GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 18773  Size: SH

    Notice: 

       • Remove the fuel pressure regulator in order to drain the excess fuel and in order to prevent fuel from entering the engine cylinders when the fuel injectors are removed for service. Flooded cylinders could result in engine damage.
       • Use care in removing the fuel injectors in order to prevent damage to the electrical connector pins on the injector and the nozzle. The fuel injector is serviced as a complete assembly only. Do not immerse the injector in a solvent bath.

    Notice: The following procedures must be performed in order to prevent possible engine damage from flooded cylinders.

  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure .
  2. Disconnect the negative battery cable.
  3. 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.

    Caution: Relieve the fuel system pressure before servicing fuel system components in order to reduce the risk of fire and personal injury.

    After relieving the system pressure, a small amount of fuel may be released when servicing the fuel lines or connections. In order to reduce the chance of personal injury, cover the regulator and the fuel line fittings with a shop towel before disconnecting. This will catch any fuel that may leak out. Place the towel in an approved container when the disconnection is complete.

  4. Remove the upper manifold assembly. Refer to Intake Manifold Assembly .
  5. Remove the fuel return pipe retaining bracket nut (8).
  6. Remove the fuel return pipe retaining bracket. Move the return pipe away from the regulator.
  7. Notice: 

       • Do not try to remove the fuel injectors by lifting up the fuel injector retaining bracket while the fuel injectors are still installed in the bracket slots. Improper removal may damage to the fuel injector retaining bracket and fuel injectors.
       • Remove the fuel pressure regulator before removing the bracket.

  8. Remove the pressure regulator assembly (6). Refer to Fuel Pressure Regulator Replacement .
  9. Remove the injector retainer bracket attaching screws (11).
  10. Remove the injector retainer bracket (12). Carefully slide bracket off to clear fuel injector slots and regulator.
  11. Caution: Verify that the lower (small) O-ring of each injector does not remain in the lower manifold in order to reduce the risk of fire and personal injury.

    If the O-ring is not removed with the injector, the replacement injector with new O-rings will not seat properly in the injector socket. Improper seating could cause a fuel leak.

  12. Disconnect the injector electrical connector(s).
  13. Remove the fuel injector(s) (5). Discard the O-ring seals (4).

Installation Procedure


    Object Number: 18773  Size: SH

    Important: Each fuel injector is calibrated for a specific flow rate. When replacing fuel injectors, be sure to order the correct fuel injector for the application being serviced.

  1. Lubricate the new fuel injector O-ring seals (4) with clean engine oil, and install on the fuel injector assembly (5).
  2. Install the bottom feed fuel injector assembly (5) into lower manifold fuel injector socket with the electrical connectors facing inward.
  3. Install the injector retainer bracket (12). Carefully install the bracket so that fuel injector retaining slots and the regulator are aligned with the bracket slots.
  4. Connect the injector electrical connectors.
  5. Install the pressure regulator assembly (6). Refer to Fuel Pressure Regulator Replacement .
  6. Install the injector retainer bracket attaching screws (11). Refer to Thread Locking Material.
  7. Tighten
    Tighten the injector retainer bracket attaching screws to 3.5N·m(31 lb in).

    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.

  8. Install the upper manifold assembly. Refer to Intake Manifold Assembly .
  9. Install the fuel return pipe retaining bracket.
  10. Install the accelerator cable bracket with attaching bolts/nuts.
  11. Tighten
    Tighten the accelerator cable bracket nut to 30 N·m (22 lb ft).

    Tighten the accelerator cable bracket bolts to 25 N·m (18 lb ft).

  12. Tighten the fuel filler cap.
  13. Install the air intake duct.
  14. Connect the negative battery cable.
  15. Notice: The following procedures must be performed in order to prevent possible engine damage from flooded cylinders.

  16. Check for leaking injectors. Refer to Fuel System Diagnosis .
  17. Inspect for leaks:
  18. 14.1. Turn the ignition switch ON for 2 seconds.
    14.2. Turn the ignition switch OFF for 10 seconds.
    14.3. Turn the ignition switch ON.
    14.4. Check for fuel leaks.