Escalade, Suburban, Tahoe, Yukon, Denali, DenaliXL, YukonXL 1999-2005

Fuel Rail (Supply Manifold) & Injectors

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Removal & Installation



4.8L, 5.3L & 6.0L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Remove the wire harness bracket nut.
  6.  
  7. Disconnect the evaporative emission (EVAP) purge solenoid electrical connector.
  8.  
  9. Disconnect the alternator electrical connector.
  10.  
  11. Disconnect the MAP and knock sensor connectors.
  12.  
  13. Remove the knock sensor harness connector from the intake manifold.
  14.  
  15. Remove the connector position assurance (CPA) lock.
  16.  
  17. Disconnect the main coil and fuel injector connectors from both sides of the engine.
  18.  
  19. Remove the harness clips from the fuel rail.
  20.  
  21. Reposition the engine wire harness aside.
  22.  
  23. Perform the following steps in order to disconnect the fuel injector electrical connectors.
    1. Mark the connectors to their corresponding injectors to ensure correct reassembly.
    2.  
    3. Pull the connector position assurance (CPA) retainer on the connector up 1 click.
    4.  
    5. Push the tab on the connector in.
    6.  
    7. Disconnect the fuel injector electrical connector.
    8.  
    9. Repeat the steps for each injector electrical connector.
    10.  

  24.  
  25. Disconnect the fuel feed pipe from the fuel rail.
  26.  
  27. Loosen the crossover tube-to-right fuel rail bolt.
  28.  
  29. Remove the fuel rail bolts.
  30.  
  31. Remove the fuel rail.
  32.  
  33. Remove the fuel injector lower O-ring seal from each injector, if necessary.
  34.  
  35. Discard the O-ring seal.

    Click image to see an enlarged view

    Fig. Fuel injector-4.8L, 5.3L and 6.0L engines



    Click image to see an enlarged view

    Fig. Fuel rail assembly-4.8L, 5.3L and 6.0L engines

  36.  
  37. Remove and discard the fuel injector retainer clip.
  38.  
  39. Remove the fuel injector.
  40.  
  41. Remove and discard the fuel injector O-ring seals. 
  42.  

To install:


NOTE
When ordering new fuel injectors, be sure to order the correct injector for the application being serviced. The fuel injector assembly is stamped with a part number identification.

  1. Lubricate the new injector O-ring seals with clean engine oil.
  2.  
  3. Install or connect the following:

    New injector O-ring seals on the injector
     
    New retainer clip on the injector
     

  4.  
  5. Push the fuel injector into the fuel rail injector socket with the electrical connector facing outward. The retainer clip locks on to a flange on the fuel rail injector socket.
  6.  
  7. Install the fuel rail.
  8.  
  9. Apply a 5 mm (0.2 in) band of threadlocker, or equivalent to the threads of the fuel rail bolts.
  10.  
  11. Install the fuel rail bolts and tighten to 89 inch lbs. (10 Nm).
  12.  
  13. Connect the fuel feed pipe to the fuel rail.
  14.  
  15. Install the PCV hose.
  16.  
  17. Perform the following steps in order to connect the fuel injector electrical connectors:
    1. Install the connectors to their corresponding injectors to ensure correct reassembly.
    2.  
    3. Connect the fuel injector electrical connector.
    4.  
    5. Push the CPA retainer on the connector in 1 click.
    6.  
    7. Repeat the steps for each injector electrical connector.
    8.  

  18.  
  19. Position the engine wire harness.
  20.  
  21. Connect the main coil and fuel injector connectors to both sides of the engine.
  22.  
  23. Install the harness clips to the fuel rail.
  24.  
  25. Install the CPA retainers.
  26.  
  27. Connect the MAP and knock sensor connectors.
  28.  
  29. Install the knock sensor harness connector to the intake manifold.
  30.  
  31. Connect the EVAP purge solenoid electrical connector.
  32.  
  33. Connect the alternator electrical connector.
  34.  
  35. Install the wire harness bracket nut.
  36.  
  37. Tighten the fuel cap.
  38.  
  39. Connect the negative battery cable.
  40.  
  41. Turn the ignition ON for 2 seconds.
  42.  
  43. Turn the ignition OFF for 10 seconds.
  44.  
  45. Turn the ignition ON .
  46.  
  47. Inspect for fuel leaks.
  48.  
  49. Install the engine sight shield. Tighten the engine sight shield bolts to 89 inch lbs. (10 Nm)
  50.  

