GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C Sierra - 2WD 🢒 Engine 🢒 Engine Controls - 8.1L 🢒 Fuel Injection Fuel Rail Assembly Replacement

Removal Procedure

    Important:  An eight digit identification number  is located on the fuel rail assembly. Refer to this model identification number if servicing or part replacement is required.

  1. Relieve the fuel system pressure. Refer to Fuel Pressure Relief in engine controls.
  2. Before removal, clean the fuel rail assembly with a spray type engine cleaner, GM X-30A or equivalent, if necessary. Follow the package instructions. Do not soak fuel rails in liquid cleaning solvent.

    3. Object Number: 665445 Size: SH
  3. Remove the engine sight shield bracket (1) nuts and bracket.

    4. Object Number: 665449 Size: SH
  4. Disconnect the generator harness connector (1).
  5. Disconnect the (EVAP) canister purge valve harness connector (4).
  6. Disconnect the throttle position (TP) sensor harness connector (2).
  7. Disconnect the electronic throttle control (ETC) harness connector (3).
  8. Remove the upper engine wire harness bracket studs and position the upper engine wire harness aside.
  9. Remove the Secondary Air Injection (AIR) crossover pipe if applicable, Refer to Secondary Air Injection Crossover Pipe/Hose Replacement .

    10. Object Number: 372749 Size: SH
  10. Identify the connectors to their corresponding injectors to ensure correct sequential injector firing order after reassembly.
  11. Pull the top portion (2) of the injector connector up. Do not pull the top portion of the connector past the top of the white portion (1).

    12. Object Number: 372753 Size: SH
  12. Push the tab (1) on the lower side of the injector connector in order to release the connector from the injector.
  13. Repeat step 12 and step 13 for each injector connector.

    14. Object Number: 300360 Size: SH

    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.

  14. Disconnect the fuel feed and return pipes (1, 2) from the fuel rail.

    15. Object Number: 665447 Size: SH
  15. Disconnect the fuel pressure regulator vacuum line (1).

    16. Object Number: 665443 Size: SH
  16. Remove the fuel rail attaching bolts (3).
  17. Remove the fuel rail assembly (1).

    18. Object Number: 351185 Size: SH
  18. Remove the injector lower O-ring seal (4) from the spray tip end of each injector (3).
  19. Discard the O-ring seals.

Installation Procedure

    Object Number: 351185 Size: SH
  1. Lubricate the new lower injector O-ring seals (4) with clean engine oil.
  2. Install the new O-ring seals (4) on the spray tip end of each injector (3).

    3. Object Number: 665443 Size: SH
  3. Install the fuel rail assembly (1) to the intake manifold.
  4. Apply a 5 mm (0.020 in) band of GM P/N 12345382 threadlock, or equivalent, to the threads of the fuel rail bolts.

    5. 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.

  5. Install the fuel rail attaching bolts (3).

    6. Tighten
    Tighten the bolts to 12 N·m (106 lb in).


    Object Number: 665447 Size: SH
  6. Connect the fuel pressure regulator vacuum line (1).

    7. Object Number: 300360 Size: SH
  7. Connect the fuel feed and return pipes (1, 2) to the fuel rail.
  8. Connect the injector electrical connectors (4).
    9. • Install each connector on the proper injector in order to ensure correct sequential injector firing order.
    • Rotate the injectors as required in order to avoid stretching the wire harness.
  9. Install the Secondary Air Injection (AIR) crossover pipe if applicable. Refer to Secondary Air Injection Crossover Pipe/Hose Replacement .

    10. Object Number: 665449 Size: SH
  10. Install the upper engine wire harness bracket .
  11. Install the retainer studs to the upper engine wire harness.

    12. Tighten
    Tighten the nut to 10 N·m (89 lb in)


    Object Number: 665449 Size: SH
  12. Reconnect the generator harness connector (1).
  13. Reconnect the (EVAP) canister purge valve harness connector (4).
  14. Reconnect the throttle position (TP) sensor harness connector (2).
  15. Reconnect the electronic throttle control (ETC) harness connector (3).

    16. Object Number: 665445 Size: SH
  16. Install the engine sight shield mounting bracket blots and nuts.

    17. Tighten
    Tighten the bolts to 10 N·m (89 lb in)

  17. Tighten the fuel filler cap.
  18. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  19. Inspect for leaks using the following procedure:
    20. 19.1. Turn ON the ignition, with the engine OFF, for 2 seconds.
    19.2. Turn OFF the ignition for 10 seconds.
    19.3. Turn ON the ignition, with the engine OFF.
    19.4. Inspect for fuel leaks.
  20. Install the engine sight shield.

    21. Tighten
    Tighten the bolts to 10 N·m (89 lb in).