GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

An eight digit identification number is stamped on the left hand fuel rail (fueling even cylinders 2,4,6), Refer to this number if servicing or part replacement is required).

Caution: In order to reduce the risk of fire and personal injury that may result from a fuel leak, always install the fuel injector O-rings in the proper position. If the upper and lower O-rings are different colors (black and brown), be sure to install the black O-ring in the upper position and the brown O-ring in the lower position on the fuel injector. The O-rings are the same size but are made of different materials.

Important: Important when servicing the fuel rail assembly, precautions must be taken to prevent dirt and other contaminants from entering the fuel passages. It is recommended that the fittings be capped, and the holes be plugged during servicing.


    Object Number: 22505  Size: SH
  1. Relieve fuel system pressure. Refer to Fuel Pressure Relief .
  2. Remove the upper intake manifold. Refer to Intake Manifold Replacement .
  3. Disconnect the engine fuel feed pipe at fuel rail.

  4. Object Number: 22507  Size: SH
  5. Disconnect the engine fuel return pipe at the fuel pressure regulator.
  6. Remove the fuel feed pipe and fuel return pipe O-rings and discard.

  7. Object Number: 203794  Size: SH
  8. Disconnect the main injector harness electrical connector.

  9. Object Number: 15986  Size: SH
  10. Disconnect the coolant temperature sensor electrical connector.

  11. Object Number: 21159  Size: SH
  12. Remove the fuel rail retaining bolts.
  13. Remove the fuel rail assembly.

  14. Object Number: 203802  Size: SH
  15. Disconnect the injector electrical connectors.
  16. Remove the injector electrical harness from the fuel rail.
  17. Remove the injector O-ring seal from spray tip end of each injector. Discard seals. With the O-ring removed, the O-ring backup may slip off of the injector. Be sure to retain the O-ring backup for reuse.

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: 203802  Size: SH
  1. Reinstall the injector electrical harness to the fuel rail.
  2. Connect the injector electrical connectors.
  3. Ensure that O-ring backups are on injectors before installing new O-rings. Lubricate new injector O-ring seals with clean engine oil and install on spray tip end of each injector.

  4. Object Number: 21159  Size: SH
  5. Reinstall The fuel rail assembly into the intake manifold. Tilt rail assembly to install injectors.
  6. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  7. Reinstall the fuel rail attaching bolts.
  8. Tighten
    Tighten the fuel rail attaching bolt to 10 N·m (7 lb ft).


    Object Number: 15986  Size: SH
  9. Connect the coolant temperature sensor electrical connector.

  10. Object Number: 203794  Size: SH
  11. Connect the main injector harness electrical connector.
  12. Reinstall the new O-rings on fuel feed pipe and fuel return pipe.

  13. Object Number: 22505  Size: SH
  14. Reinstall the fuel feed pipe at the fuel rail.
  15. Tighten
    Tighten the engine fuel pipe nut to 17 N·m (13  lb ft).


    Object Number: 22507  Size: SH
  16. Connect the fuel return pipe at the fuel pressure regulator.
  17. Tighten
    Tighten the engine fuel pipe nut to 17 N·m (13 lb ft).

  18. Reinstall the upper intake manifold. Refer to Intake Manifold Replacement .
  19. Tighten the fuel filler cap.
  20. Reconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in engine electrical.
  21. Check for fuel leaks.
  22. 14.1. Turn the ignition switch ON for 2 seconds.
    14.2. Then the ignition switch OFF for 10 seconds.
    14.3. Turn the ignition switch ON.
    14.4. Check for fuel leaks.