Isuzu Ascender 2003-05

Intake Manifold

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Removal & Installation



4.2L Engine
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Disconnect the negative battery cable.
  6.  
  7. Drain the engine cooling system.
  8.  
  9. Remove or disconnect the following:

    Throttle body
     
    Powertrain Control Module (PCM)
     
    All electrical harnesses from the engine harness bracket
     
    Front differential vent hose from the bracket clip
     
    Engine harness bracket bolt and bracket
     
    Manifold Absolute Pressure (MAP) sensor connector
     
    Crankcase ventilation hose
     
    Brake hose from the booster
     
    Alternator
     
    Intake manifold bolts and manifold.
     
    Manifold gasket
     

  10.  

To install:

  1. Clean the gasket mounting surfaces. Be sure to inspect the manifold for warpage and/or cracks. If necessary, replace it.
  2.  
  3. Properly position a new intake manifold gasket.
  4.  
  5. Install or connect the following:

    Intake manifold and bolts. Torque the bolts to 16 ft. lbs. (22 Nm).
     
    Alternator
     
    Brake hose to the booster
     
    Crankcase ventilation hose, lubricating the inner diameter first with 12345884, or equivalent lubricant
     
    MAP sensor electrical connector
     
    Engine harness bracket. Tighten the retaining bolt to 37 ft. lbs. (50 Nm).
     
    Front differential vent hose to the engine harness bracket clip
     
    All harnesses to their original locations onto the engine harness bracket
     
    PCM
     
    Throttle body
     
    Negative battery cable
     

  6.  
  7. Refill the engine cooling system.
  8.  

  1. Before servicing the vehicle, refer to the precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Disconnect the negative battery cable.
  6.  
  7. Drain the engine cooling system.
  8.  
  9. Remove or disconnect the following:

    Throttle body
     
    Powertrain Control Module (PCM)
     
    All electrical harnesses from the engine harness bracket
     
    Front differential vent hose from the bracket clip
     
    Engine harness bracket bolt and bracket
     
    Manifold Absolute Pressure (MAP) sensor connector
     
    Crankcase ventilation hose
     
    Brake hose from the booster
     
    Alternator
     
    Intake manifold bolts and manifold.
     
    Manifold gasket
     

  10.  

To install:

  1. Clean the gasket mounting surfaces. Be sure to inspect the manifold for warpage and/or cracks. If necessary, replace it.
  2.  
  3. Properly position a new intake manifold gasket.
  4.  
  5. Install or connect the following:

    Intake manifold and bolts. Torque the bolts to 16 ft. lbs. (22 Nm).
     
    Alternator
     
    Brake hose to the booster
     
    Crankcase ventilation hose, lubricating the inner diameter first with 12345884, or equivalent lubricant
     
    MAP sensor electrical connector
     
    Engine harness bracket. Tighten the retaining bolt to 37 ft. lbs. (50 Nm).
     
    Front differential vent hose to the engine harness bracket clip
     
    All harnesses to their original locations onto the engine harness bracket
     
    PCM
     
    Throttle body
     
    Negative battery cable
     

  6.  
  7. Refill the engine cooling system.
  8.  

5.3L Engine

NOTE
The intake manifold, throttle body, fuel rail and injectors can be removed as an assembly. If you are not servicing these components individually, remove the intake manifold as a complete assembly.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Disconnect the negative battery cable.
  6.  
  7. Drain the engine cooling system.
  8.  
  9. Remove or disconnect the following:

    Air cleaner outlet duct
     
    A/C compressor pressure switch electrical connector
     
    Harness clip from the cylinder head and fuel raid
     
    Mass Airflow/Intake Air Temperature sensor connector
     

  10.  
  11. Disconnect the electrical connectors from the following:
    1. Main coil
    2.  
    3. Electronic Throttle Control (ETC)
    4.  
    5. Fuel injectors. 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.
    6.  



    Alternator connector
     
    Evaporative emission (EVAP) purge solenoid electrical connector
     
    Knock Sensor (KS) electrical connector
     
    Main coil
     
    Fuel injector electrical connector
     
    Electrical harness clips from the fuel rail
     
    KS harness electrical connector from the intake manifold
     
    Positive Crankcase Ventilation (PCV) valve hose and valve
     
    Heater water shutoff valve actuator inlet hose from the intake manifold
     
    EVAP purge solenoid vent tube
     
    Vacuum brake booster hose from the rear of the intake manifold
     
    Upper engine wire harness retainer nut. Position the wire harness aside.
     
    Intake manifold bolts
     
    Intake manifold and gaskets. Discard the gaskets.
     

  12.  

To install:

  1. Clean the gasket mounting surfaces. Be sure to inspect the manifold for warpage and/or cracks. If necessary, replace it.
  2.  
  3. Properly position a new intake manifold gasket.
  4.  
  5. Apply a 0.20 in. (5mm) band of a suitable threadlocking material to the intake manifold bolt threads.
  6.  
  7. Install or connect the following:

    Intake manifold and bolts. Torque the bolts, in sequence to 44 inch lbs. (5 Nm), then to 89 inch lbs. (10 Nm).
     


