GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 XLR 🢒 Engine 🢒 Engine Controls and Fuel - 4.4L 🢒 Fuel Injector and Fuel Rail Replacement

Removal Procedure

    Notice: 

       • 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.

  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .
  2. Remove the front section of the supercharger inlet duct assembly. Refer to Supercharger Inlet Duct Assembly Replacement .

    3. Caution: Wear safety glasses when using compressed air in order to prevent eye injury.

  3. Clean the fuel rail and injector ports on the supercharger with compressed air.

    4. Object Number: 1613998 Size: SH
  4. Disconnect the electrical connectors from the following sensors:
    5. • The supercharger inlet absolute pressure (SCIAP) sensor (1)
    • The barometric pressure (BARO) sensor (2)
    • The manifold absolute pressure (MAP) sensor (3)
  5. Disconnect the vacuum lines from the MAP and SCIAP sensors.
  6. Remove the SCIAP, BARO and MAP sensors with the bracket.

    7. Object Number: 1614613 Size: SH

    Important: Do not allow coolant to contact the supercharger drive belt.

    Place a shop rag under the front of the supercharger to collect any remaining coolant.

  7. Partially drain the charge air cooling system. Refer to Charge Air Cooling System Draining and Filling .
  8. Remove the front section of the charge air cooler front manifold assembly (2), and discard the O-ring seals. It is not necessary to remove the hoses from the manifold pipes. Position the manifold with hoses aside to allow for removal of the fuel rail assembly. Refer to Charge Air Cooler Front Manifold Replacement .

    9. Object Number: 1645247 Size: SH
  9. Disconnect the electrical connector from the air inlet temperature 2 sensor and position aside.

    10. Object Number: 1614014 Size: SH
  10. Disconnect the supercharger bypass solenoid valve electrical connector (3) and position the harness aside.
  11. Disconnect the vacuum line from the supercharger actuator valve and position the line aside.

    12. Object Number: 1685821 Size: SH
  12. Disconnect the engine compartment fuel line fitting (1) from the fuel rail. Refer to Metal Collar Quick Connect Fitting Service .

    13. Object Number: 1614623 Size: SH
  13. Disconnect the fuel injector electrical connectors (1, 4, 6, 8) from the left and right side of the engine.

    14. Object Number: 1685827 Size: SH
  14. Remove the ground wire (1) from the right rear injector rail bolt.

    15. Object Number: 1760078 Size: SH
  15. Remove the oxygen sensor electrical connector assemblies (1,2) from the right side fuel rail brackets.

    16. Object Number: 1760081 Size: SH
  16. Remove the oxygen sensor electrical connector assemblies (1,2) from the left side fuel rail brackets.

    17. Object Number: 1685825 Size: SH
  17. Open the clip that secures the fuel rail to the front of the supercharger.
  18. Remove the fuel rail attaching studs (2).
  19. Reposition the rear inlet duct (3) as necessary, and remove the fuel rail assembly (1) from the supercharger.

    20. Object Number: 1685823 Size: SH
  20. Remove the injector lower O-ring seal from the spray tip end of each injector.
  21. Discard the O-ring seals.
  22. Remove the retainers from the fuel injectors if fuel injector removal is necessary.
  23. Remove the fuel injectors from the fuel rail.
  24. Remove the O-ring seals from the fuel injectors. Discard the O-ring seals.

Installation Procedure

    Notice: 

       • Use care when servicing the fuel system components, especially the fuel injector electrical connectors, the fuel injector tips, and the injector O-rings. Plug the inlet and the outlet ports of the fuel rail in order to prevent contamination.
       • Do not use compressed air to clean the fuel rail assembly as this may damage the fuel rail components.
       • Do not immerse the fuel rail assembly in a solvent bath in order to prevent damage to the fuel rail assembly.


    Object Number: 1685823 Size: SH
  1. If the injectors were removed from the fuel rail, lubricate the new fuel injector O-ring seals with clean engine oil.
  2. Install the new fuel injector O-ring seals on to the fuel injectors.
  3. Install the fuel injectors to the fuel rail using new retainer clips.
  4. Ensure that the injectors are aligned by orientating the electrical connectors perpendicular to the crankshaft centerline.
  5. Lubricate and install the new O-ring seals on the spray tip end of each injector.

    6. Object Number: 1685825 Size: SH
  6. Align the fuel injectors and fuel rail to the supercharger assembly.
  7. Reposition the rear inlet duct (3) as necessary, and carefully press the fuel rail assembly (1) downward until fully seated.

    8. Notice: Refer to Fastener Notice in the Preface section.

  8. Install the fuel rail attaching studs (2).

    9. Tighten
    Tighten the studs to 10 N·m (89 lb in).

  9. Install the fuel rail to the clip on the front of the supercharger.

    10. Object Number: 1760081 Size: SH
  10. Install the oxygen sensor electrical connector assemblies (1,2) to the left side fuel rail brackets.

    11. Object Number: 1760078 Size: SH
  11. Install the oxygen sensor electrical connector assemblies (1,2) to the right side fuel rail brackets.

    12. Object Number: 1685827 Size: SH
  12. Install the ground wire (1) to the right rear injector rail bolt.

    13. Object Number: 1614623 Size: SH
  13. Connect the fuel injector electrical connectors (1,4,6,8) to the left and right side of the engine.

    14. Object Number: 1685821 Size: SH
  14. Connect the engine compartment fuel line fitting (1) to the fuel rail. Refer to Metal Collar Quick Connect Fitting Service .

    15. Object Number: 1614014 Size: SH
  15. Connect the vacuum line to the supercharger actuator valve.
  16. Connect the supercharger bypass solenoid valve electrical connector (3).

    17. Object Number: 1645247 Size: SH
  17. Connect the electrical connector to the air inlet temperature 2 sensor.

    18. Object Number: 1614613 Size: SH
  18. Using NEW O-ring seals, install the front section of the charge air cooler front manifold assembly (2). Refer to Charge Air Cooler Front Manifold Replacement .

    19. Object Number: 1613998 Size: SH
  19. Install the SCIAP (1), BARO (2) and MAP (3) sensors with the bracket.
  20. Connect the vacuum lines to the MAP (3) and SCIAP (1) sensors.
  21. Connect the electrical connectors to the following sensors:
    22. • The SCIAP sensor
    • The BARO sensor
    • The MAP sensor
  22. Install the front section of the supercharger inlet duct assembly. Refer to Supercharger Inlet Duct Assembly Replacement .
  23. Install the fuel fill pipe cap.
  24. Fill the charge air cooling system with coolant. Refer to Charge Air Cooling System Draining and Filling .
  25. Check the fuel system for leaks.
  26. Install the engine sight shield. Refer to Intake Manifold Sight Shield Replacement .