Fuel Injection Fuel Rail Assembly Replacement 4.8L, 5.3L, and 6.0L Engines

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.




1. Remove the engine sight shield. Refer to Upper Intake Manifold Sight Shield Replacement in Engine Mechanical-4.8L, 5.3L, and 6.0L.
2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .
3. Before removal, if necessary, clean the fuel rail assembly with a spray type engine cleaner, use GM X-30A or equivalent. Follow the package instructions. Do not soak fuel rail assembly in any liquid cleaning solvent.



4. Disconnect the accelerator control cable and the cruise control cable from the cable bracket, if equipped.



5. Disconnect the cruise control cable engine-end fitting from the stud on the throttle lever, if equipped.



6. Disconnect the accelerator control cable and the cruise control cable from the throttle body, if equipped.



7. Remove the upper engine wire harness retainer nut.
8. Disconnect the following electrical connectors:

•	Evaporative emission (EVAP) purge valve

•	Throttle position (TP) sensor

•	Knock sensor

•	Manifold absolute pressure (MAP) sensor.

9. Reposition the upper engine wire harness aside.
10. Remove the positive crankcase ventilation (PCV) hose.
11. Remove the fuel pressure regulator vacuum hose.
12. Remove the EVAP purge tube. Refer to Evaporative Emission System Hoses/Pipes Replacement .



13. Mark the electrical connectors to their corresponding injectors to ensure correct sequential injector firing order after reassembly.

Important: When disconnecting the Multec 2 fuel injector connectors, DO NOT use pliers or other hand tools, as the connector ends may become mangled and be rendered unusable.

14. Pull the connector position assurance (CPA) (2) on the injector connector up.
15. Push the tab (1) on the injector connector in.



16. While pushing the tab (1) on the injector connector in, release the CPA (2).
17. Disconnect the fuel injector connector electrical connector.
18. Repeat steps 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.

19. Disconnect the fuel feed and return pipes (1, 2) from the fuel rail. Refer to Metal Collar Quick Connect Fitting Service .



20. Loosen the crossover tube to right fuel rail retainer screw (22).



21. Remove the fuel rail bolts.
22. Remove the fuel rail.



23. Remove and discard the fuel injector lower O-ring seals (4) from the injectors (3).

1. Lubricate the NEW fuel injector lower O-ring seals (4) with clean engine oil.
2. Install the NEW O-ring seals (4) to the end of each injector (3).



3. Remove the retaining clip attaching screw (22) and crossover pipe retainer (21) to the right hand fuel rail.
4. Remove the crossover pipe rail (25) from the right fuel rail (15).
5. Remove the crossover pipe O-ring (20).
6. Lubricate a NEW O-ring (20) with clean engine oil.
7. Install a NEW crossover pipe O-ring (20) on the crossover pipe (25).
8. Install the crossover pipe (25) into the right fuel rail (15).

Important: When installing the retaining clip attaching screw for the crossover pipe, always start the screw by hand. This will prevent consequent stripping of the threads in the fuel rail.

9. Loosely install the crossover pipe retainer (21) and retaining clip attaching screw (22) to the right fuel rail.



10. Install the fuel rail.
11. Apply a 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.

12. Install the fuel rail bolts.

Tighten

1. Tighten the bolts to 10 N·m (89 lb in).
2. Tighten the screw to 3.8 N·m (34 lb in).



13. Connect the fuel feed and return pipes (1, 2) to the fuel rail. Refer to Metal Collar Quick Connect Fitting Service .
14. Connect the fuel injector electrical connectors.

•	Install each connector onto the correct injector in order to ensure correct sequential injector firing order.

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




15. Position the upper engine wire harness in place.
16. Connect the following electrical connectors:

•	EVAP purge valve

•

TP sensor

•	Knock sensor

•	MAP sensor.

17. Install the retainer nut to the upper engine wire harness.

Tighten
Tighten the nut to 5.5 N·m (49 lb in).

18. Install the EVAP purge tube. Refer to Evaporative Emission System Hoses/Pipes Replacement .
19. Install the fuel pressure regulator vacuum hose.
20. Install the PCV hose.



