GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Tools Required

    • J 34730 Fuel Pressure Gauge
    • J 37088-A Fuel Line Quick-Connect Tools

Notice: Use care in removing the fuel injectors in order to prevent damage to the fuel injector electrical connector pins or the fuel injector nozzles. Do not immerse the fuel injector in any type of cleaner. The fuel injector is an electrical component and may be damaged by this cleaning method.

Important: The fuel injector is serviced as a complete assembly only. If the fuel injectors are found to be leaking, the engine oil may be contaminated with fuel.


    Object Number: 180378  Size: SH
  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .

  2. Object Number: 12256  Size: SH
  3. Remove the fuel rail. Refer to Fuel Injection Fuel Rail Assembly Replacement .

  4. Object Number: 12397  Size: SH
  5. Remove the fuel injector retaining clips (2).
  6. Remove the fuel injector(s) (3).
  7. Remove the fuel injector upper O-ring (1).
  8. Remove the fuel injector lower O-ring (5).
  9. Important: Fuel injector O-rings should always be replaced whenever fuel injectors are serviced.

    Each fuel injector is calibrated for a specific flow rate. Be sure to use the correct part number when ordering replacement fuel injectors.

    The fuel injector lower O-ring (5) uses a nylon collar, called the O-ring backup (4), to properly position the O-ring on the fuel injector. Be sure to reinstall the O-ring backup, or the sealing O-ring may move on the fuel injector when installing the fuel rail. If the sealing O-ring is not seated properly, a vacuum leak is possible and driveability complaints may occur.

  10. Remove the O-ring backup (4).

Installation Procedure

    Important: When ordering new fuel injectors, be sure to order the correct injector for the application being serviced.

    The upper and lower fuel injector O-rings use different part numbers. To identify the correct O-ring, the upper O-ring is black and the lower O-ring is brown. Both O-rings are the same size but consist of different material.

    The fuel injector lower O-ring uses a nylon collar, called the O-ring backup, to properly position the O-ring on the injector. Always reinstall the O-ring backup, or the sealing O-ring may move on the injector when installing the fuel rail and result in a possible vacuum leak.

    Fuel injector O-rings should always be replaced whenever fuel injectors are serviced.

  1. Coat all new O-rings with engine oil before installing

  2. Object Number: 12397  Size: SH
  3. Install the fuel injector back up O-ring (4).
  4. Install the fuel injector lower O-ring (5).
  5. Install the fuel injector upper O-ring (1).
  6. Install the fuel injector(s) to the fuel rail (3).
  7. Install the fuel injector retaining clips (2).

  8. Object Number: 12256  Size: SH
  9. Install the fuel rail. Refer to Fuel Injection Fuel Rail Assembly Replacement
  10. Connect the negative battery cable. Refer to

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

    in Cautions and Notices.
  11. Inspect for leaks.
  12. 9.1. Turn the ignition switch On for 2 seconds.
    9.2. Turn the ignition switch Off for 10 seconds.
    9.3. Turn the ignition switch On position.
    9.4. Check for fuel leaks.
  13. Install the rear seat cushion. Refer to Rear Seat Cushion Replacement .
  14. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement .