Note the location of the fuel rail ground strap (557).

1. Relieve the fuel system pressure. Refer to the 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.

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.

3. Disconnect the fuel feed hose from the fuel rail.



4. Disconnect the electrical connectors from the fuel injectors. Identify the connectors to their corresponding injectors to ensure correct sequential injector firing order after reassembly.
5. Disconnect the electrical harness from the fuel rail brackets.
6. Remove the fuel rail attaching bolts (511, 512), ground strap (557).
7. Lift evenly on both sides of the fuel rail , and remove the fuel rail assembly.
8. Remove the injector lower O-ring seal from the spray tip end of each injector.
9. Discard the O-ring seals.

1. Lubricate the new lower injector O-ring seals with clean engine oil.
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.
4. Apply a 0.5 mm (0.020 in) band of GM P/N 12345382 (Canadian P/N 10953489) threadlock or equivalent to the threads of the fuel rail bolts.

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 (511, 512), ground strap (557).

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

6. 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.

7. Connect the electrical harness to the fuel rail brackets.
8. Connect the fuel feed hose to the fuel rail fuel pipe.
9. Connect the negative battery cable.
10. Inspect for leaks.

10.1.

Turn ON the ignition for 2 seconds.

10.2.

Turn OFF the ignition for 10 seconds.

10.3.

Turn ON the ignition.

10.4.

Inspect for fuel leaks.