4.8L, 5.3L, 6.0L & 6.2L Engines
  1. Relieve the fuel system pressure.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Engine sight shield bolts and bracket
     
    Accelerator control and cruise control cables from the cable bracket and throttle body
     
    Upper engine wire harness retainer nut
     
    Evaporative Emission (EVAP) purge valve harness connector
     

  4.  
  5. Position the upper engine wire harness aside
  6.  
  7. Tag the injector connectors for identification, then pull the top part of the injector connector up. Do not pull the top part of the connector past the top of the white portion.
  8.  
  9. Push the tab on the lower side of the injector connector to release the connect from the injection. Perform these steps on each injector connector.
  10.  
  11. Remove or disconnect the following:
    NOTE
    Use care in removing the fuel injectors in order to prevent damage to the electrical connector pins on the injector and to prevent damage to the nozzle. Service the fuel injector as a complete assembly only. The fuel injector is an electrical component. DO NOT immerse the fuel injector in any type of cleaner.



    Fuel feed and return pipes from the fuel rail
     
    Fuel pressure regulator vacuum line
     
    Crossover tube-to-right fuel rail retainer screw
     
    Fuel rail attaching bolts and fuel rail
     



    Click image to see an enlarged view

    Fig. Fuel injector (3), O-rings (2, 4) and retaining clip (1)-4.8L, 5.3L, 6.0L and 6.2L engines



    Click image to see an enlarged view

    Fig. Fuel rail assembly-4.8L, 5.3L, 6.0L and 6.2L engines



    Injector retainer clip. Insert the fork of a fuel injector assembly removal tool behind the injector connector between the fuel rail pod and the 3 protruding retaining clip ledges. Use a prying motion while inserting the tool in order to force the injector out of the fuel rail pod.
     
    Injector retainer clip
     
    Injector O-ring seals from both ends of the injector. Discard the O-ring seals.
     

  12.  

To install:


NOTE
When ordering new fuel injectors, be sure to order the correct injector for the application being serviced. The fuel injector assembly is stamped with a part number identification.

  1. Lubricate the new injector O-ring seals with clean engine oil.
  2.  
  3. Install or connect the following:

    New injector O-ring seals on the injector
     
    New retainer clip on the injector
     

  4.  
  5. Push the fuel injector into the fuel rail injector socket with the electrical connector facing outward. The retainer clip locks on to a flange on the fuel rail injector socket.
  6.  
  7. Remove the crossover tube-to-right fuel rail retainer, then remove the crossover tube.
  8.  
  9. Replace the crossover tube O-ring with a new, lubricated one.
  10.  
  11. Install or connect the following:

    Crossover tube and loosely install the retainer
     
    Fuel rail to the intake manifold
     
    Apply a 0.020 in. (5mm) band of threadlock to the fuel rail retaining bolts
     
    Fuel rail bolts and tighten to 89 inch lbs. (10 Nm)
     
    Crossover pipe retainer and tighten to 34 inch lbs. (3.8 Nm)
     
    Fuel pressure regulator vacuum line
     
    Fuel feed and return pipes
     
    Fuel injector electrical connectors, as tagged. Rotate the injectors as necessary to avoid stretching the wire harness.
     
    Upper engine wire harness
     
    EVAP purge solenoid electrical connector
     
    Upper engine wire harness retainer nut and tighten to 49 inch lbs. (5.5 Nm)
     
    Accelerator control and cruise control cables
     
    Engine sight shield mounting bracket and bolts
     

  12.  
  13. Tighten the fuel cap.
  14.  
  15. Connect the negative battery cable.
  16.  
  17. Turn the ignition ON for 2 seconds.
  18.  
  19. Turn the ignition OFF for 10 seconds.
  20.  
  21. Turn the ignition ON .
  22.  
  23. Inspect for fuel leaks.
  24.  
  25. Install the engine sight shield. Tighten the engine sight shield bolts to 89 inch lbs. (10 Nm).
  26.  

