Infinity_FX35_FX45_2003-2005

Intake Manifold

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Removal & Installation



3.5L Engine
Upper Intake Manifold


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Fig. Exploded view of the upper and lower halves of the upper intake manifold-3.5L engine



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Fig. Throttle body mounting bolt tightening sequence-3.5L engine



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Fig. Tightening sequence for the upper half of the upper intake manifold-3.5L engine



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Fig. Tightening sequence for the lower half of the upper intake manifold-3.5L engine



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Fig. Upper intake manifold gasket positioning-3.5L engine

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  

The upper intake manifold is constructed of two halves: upper intake manifold collector and lower intake manifold collector. Together these two components create the upper intake manifold. The 3.5L engine also uses a lower intake manifold plenum.


WARNING
To avoid the danger of being scalded, never drain engine coolant when engine is hot.


NOTE
The gasket for the intake manifold collector (upper) is secured together with the mounting bolt for the intake manifold collector (lower). Thus, even when only the gasket for upper side is replaced, the gasket for lower side must also be replaced.

  1. Remove the engine cover.
  2.  
  3. Disconnect and plug the water hoses from intake manifold collector (upper).
    CAUTION
    Do not spill engine coolant on the drive belts.

  4.  
  5. Remove the air cleaner case and air duct, as follows:
    1. Remove the air duct (inlet).
    2.  
    3. Disconnect the mass air flow sensor wiring harness connector.
    4.  
    5. Remove the air cleaner case/mass air flow sensor assembly and the air duct/resonator assembly disconnecting their joints.
      NOTE
      Add marks as necessary for easier installation.

    6.  
    7. Remove the mass air flow sensor from air cleaner case.
      CAUTION
      Handle the mass air flow sensor with care. Do not expose it to harsh vibration or shock. Do not disassemble it or touch its sensor.

    8.  
    9. Remove the resonator in the fender, lifting the left fender protector.
    10.  

  6.  
  7. Remove the electric throttle control actuator, as follows:
    1. Disconnect the wiring harness connector.
    2.  
    3. Loosen the bolts in the reverse order as shown in the figure.
      CAUTION
      Handle carefully to avoid any shock to electric throttle control actuator. Do not disassemble.

    4.  

  8.  
  9. Remove the fuel sub-tube mounting bolt to disconnect it from the rear of the intake manifold collector (lower). Refer to the fuel injector removal and installation procedure.
  10.  
  11. Disconnect the vacuum hose and water hose from the intake manifold collector (upper).
  12.  
  13. Disconnect the EVAP canister purge volume control solenoid valve bracket mounting bolt from the intake manifold collector (upper).
  14.  
  15. Loosen the bolts in the reverse order of the illustration to remove the intake manifold collector (upper).
  16.  
  17. Remove the PCV hose (between the intake manifold collector and the right-hand rocker cover).
  18.  
  19. Loosen the bolts in the reverse order of the illustration, and remove the intake manifold collector cover, gasket, intake manifold collector (lower) and gasket.
    CAUTION
    Cover all engine openings to avoid entry of foreign materials.

  20.  
  21. Check the surface distortion of both the intake manifold collector (upper and lower) mating surfaces with a straightedge and feeler gauge. If it exceeds 0.004 in. (0.1mm), replace the intake manifold collector (upper and/or lower).
  22.  

To install:

  1. Install the intake manifold collector (lower). Tighten the mounting bolts in numerical order as shown in the figure.
    NOTE
    Tighten mounting bolts to secure gasket (lower), intake manifold collector (lower), gasket (upper), and intake manifold collector cover.

  2.  
  3. Reconnect the PCV hose (between the intake manifold collector and the right-hand rocker cover).
  4.  
  5. Install the lower manifold. If the stud bolts were removed, install them and tighten them to the specified torque.
    NOTE
    The shank length from under the bolt head varies with bolt location. Install the bolts while referring to the numbers shown below and in the figure. (The bolt length does not include pilot portion.) Make sure to tighten them in numerical order as shown in the figure.



    M6 bolt (length -25mm): Positions 7, 8, 10, 11, 13, 14, 15, 16, and 18
     
    M6 bolt (length -45mm): Positions 2, 4, 5
     
    M6 bolt (length -60mm): Positions 1, 3, 6, and 9
     
    M6 nut: Positions 12, 17
     

  6.  
  7. Reattach the EVAP canister purge volume control solenoid valve bracket to the intake manifold collector (upper).
  8.  
  9. Reattach the vacuum hose and water hose to the intake manifold collector (upper).
  10.  
  11. Reattach the fuel sub-tube to the rear of the intake manifold collector (lower).
    CAUTION
    Handle carefully to avoid any shock to electric throttle control actuator.

  12.  
  13. Install the electric throttle control actuator.
    CAUTION
    Handle the mass air flow sensor with care. Do not expose it to harsh vibration or shock. Do not disassemble it or touch its sensor.

  14.  
  15. Install the mass air flow sensor in the air cleaner case.
  16.  
  17. Install the air cleaner case and air duct.
  18.  
  19. Reconnect the hoses to the intake manifold collector (upper).
  20.  
  21. Install the engine cover.
  22.  

