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.
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. Remove the air cleaner assembly. Refer to Air Cleaner Assembly Replacement.
4. Disconnect the generator harness connector (1).
5. Disconnect the evaporative emission (EVAP) 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. Identify the connectors to their corresponding injectors to ensure correct sequential injector firing order after reassembly.
10. 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).



11. Push the tab (1) on the lower side of the injector connector in order to release the connector from the injector.
12. Repeat step 12 and step 13 for each injector connector.




Caution: 

•	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.

13. Disconnect the fuel feed pipes (1) from the fuel rail.



14. Disconnect the fuel pressure regulator vacuum line (1).



15. Remove the fuel rail studs.
16. Remove the fuel rail assembly.



17. Remove the injector lower O-ring seal (4) from the spray tip end of each injector (3).
18. Discard the O-ring seals.

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. Install the fuel rail assembly to the intake manifold.
4. Apply a 5 mm (0.020 in) band of GM P/N 12345382 threadlock (Canadian P/N 10953489), or equivalent, to the threads of the fuel rail bolts.

Caution: Refer to Fastener Caution in the Preface section.

5. Install the fuel rail studs.

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




6. Connect the fuel pressure regulator vacuum line (1).



7. Connect the fuel feed pipe (1) to the fuel rail.
8. Connect the injector electrical connectors.

•	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 upper engine wire harness bracket.
10. Install the retainer studs to the upper engine wire harness.

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

11. Reconnect the generator harness connector (1).
12. Reconnect the EVAP purge valve harness connector (4).
13. Reconnect the TP sensor harness connector (2).
14. Reconnect the ETC harness connector (3).
15. Tighten the fuel filler cap.
16. Connect the negative battery cable.
17. Inspect for leaks using the following procedure:

17.1.

Turn ON the ignition, with the engine OFF for 2 seconds.

17.2.

Turn OFF the ignition for 10 seconds.

17.3.

Turn ON the ignition, with the engine OFF.

17.4.

Inspect for fuel leaks.

18. Install the air cleaner assembly. Refer to Air Cleaner Assembly Replacement.