View
    GM898326Courtesy of GENERAL MOTORS CORP.
  10. Disconnect the following electrical connectors on the left hand side of the engine:
    • Evaporative emission (EVAP) purge solenoid (1)
    • Knock sensor (2)
    • Manifold absolute pressure (MAP) sensor (3)
    • Main coil (5)
    • Fuel injectors (4).
  11. Remove the electrical harness from the clips on ignition coil bracket.
    12. Fig 8: Breather Crossover Tube View
    GM647793Courtesy of GENERAL MOTORS CORP.
  12. Remove the positive crankcase ventilation (PCV) hose (with valve).
    13. Fig 9: View Of Upper Engine Wire Harness Retainer Nut
    GM899740Courtesy of GENERAL MOTORS CORP.
  13. Remove the upper engine wire harness retainer nut (1).
  14. Reposition the upper engine wire harness aside.
    15. Fig 10: View Of EVAP/Fuel Hose/Pipes
    GM856643Courtesy of GENERAL MOTORS CORP.
  15. Disconnect the fuel feed and return pipes (1) from the fuel rail. Refer to Quick Connect Fitting(s) Service (Metal Collar) .
  16. Disconnect the fuel pressure regulator vacuum line.
    17. Fig 11: View Of Fuel Rails
    GM376389Courtesy of GENERAL MOTORS CORP.
  17. Remove the fuel rail bolts.
    18. NOTE:
    • Remove the fuel rail assembly carefully in order to prevent damage to the injector electrical connector terminals and the injector spray tips. Support the fuel rail after the fuel rail is removed in order to avoid damaging the fuel rail components.
    • Cap the fittings and plug the holes when servicing the fuel system in order to prevent dirt and other contaminants from entering open pipes and passages.
    IMPORTANT: Before removal, clean the fuel rail with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. Do not soak the fuel rail in liquid cleaning solvent.
  18. Remove the fuel rail.
    19. Fig 12: View Of Fuel Injector, Clip & O-Rings
    GM351185Courtesy of GENERAL MOTORS CORP.
  19. Remove the fuel injector lower O-ring seal (4) from each injector, if necessary.
  20. Discard the O-ring seals.
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