An eight digit identification number (1) is stamped on the fuel rail assembly. Refer to this model identification number if servicing or part replacement is required.

The nine digit number stamped on the fuel rail assembly indicates the day (2) and year (3) that the fuel rail was built, the plant code (4), the shift ID (5), and the source code (6).

Notice: 

•	Use care when removing the fuel rail assembly in order to prevent damage to the injector electrical connector terminals and the injector spray tips. When the fuel rail is removed, support the fuel rail in order to avoid damaging the fuel rail components.

•	Cap the fittings and plug the holes when servicing in order to prevent dirt and other contaminants from entering open pipes and passages.

•	The upper and lower O-rings are different colors (black and brown). Install the black O-ring in the upper position on the injector. Install the brown O-ring in the lower position on the injector. The O-rings are the same size but are made of different materials.

1. Disconnect the negative battery cable.
2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief.
3. 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.
4. Disconnect the quick-connect fittings from the fuel rail. Refer to Metal Collar Quick Connect Fitting Service or Plastic Collar Quick Connect Fitting Service.
5. Disconnect the vacuum line from the fuel pressure regulator.
6. Disconnect the electrical harness from the routing clips on the fuel rail.
7. Disconnect the electrical connectors from the fuel injectors. Identify the connectors to their corresponding injectors to ensure correct injector firing order after reassembly.
8. Remove the fuel rail attaching bolts.
9. Remove the fuel rail assembly.
10. Remove the injector lower O-ring seal from the spray tip end of each injector.
11. Discard the O-ring seals. Save the O-ring backups.

Important: 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.

1. Lubricate the new lower injector O-ring seals.
2. Install the new O-ring seals on the spray tip end of each injector.
3. Install the fuel rail assembly to the intake manifold.

Notice: Refer to Fastener Notice in the Preface section.

4. Install the fuel rail attaching bolts.

Tighten
Tighten the fuel rail attaching bolts to 10 N·m (89 lb in).

5. Install the injector electrical connectors.

•	Install each connector on the proper injector to ensure correct sequential injector firing order.

•	Rotate the injectors as required in order to avoid stretching the wire harness.

6. Install the electrical harness into the routing clips on the fuel rail.
7. Connect the vacuum line to the fuel pressure regulator.
8. Connect the quick-connect fittings to the fuel rail fuel pipes. Refer to Metal Collar Quick Connect Fitting Service or Plastic Collar Quick Connect Fitting Service.
9. Connect the negative battery cable.
10. Inspect for leaks by performing the following:

10.1.

Ignition ON for 2 seconds.

10.2.

Ignition OFF for 10 seconds.

10.3.

Ignition ON, inspect for fuel leaks.