Envoy, Rainer, Trailblazer 2006-2007

Fuel Rail (Supply Manifold) & Injectors

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Removal & Installation



4.2L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Relieve the fuel system pressure. Refer to the fuel system relief procedure in this section.
  4.  
  5. Remove or disconnect the following:
    NOTE
    Clean the fuel rail assembly with a suitable spray cleaner before proceeding. Never soak the fuel rail in a cleaning solvent.



    Negative battery cable, if not done already
     
    Intake manifold
     



    Fuel pressure regulator vacuum line
     
    Fuel feed and return pipes
     
    Fuel injector in-line electrical connector
     
    Fuel rail attaching bolts and fuel rail
     
    Fuel injector harness connector from the fuel injectors
     
    Injector retaining clip
     
    Injector from the fuel rail
     
    Retainer clip and O-ring seals from each end of the injector and discard
     

  6.  

To install:


NOTE
Each injector is calibrated. When replacing the fuel injectors, be sure to replace it with the correct injector.

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

    O-rings on the injector
     
    New retainer clip on the injector
     

  4.  
  5. Push the fuel injector into the fuel rail socket, making sure the connector faces outward. The retainer clip locks to a flange on the fuel rail injector socket.

    Fuel rail assembly. Tighten the bolts to 89 inch lbs. (10 Nm).
     
    Fuel feed and return lines to the rail
     
    Fuel injector electrical connectors
     
    Fuel pressure regulator vacuum line
     
    Intake manifold
     
    Negative battery cable
     

  6.  
  7. Turn the ignition ON for 2 seconds and then turn it OFF for 10 seconds. Again turn the ignition ON and check for leaks.
  8.  

5.3L & 6.0L Engines
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Relieve the fuel system pressure. Refer to the fuel system relief procedure in this section.
  4.  
  5. Remove or disconnect the following:

    Negative battery cable, if not done already
     
    A/C compressor pressure switch electrical connector
     
    Wire harness from the clip on the cylinder head
     
    Mass Airflow/Intake Air Temperature (MAF/IAT) sensor connector
     
    Alternator electrical connector
     
    Right side electrical connectors from the coil main electrical harness, Electronic Throttle Control (ETC) and fuel injectors.
     

  6.  
  7. To detach the injector connector: Matchmark the connectors, pull the Connector Position Assurance (CPA) retainer up 1 click. Push the tab on the connector in, then detach the injector connector.
    WARNING
    Be very careful when removing the fuel rail and injectors not to damage the connector terminals or injector spray tips



    Electrical harness from the clips on the ignition coil bracket
     
    Evaporative emission (EVAP) purge solenoid electrical connector
     
    Knock Sensor (KS) electrical connector
     
    Manifold Absolute Pressure (MAP) electrical connector
     
    Main coil
     
    Fuel injector electrical connector (right side)
     
    Electrical harness from the clips on the ignition coil bracket
     
    Upper engine wire harness retainer nut. Position the wire harness aside.
     
    Fuel feed and return pipes from the rail
     
    Fuel pressure regulator vacuum line
     
    Fuel rail bolts
     
    Fuel rail, after cleaning with a spray-type cleaner
     



    Fuel injector from the fuel rail
     
    Fuel injector retainer clip and discard
     
    Fuel injector lower O-ring seals and discard

    Click image to see an enlarged view

    Fig. Exploded view of the fuel rail mounting-5.3L and 6.0L engines



    Click image to see an enlarged view

    Fig. Exploded view of the fuel injector (3), retainer (1) and O-ring seals (2, 4)-5.3L and 6.0L engines

     

  8.  

To install:

  1. Install or connect the following:

    New O-ring seals on the injectors, after lubricating with clean engine oil
     
    New retainer clip on the injector
     
    Fuel injector by pushing it into the fuel rail socket
     
    Fuel rail
     
    Apply 0.20 (5mm) band of threadlock to the threads of the fuel rail bolts
     
    Fuel rail bolts and tighten to 89 inch lbs. (10 Nm)
     
    Fuel pressure regulator vacuum line
     
    Fuel feel and return pipes
     
    Route the upper electrical harness into position over the engine.
     
    Engine harness bracket nut and tighten to 89 inch lbs. (10 Nm)
     
    PCV valve and hose
     
    EVAP purge solenoid, KS, MAP sensor, main coil & fuel injector electrical connectors
     
    Harness to the clips on the ignition coil bracket
     
    Main coil, ETC, fuel injector electrical connectors
     
    Harness to the clips on the ignition coil bracket
     
    Alternator electrical connector
     
    MAF/IAT sensor connector
     
    Wire harness to the clip on the cylinder head
     
    A/C compressor switch electrical connector
     
    Air cleaner outlet duct
     
    Fuel fill cap
     
    Negative battery cable
     

  2.  
  3. Refill the engine cooling system.
  4.  

 
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