Fuel Rail: Service and Repair

Model R620 Fuel Rail Assembly:

REMOVAL
Before removal, the fuel rail assembly may be cleaned with a spray type engine cleaner, GM X-30A or equivalent, following package instructions. Do not soak fuel rails in liquid cleaning solvent.

1. Disconnect negative battery terminal.
2. Relieve fuel system pressure. (Refer to Fuel Delivery / Service and Repair.
3. Remove intake manifold plenum.
4. Remove fuel line bracket bolt and disconnect fuel lines at rail.

NOTE:
Use a back-up wrench on the fuel rail fittings to prevent them from turning.

5. Remove fuel inlet and return line O-Rings, and discard.
6. Disconnect vacuum line at pressure regulator.
7. Disconnect injector electrical connectors.
8. Remove rail retaining bolts and fuel rail assembly.

CAUTION:
Use care in removing the fuel rail assembly, to prevent damage to the injector electrical connector terminals and the injector spray tips.
Prevent dirt and other contaminants from entering open lines and passages. All fittings should be capped, and holes plugged, during servicing.

Injectors
^ Remove injector O-Ring seal from spray tip end of each injector and discard seals.
^ Before installing injectors in fuel rail, lubricate new injector O-Ring seals with engine oil then install on spray tip end of each injector.

INSTALLATION
1. Install fuel rail assembly in intake manifold. Tilt rail assembly to install injectors.
2. Install fuel rail attaching bolts and torque to 10 Nm (88 lb in)
3. Connect injector electrical connectors.
4. Connect vacuum line to pressure regulator.
5. Install new O-Rings on fuel lines.
6. Connect fuel feed and return lines and torque to 23 Nm (17 lb ft).

NOTE:
Use a back-up wrench on the fuel rail fittings to prevent them from turning.

Inspection
^ Temporarily connect negative battery terminal.
^ Turn ignition switch to the "ON" position for two seconds, then turn to the "OFF" position for ten seconds. Again turn to the "ON" position and check for fuel leaks.
^ Disconnect negative battery terminal.

7. Install intake manifold plenum.
8. Tighten fuel filler cap.
9. Connect negative battery terminal.

NOTE:
The Electronic Control Module (ECM) will need to relearn the Idle Air Control (IAC) valve pintle position following battery reconnection. This procedure allows the ECM memory to be updated and provides for a stable idle speed.

Idle Learn Procedure
1. Install Tech 1 "Scan" tool.
2. Ignition "ON" engine "OFF."
3. Select "IAC SYSTEM," then "IDLE LEARN" in the "MISC. TEST" mode.
4. Proceed with idle learn as directed by Tech 1 "Scan" tool.