5.7L & 7.4L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
    NOTE
    Use care when removing the injectors to prevent damage to the electrical connector pins on the injector and the nozzle. The fuel injector is serviced as a complete assembly only. Since the injector is an electrical component, it should not be immersed in any type of cleaner.

  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Remove or disconnect the following:

    Negative battery cable
     
    Intake manifold plenum
     
    Fuel rail assembly
     
    Wiring harness
     
    Injector clip and discard it
     
    Injector O-ring seals from both ends of the injector. Save the O-ring backups for use on reassembly.

    Click image to see an enlarged view

    Fig. Exploded view of the fuel rail assembly-5.7L and 7.4L Engines



    Click image to see an enlarged view

    Fig. Exploded view of the fuel injector assembly-5.7L and 7.4L Engines

     

  6.  

To install:

  1. Install or connect the following:

    O-ring backups before installing the O-rings
     

  2.  
  3. Lubricate the new injector O-rings with clean engine oil

    O-ring to injector assembly
     
    Fuel injector into the fuel rail injector socket with the electrical connectors facing outward
     
    New injector retaining clips on the injector fuel rail assembly by sliding the clip into the injector groove as it snaps onto the fuel rail
     
    Fuel rail assembly
     
    Manifold plenum
     
    Wiring harness
     
    Negative battery cable
     

  4.  

8.1L Engine
  1. Relieve the fuel system pressure.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Engine sight shield nuts and bracket
     
    Alternator harness connector
     
    Evaporative Emission (EVAP) purge valve harness connector
     
    Throttle Position (TP) sensor electrical connector
     
    Electronic Throttle Control (ETC) electrical connector
     
    Upper engine wire harness bracket studs, and position the harness aside
     

  4.  
  5. Tag the injector connectors for identification, then pull the top part of the injector connector up. Do not pull the top part of the connector past the top of the white portion.
  6.  
  7. Push the tab on the lower side of the injector connector to release the connector from the injector. Perform these steps on each injector connector.
  8.  
  9. Remove or disconnect the following:
    NOTE
    Use care in removing the fuel injectors in order to prevent damage to the electrical connector pins on the injector and to prevent damage to the nozzle. Service the fuel injector as a complete assembly only. The fuel injector is an electrical component. DO NOT immerse the fuel injector in any type of cleaner.



    Fuel feed and return pipes from the fuel rail
     
    Fuel pressure regulator vacuum line
     
    Fuel rail attaching bolts and fuel rail
     



    Injector retainer clip. Insert the fork of a fuel injector assembly removal tool behind the injector connector between the fuel rail pod and the 3 protruding retaining clip ledges. Use a prying motion while inserting the tool in order to force the injector out of the fuel rail pod.
     
    Injector retainer clip
     
    Injector from the fuel rail pod
     
    Injector O-ring seals from both ends of the injector. Discard the O-ring seals.

    Click image to see an enlarged view

    Fig. 8.1L engine fuel rail. (1) fuel rail (2) injector (3) bolt



    Click image to see an enlarged view

    Fig. 8.1L engine fuel injector. (1) retaining clip (2) upper O-ring (3) injector (4) lower O-ring

     

  10.  

To install:


NOTE
When ordering new fuel injectors, be sure to order the correct injector for the application being serviced. The fuel injector assembly is stamped with a part number identification.

  1. Lubricate the new injector O-ring seals with clean engine oil.
  2.  
  3. Install or connect the following:

    New injector O-ring seals on the injector
     
    New retainer clip on the injector
     

  4.  
  5. Push the fuel injector into the fuel rail injector socket with the electrical connector facing outward. The retainer clip locks on to a flange on the fuel rail injector socket.
  6.  
  7. Install or connect the following:

    Fuel rail to the intake manifold
     
    Apply a 0.020 in. (5mm) band of threadlock to the fuel rail retaining bolts
     
    Fuel rail bolts and tighten to 106 inch lbs. (12 Nm)
     