Lower Intake Manifold


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Fig. Exploded view of the lower intake manifold-3.5L engine



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Fig. Lower intake manifold mounting bolt tightening sequence-3.5L engine

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Release the fuel pressure.
  4.  
  5. Remove the intake manifold collector (upper) and (lower).
  6.  
  7. Remove the fuel tube and fuel injector assembly.
  8.  
  9. Loosen the mounting bolts and nuts in the reverse order of the illustration to remove the lower intake manifold.
  10.  
  11. Remove the intake manifold gaskets.
    CAUTION
    Cover all engine openings to avoid entry of foreign materials.

  12.  
  13. Check the surface distortion of the intake manifold mating surface with a straightedge and feeler gauge. If it exceeds the limit of 0.04 in. (0.1mm), replace the lower intake manifold.
  14.  

To install:

  1. Install new lower intake manifold gaskets.
  2.  
  3. Install the lower intake manifold. If the stud bolts were removed, install them and tighten to 8 ft. lbs. (11 Nm). Tighten all mounting bolts and nuts to the specified torque in two or more steps in numerical order shown in the figure, as follows:
    1. Step 1: 60 inch lbs. (7 Nm)
    2.  
    3. Step 2: 21 ft. lbs. (29 Nm)
    4.  

  4.  
  5. The remainder of installation is the reverse of removal.
  6.  

4.5L Engine


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Fig. Exploded view of the intake manifold mounting and related components-2003 - 05 4.5L engine



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Fig. Exploded view of the intake manifold-2006 4.5L engine



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Fig. Tightening sequence for the upper half of the intake manifold mounting bolts-4.5L engine



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Fig. Tightening sequence for the lower half of the intake manifold mounting bolts-4.5L engine

  1. Before servicing the vehicle, refer to the Precautions Section.
    WARNING
    To avoid the danger of being scalded, never drain the engine coolant when the engine is hot.

  2.  
  3. Remove the engine cover.
  4.  
  5. Release the fuel pressure.
  6.  
  7. Drain the engine coolant.
  8.  
  9. Remove the air duct (inlet), air cleaner case and mass air flow sensor assembly, air duct and resonator assembly.
  10.  
  11. Disconnect the fuel feed hose quick connector on the engine side, the fuel damper and fuel hose assembly. Refer to the fuel injector removal and installation procedure.
    CAUTION
    While hoses are disconnected, plug them to prevent fuel from draining. Do not separate fuel damper and fuel hose.

  12.  
  13. Remove or disconnect the wiring harnesses, brackets, vacuum hose, vacuum gallery and PCV hose and tube from the intake manifold (upper).
  14.  
  15. Remove the electric throttle control actuator as follows:
    1. Disconnect the wiring harness connector.
    2.  
    3. Loosen the mounting bolts diagonally.
      CAUTION
      Handle carefully to avoid any shock to the electric throttle control actuator. Do not disassemble the electric throttle control actuator.

    4.  

  16.  
  17. Disconnect the water hoses from the water gallery.
  18.  
  19. Remove the intake manifold adaptor and water gallery.
  20.  
  21. Loosen the bolts in the reverse order as shown in the figure to remove the intake manifold (upper).
  22.  
  23. Remove the vacuum tank from the intake manifold (lower).
  24.  
  25. Remove the fuel injector and fuel tube assembly. Refer to the fuel injector removal and installation procedure.
  26.  
  27. Loosen the bolts in the reverse order as shown in the figure to remove the intake manifold (lower).
  28.  
  29. Remove the intake manifold gaskets.
    CAUTION
    Cover all engine openings to avoid entry of foreign materials.

  30.  
  31. Check the surface distortion of both the intake manifold (upper and lower) mating surfaces with a straightedge and feeler gauge. If it exceeds the limit of 0.004 in (0.1mm), replace the intake manifolds (lower and/or upper).
  32.  

To install:

  1. Install new intake manifold gaskets.
  2.  
  3. Install the intake manifold and tighten the mounting bolts in numerical order as shown in the figure. There are two types of mounting bolts. Refer to the following for locating bolts:

    M8 bolts (length -90mm): Positions 7, 8
     
    M8 bolts (length -35mm): Positions except 7 and 8
     

  4.  
  5. Install the fuel injector and fuel tube assembly.
  6.  
  7. Install the vacuum tank onto the intake manifold (lower).
  8.  
  9. Install the intake manifold (upper). Tighten the mounting bolts in the numerical order shown in the figure. There are two types of mounting bolts. Refer to the following for locating bolts:

    M8 bolts (length -80mm): Positions 4, 5, 6, and 7
     
    M8 bolts (length -25mm): Positions except 4, 5, 6, and 7
     

  10.  
  11. Install the intake manifold adaptor and water gallery.
  12.  
  13. Connect the water hoses to the water gallery.
    CAUTION
    Handle carefully to avoid any shock to the electric throttle control actuator.

