GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Generic 🢒 2004 🢒 Unit Repair 🢒 Engine 🢒 Engine Controls - 2.2L (L42) 🢒 Fuel Injection Fuel Rail Assembly Replacement

Tools Required

J 45878 Combustible Gas Detector

Removal Procedure

    Caution: The Compressed Natural Gas (CNG) system operates at pressures up to 24820 kpa (3600 psi). Relieve the CNG fuel system pressure before servicing CNG fuel system components in order to reduce the risk of fire and personal injury.

  1. Relieve the CNG fuel system pressure. Refer to Fuel Pressure Relief .

    2. 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.

  2. Disconnect the negative battery cable.
  3. Remove the air cleaner outlet resonator and duct. Refer to Air Cleaner Outlet Resonator Replacement in the Engine Controls section of the J Platform Service Manual.

    4. Object Number: 945875 Size: SH
  4. Support the fuel rail flange (1) with a back-up wrench (2) while loosening the fuel hose (3) with another wrench.
  5. Remove the fuel feed hose (3) from the fuel rail (1).
  6. Disconnect the fuel rail harness connector.
  7. Remove the throttle body assembly. Refer to Throttle Body Assembly Replacement in the Engine Controls section of the J Platform Service Manual.

    8. Object Number: 945878 Size: SH
  8. Remove the CNG fuel rail mounting nuts (1).

    9. Object Number: 945882 Size: SH
  9. Grasp the CNG fuel rail from both ends and pull the rail (4) from the injector adapter plate (2).
  10. Remove the fuel rail from the vehicle.

Installation Procedure

    Object Number: 945882 Size: SH
  1. Lubricate each injector O-ring (3) with clean engine oil.
  2. Grasp the CNG fuel rail from both ends and place the rail (4) onto the mounting studs (1).
  3. Ensure that each injector (3) is located in the injector adapter plate (2) hole and push the rail into position.

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


    Object Number: 945878 Size: SH
  4. Install the CNG fuel rail mounting nuts (1).

    5. Tighten
    Tighten the nuts to 10 N·m (7 lb ft).


    Object Number: 945875 Size: SH
  5. Loosely install the fuel feed hose (3) to the fuel rail (1).
  6. Support the fuel rail flange (1) with a back-up wrench (2) while tightening the fuel hose (3) with a torque wrench and crowfoot.

    7. Tighten
    Tighten the fuel line fitting to 80 N·m (59 lb ft).

  7. Install the throttle body assembly. Refer to Throttle Body Assembly Replacement in the Engine Controls section of the J Platform Service Manual.
  8. Connect the fuel rail harness connector.

    9. 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.

  9. Connect the negative battery cable.

    10. Tighten
    Tighten the bolt to 15 N·m (11 lb ft).

  10. Install the air cleaner outlet resonator and duct. Refer to Air Cleaner Outlet Resonator Replacement in the Engine Controls section of the J Platform Service Manual.
  11. Start the engine. Inspect for CNG fuel leaks at each serviced fitting using the J 45878 .