Removal Procedure
Important:  An eight-digit identification   number (1) is located on the
fuel rail assembly. Refer to this       model  identification   number if
 servicing    or part replacement is required.
- Remove the engine sight
shield. Refer to 
Upper Intake Manifold Sight Shield Replacement 
  in Engine Mechanical.
 
- 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.
 
- Disconnect the accelerator
  control cable and the cruise control cable from the cable bracket.
 
- Disconnect the accelerator
  control cable and the cruise control cable from the throttle body.
 
- Remove the upper engine
  wire harness retainer nut.
 
- Disconnect the evaporative emission (EVAP) purge valve harness
connector.
 
- Reposition the upper engine wire harness aside.
 
- Relieve the fuel system pressure. Refer to
Fuel Pressure Relief 
  .
 
- Identify the connectors
  to their corresponding injectors to ensure correct sequential injector firing
          order after reassembly.
 
- 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).
 
- Push the tab (1)
on the lower side of the injector connector in order to release the connector
    from the injector.
 
- Repeat Step 12 and Step 13 for each injector connector.
 
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. | 
 
- Disconnect the fuel feed and return pipes (1, 2) from the fuel
rail.
 
- Disconnect the fuel pressure regulator vacuum line.
 
- Loosen the crossover tube
to right fuel rail retainer screw (22).
 
- Remove the fuel rail attaching
bolts.
 
- Remove the fuel rail assembly.
 
- Remove the injector lower
O-ring seal (4) from the spray tip end of each injector (3).
 
- Discard the O-ring seals.
 
Installation Procedure
- Lubricate the new lower
  injector O-ring seals (4) with clean engine oil.
 
- Install the new O-ring seals (4) on the spray tip end of
each   injector (3).
 
- Remove the crossover tube
  to the right fuel rail retainer (21).
 
- Remove the crossover tube (25) from the right fuel rail (15).
 
- Remove the O-ring (20) from the crossover tube (25).
 
- Install a new O-ring on the crossover tube.
 
- Lubricate the new O-ring with clean engine oil.
 
- Install the crossover tube (25) into the right fuel rail (15).
 
- Loosely install the crossover tube to the right fuel rail retainer (21).
 
- Install the fuel rail
  assembly to the intake manifold.
 
- Apply a 5 mm (0.020 in) band of GM P/N 12345382
  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.
- Install the fuel rail attaching bolts.
 
Tighten
- Tighten the bolts to 10 N·m (89 lb in).
 
- Tighten the right crossover pipe retainer screw to 3.8 N·m
  (34 lb in).
 
- Connect the fuel pressure
  regulator vacuum line.
 
- Connect the fuel feed and return pipes (1, 2) to
the fuel rail.
 
- 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. | 
 
- Position the upper engine
  wire harness in place.
 
- Connect the EVAP purge solenoid connector.
 
- Install the retainer nut to the upper engine wire harness.
 
Tighten
Tighten the nut to 5.5 N·m   (49 lb in).
- Connect the accelerator
control cable and the cruise control cable to the cable bracket.
 
- Connect the accelerator
control cable and the cruise control cable to the throttle body.
 
- Install the engine sight shield mounting bracket and the bolts.
Refer to 
Upper Intake Manifold Sight Shield Replacement 
in
 Engine Mechanical.
 
- Tighten the fuel filler cap.
 
- Connect the negative battery cable. Refer to 
Battery Negative Cable Disconnection and Connection 
in Engine Electrical.
 
- Use the following procedure in order to inspect for leaks:
 
| 24.1.  | Turn ON the ignition, with the engine OFF,for 2 seconds. | 
 
| 24.2.  | Turn OFF the ignition for 10 seconds. | 
 
| 24.3.  | Turn ON the ignition, with the engine OFF. | 
 
| 24.4.  | Inspect for fuel leaks. | 
 
- Install the engine sight shield. Refer to 
Upper Intake Manifold Sight Shield Replacement 
 in Engine Mechanical.