  14.  
  15. Install the electric throttle control actuator. Install the intake manifold adapter gasket and electric throttle control actuator gasket so that the three protrusions for installation do not face downward.
  16.  
  17. Tighten the mounting bolts of the electric throttle control actuator equally and diagonally in several steps.
  18.  
  19. Reconnect the wiring harnesses, brackets, vacuum hose, vacuum gallery and PCV hose and tube to the intake manifold (upper).
  20.  
  21. Connect the fuel feed hose quick connector on the engine side, the fuel damper and fuel hose assembly.
  22.  
  23. Install the air duct (inlet), air cleaner case and mass air flow sensor assembly, air duct and resonator assembly.
  24.  
  25. Fill the engine cooling system with engine coolant.
  26.  
  27. Install the engine cover.
  28.  
  29. Perform the following drivability adjustments:
  30.  
  31. Perform the Throttle Valve Closed Position Learning procedure (below) when the wiring harness connector of the electric throttle control actuator is disconnected, or perform the Idle Air Volume Learning and Throttle Valve Closed Position Learning procedures (below) when the electric throttle control actuator is replaced.
  32.  

Throttle Valve Closed Position Learning
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  

The Throttle Valve Closed Position Learning procedure is an operation for the ECM to relearn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time the wiring harness connector of the electric throttle control actuator or ECM is disconnected.

  1. Make sure that accelerator pedal is fully released.
  2.  
  3. Turn ignition switch ON.
  4.  
  5. Turn ignition switch OFF wait at least 10 seconds. Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.
  6.  

Idle Air Volume Learning
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  

Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific range. It must be performed under any of the following conditions:



Each time the electric throttle control actuator or ECM is replaced.
 
Idle speed or ignition timing is out of specification.
 

Before performing the Idle Air Volume Learning procedure, make sure that all of the following conditions are satisfied. Learning will be cancelled if any of the following conditions are missed for even a moment.



Battery voltage: More than 12.9V (At idle)
 
Engine coolant temperature: 70 - 100-C (158 - 212-F)
 
PNP switch: ON
 
Electric load switch: OFF (air conditioner, headlamp, and rear window defogger)
 


NOTE
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine is started, the headlamp will not be illuminated.



Steering wheel: Neutral (Straight-ahead position)
 
Vehicle speed: Stopped
 
Transmission: Warmed-up
 
For models with CONSULT-II, drive vehicle until FLUID TEMP SE in DATA MONITOR mode of A/T system indicates less than 0.9V.
 
For models without CONSULT-II, drive vehicle for 10 minutes.
 

  1. If using the CONSULT-II tool, perform the following:
    1. Perform the "Accelerator Pedal Released Position Learning" procedure.
    2.  
    3. Perform the "Throttle Valve Closed Position Learning" procedure.
    4.  
    5. Start the engine and warm it up to normal operating temperature.
    6.  
    7. Check that all items listed above are properly set.
    8.  
    9. Select IDLE AIR VOL LEARN in WORK SUPPORT mode.
    10.  
    11. Touch START and wait 20 seconds.
    12.  
    13. Make sure that CMPLT is displayed on CONSULT-II screen. If CMPLT is not displayed, the Idle Air Volume Learning procedure will not be carried out successfully.
    14.  
    15. Rev up the engine two or three times and make sure that idle speed and ignition timing are within specifications.
    16.  

  2.  
  3. If NOT using the CONSULT-II tool, perform the following:
    NOTE
    It is best to keep track of time accurately with a clock.


    NOTE
    It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit has a malfunction.

    1. Perform the "Accelerator Pedal Released Position Learning" procedure.
    2.  
    3. Perform the "Throttle Valve Closed Position Learning" procedure.
    4.  
    5. Start the engine and warm it up to normal operating temperature.
    6.  
    7. Check that all items listed above are properly set.
    8.  
    9. Turn the ignition switch OFF and wait at least 10 seconds.
    10.  
    11. Confirm that the accelerator pedal is fully released, turn the ignition switch ON and wait 3 seconds.
      NOTE
      Repeat the following two steps quickly five times within 5 seconds.

    12.  
    13. Fully depress the accelerator pedal.
    14.  
    15. Fully release the accelerator pedal.
    16.  
    17. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops blinking and remains ON.
    18.  
    19. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
    20.  
    21. Start the engine and let it idle.
    22.  
    23. Wait 20 seconds.
    24.  
    25. Rev up the engine two or three times and make sure that idle speed and ignition timing are within specifications.
    26.  
    27. If idle speed and ignition timing are not within specification, the Idle Air Volume Learning procedure will not be successful.
    28.  

  4.  

Accelerator Pedal Released Position Learning
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  

The Accelerator Pedal Released Position Learning procedure is an operation for the ECM to relearn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time the wiring harness connector of the accelerator pedal position sensor or ECM is disconnected.

  1. Make sure that the accelerator pedal is fully released.
  2.  
  3. Turn the ignition switch ON and wait at least 2 seconds.
  4.  
  5. Turn the ignition switch OFF wait at least 10 seconds.
  6.  
  7. Turn the ignition switch ON and wait at least 2 seconds.
  8.  
  9. Turn the ignition switch OFF wait at least 10 seconds.
  10.  

 
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