    Click image to see an enlarged view

    Fig. Intake manifold bolt tightening sequence-5.3L engine

    Route the electrical harness into position over the engine.
     
    Engine harness bracket nut and tighten to 89 inch lbs. (10 Nm)
     
    Vacuum brake booster hose to the rear of the intake manifold
     
    EVAP purge solenoid valve
     
    Heater water shutoff valve actuator inlet hose to the intake manifold
     
    PCV valve and hose
     
    EVAP purge solenoid, KS, MAP sensor, main coil & fuel injector electrical connectors
     
    Harness clips to the fuel rail
     
    Alternator electrical connector
     
    Main coil, ETC, fuel injector electrical connectors
     
    Electrical harness clips to the fuel rail
     
    A/C compressor pressure switch electrical connector
     
    Harness clip to the cylinder head
     
    Mass Airflow/Intake Air Temperature sensor connector
     
    Air cleaner outlet duct
     
    Fuel fill cap
     
    Negative battery cable
     

  8.  
  9. Refill the engine cooling system.
  10.  


    Click image to see an enlarged view

    Fig. Make sure to use NEW intake manifold gaskets (1)-5.3L engine



    Click image to see an enlarged view

    Fig. Exploded view of the intake manifold-5.3L engine



NOTE
The intake manifold, throttle body, fuel rail and injectors can be removed as an assembly. If you are not servicing these components individually, remove the intake manifold as a complete assembly.

  1. Before servicing the vehicle, refer to the precautions section.
  2.  
  3. Properly relieve the fuel system pressure.
  4.  
  5. Disconnect the negative battery cable.
  6.  
  7. Drain the engine cooling system.
  8.  
  9. Remove or disconnect the following:

    Air cleaner outlet duct
     
    A/C compressor pressure switch electrical connector
     
    Harness clip from the cylinder head and fuel raid
     
    Mass Airflow/Intake Air Temperature sensor connector
     

  10.  
  11. Disconnect the electrical connectors from the following:
    1. Main coil
    2.  
    3. Electronic Throttle Control (ETC)
    4.  
    5. Fuel injectors. 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.

      Alternator connector
       
      Evaporative emission (EVAP) purge solenoid electrical connector
       
      Knock Sensor (KS) electrical connector
       
      Main coil
       
      Fuel injector electrical connector
       
      Electrical harness clips from the fuel rail
       
      KS harness electrical connector from the intake manifold
       
      Positive Crankcase Ventilation (PCV) valve hose and valve
       
      Heater water shutoff valve actuator inlet hose from the intake manifold
       
      EVAP purge solenoid vent tube
       
      Vacuum brake booster hose from the rear of the intake manifold
       
      Upper engine wire harness retainer nut. Position the wire harness aside.
       
      Intake manifold bolts
       
      Intake manifold and gaskets. Discard the gaskets.
       

    6.  

  12.  

To install:

  1. Clean the gasket mounting surfaces. Be sure to inspect the manifold for warpage and/or cracks. If necessary, replace it.
  2.  
  3. Properly position a new intake manifold gasket.

    Click image to see an enlarged view

    Fig. Make sure to use NEW intake manifold gaskets (1)-5.3L engine



    Click image to see an enlarged view

    Fig. Exploded view of the intake manifold-5.3L engine

  4.  
  5. Apply a 0.20 in. (5mm) band of a suitable threadlocking material to the intake manifold bolt threads.
  6.  
  7. Install or connect the following:

    Intake manifold and bolts. Torque the bolts, in sequence to 44 inch lbs. (5 Nm), then to 89 inch lbs. (10 Nm).

    Click image to see an enlarged view

    Fig. Intake manifold bolt tightening sequence-5.3L engine

     
    Route the electrical harness into position over the engine.
     
    Engine harness bracket nut and tighten to 89 inch lbs. (10 Nm).
     
    Vacuum brake booster hose to the rear of the intake manifold
     
    EVAP purge solenoid valve
     
    Heater water shutoff valve actuator inlet hose to the intake manifold
     
    PCV valve and hose
     
    EVAP purge solenoid, KS, MAP sensor, main coil & fuel injector electrical connectors
     
    Harness clips to the fuel rail
     
    Alternator electrical connector
     
    Main coil, ETC, fuel injector electrical connectors
     
    Electrical harness clips to the fuel rail
     
    A/C compressor pressure switch electrical connector
     
    Harness clip to the cylinder head
     
    Mass Airflow/Intake Air Temperature sensor connector
     
    Air cleaner outlet duct
     
    Fuel fill cap
     
    Negative battery cable
     

  8.  
  9. Refill the engine cooling system.
  10.  

 
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