    Fuel pressure regulator vacuum line
     
    Fuel feed and return pipes
     
    Fuel injector electrical connectors, as tagged. Rotate the injectors as necessary to avoid stretching the wire harness
     
    Upper engine wire harness bracket
     
    Retainer studs to the upper engine wire harness and tighten the nut to 89 inch lbs. (10 Nm)
     
    Alternator electrical connector
     
    EVAP purge solenoid electrical connector
     
    TP and ETC sensor connectors
     
    Engine sight shield mounting bracket and bolts
     

  8.  
  9. Tighten the fuel cap.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Turn the ignition ON for 2 seconds.
  14.  
  15. Turn the ignition OFF for 10 seconds.
  16.  
  17. Turn the ignition ON .
  18.  
  19. Inspect for fuel leaks.
  20.  
  21. Install the engine sight shield. Tighten the engine sight shield bolts to 89 inch lbs. (10 Nm).
  22.  

  1. Relieve the fuel system pressure.
  2.  
  3. Remove or disconnect the following:

    Negative battery cable
     
    Engine sight shield nuts and bracket
     
    Alternator harness connector
     
    Evaporative Emission (EVAP) purge valve harness connector
     
    Throttle Position (TP) sensor electrical connector
     
    Electronic Throttle Control (ETC) electrical connector
     
    Upper engine wire harness bracket studs, and position the harness aside
     

  4.  
  5. Tag the injector connectors for identification, then pull the top part of the injector connector up. Do not pull the top part of the connector past the top of the white portion.
  6.  
  7. Push the tab on the lower side of the injector connector to release the connect from the injector. Perform these steps on each injector connector.
  8.  
  9. Remove or disconnect the following:
    NOTE
    Use care in removing the fuel injectors in order to prevent damage to the electrical connector pins on the injector and to prevent damage to the nozzle. Service the fuel injector as a complete assembly only. The fuel injector is an electrical component. DO NOT immerse the fuel injector in any type of cleaner.



    Fuel feed and return pipes from the fuel rail
     
    Fuel pressure regulator vacuum line
     
    Fuel rail attaching bolts and fuel rail
     



    Injector retainer clip. Insert the fork of a fuel injector assembly removal tool behind the injector connector between the fuel rail pod and the 3 protruding retaining clip ledges. Use a prying motion while inserting the tool in order to force the injector out of the fuel rail pod.
     
    Injector retainer clip
     
    Injector from the fuel rail pod
     
    Injector O-ring seals from both ends of the injector. Discard the O-ring seals.
     

  10.  

To install:


NOTE
When ordering new fuel injectors, be sure to order the correct injector for the application being serviced. The fuel injector assembly is stamped with a part number identification.

  1. Lubricate the new injector O-ring seals with clean engine oil.
  2.  
  3. Install or connect the following:

    New injector O-ring seals on the injector
     
    New retainer clip on the injector
     

  4.  
  5. Push the fuel injector into the fuel rail injector socket with the electrical connector facing outward. The retainer clip locks on to a flange on the fuel rail injector socket.
  6.  
  7. Install or connect the following:

    Fuel rail to the intake manifold
     
    Apply a 0.020 (5mm) band of threadlock to the fuel rail retaining bolts
     
    Fuel rail bolts and tighten to 106 inch lbs. (12 Nm)
     
    Fuel pressure regulator vacuum line
     
    Fuel feed and return pipes
     
    Fuel injector electrical connectors, as tagged. Rotate the injectors as necessary to avoid stretching the wire harness
     
    Upper engine wire harness bracket
     
    Retainer studs to the upper engine wire harness and tighten the nut to 89 inch lbs. (10 Nm)
     
    Alternator electrical connector
     
    EVAP purge solenoid electrical connector
     
    TP and ETC sensor connectors
     
    Engine sight shield mounting bracket and bolts
     

  8.  
  9. Tighten the fuel cap.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Turn the ignition ON for 2 seconds.
  14.  
  15. Turn the ignition OFF for 10 seconds.
  16.  
  17. Turn the ignition ON .
  18.  
  19. Inspect for fuel leaks.
  20.  
  21. Install the engine sight shield. Tighten the engine sight shield bolts to 89 inch lbs. (10 Nm).
  22.  

 
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