21. Connect the accelerator control cable and the cruise control cable to the cable bracket, if equipped.



22. Connect the accelerator control cable to the throttle body, if equipped.



23. Connect the cruise control cable engine-end fitting to the stud on the throttle lever, if equipped.
24. 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.

25. Install the engine sight shield. Refer to Upper Intake Manifold Sight Shield Replacement in Engine Mechanical - 4.8L, 5.3L, and 6.0L.

Fuel Injection Fuel Rail Assembly Replacement 5.3L, RPO L59 (VIN Z) Engine

Important: The L59 E85 fuel rail is comprised of a material that is compatible with fuel that has a concentration of up to 85 percent Ethanol. The E85 fuel rail also uses E85 Denso fuel injectors. Because of this, special procedures will be used in servicing the fuel rail and associated components. The screws that fasten the retaining clips for the crossover pipe to the fuel rails are thread cutting and therefore should NOT be removed from the fuel rail. The fuel rail will be serviced as an entire component.

Important:  An eight-digit identification number (1) is located on the fuel rail. Refer to this model identification number if service or part replacement is required.




1. Remove the engine sight shield. Refer to Upper Intake Manifold Sight Shield Replacement in Engine Mechanical - 4.8L, 5.3L, and 6.0L.
2. Before removal, if necessary, clean the fuel rail assembly with a spray type engine cleaner, use GM X-30A or equivalent. Follow the package instructions. Do not soak fuel rail assembly in any liquid cleaning solvents.



3. Disconnect the accelerator control and cruise control cables from the cable bracket, if equipped.



4. Disconnect the cruise control cable engine-end fitting from the stud on the throttle lever, if equipped.



5. Disconnect the accelerator control cable from the throttle lever, if equipped.



6. Remove the upper engine wire harness retainer nut.
7. Disconnect the evaporative emission (EVAP) purge solenoid electrical connector.
8. Reposition the upper engine wire harness aside.
9. Relieve the fuel system pressure. Refer to Fuel Pressure Relief .



10. Mark the electrical connectors to their corresponding injectors to ensure correct sequential injector firing order after reassembly.

Important: When disconnecting the Multec® 2 fuel injector connectors, DO NOT use pliers or other hand tools, as the connector ends may become mangled and be rendered unusable.

11. Pull the connector position assurance (CPA) (2) on the injector connector up.
12. Push the tab (1) on the injector connector in.



13. While pushing the tab (1) on the injector connector in, release the CPA.
14. Disconnect the fuel injector connector electrical connector.
15. Repeat the steps 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.

16. Disconnect the fuel feed and return pipes (1, 2) from the fuel rail.
17. Disconnect the fuel pressure regulator vacuum line.



18. Remove the fuel rail bolts.
19. Remove the fuel rail.



20. Remove the fuel injector lower O-ring seal (4) from each injector, if necessary.
21. Discard the O-ring seal.

1. Lubricate the NEW fuel injector O-ring seals (4) with clean engine oil.
2. Install the NEW O-ring seals (4) onto each injector, if necessary.



3. Install the fuel rail.
4. Apply a 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 bolts.

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




6. Connect the fuel pressure regulator vacuum line.
7. Connect the fuel feed and return pipes (1, 2) to the fuel rail.
8. Connect the fuel injector electrical connectors.

•	Install each connector onto the correct fuel injector in order to ensure correct sequential injector firing order.

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




9. Position the upper engine wire harness in place.
10. Connect the EVAP purge solenoid electrical connector.
11. Install the retainer nut to the upper engine wire harness.

Tighten
Tighten the nut to 5.5 N·m (49 lb in).




12. Connect the accelerator control and cruise control cables to the cable bracket, if equipped.



13. Connect the accelerator control cable to the throttle lever, if equipped.



14. Connect the cruise control cable engine-end fitting to the stud on the throttle lever, if equipped.
15. Use the following procedure in order to inspect for leaks:

15.1.

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

15.2.

Turn OFF the ignition for 10 seconds.

15.3.

Turn ON the ignition, with the engine OFF.

15.4.

Inspect for fuel leaks.

16. Install the engine sight shield. Refer to Upper Intake Manifold Sight Shield Replacement in Engine Mechanical - 4.8L, 5.3L, and 6.0L.