Quest 1995-1996

Intake Manifold

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Removal & Installation



The intake manifold is a two-piece design. It consists of an upper half, also called the plenum, and a lower half, which is bolted to the engine. The throttle body, control cables, fast idle solenoid, idle air control solenoid and emission connections are mounted to the upper intake manifold. The fuel injectors are mounted in the lower intake manifold.

3.0L Engines
Lower Manifold

Specific to:

Mercury Villager 1993-1998

Nissan Quest 1993-1998

  1. Relieve the fuel system pressure. Please refer to Fuel System, Electronic Fuel Injection, Relieving Fuel System Pressure for the procedure.
  2.  
  3. Remove the upper intake manifold (plenum) using the previous procedure.
  4.  
  5. Disconnect the six fuel injector electrical connectors.
  6.  
  7. Disconnect the right breather hose from the right valve cover.
  8.  
  9. Remove the crossover breather tube bracket bolt and the crossover breather tube from the upper engine front cover.
    CAUTION
    Observe all applicable safety precautions when working around fuel. Whenever servicing the fuel system, always work in a well ventilated area. Do not allow fuel spray or vapors to come in contact with a spark or open flame. Keep a dry chemical fire extinguisher near the work area. Always keep fuel in a container specifically designed for fuel storage; also, always properly seal fuel containers to avoid the possibility of fire or explosion.

  10.  
  11. Remove the four fuel injection fuel rail bolts, then position the fuel rail and the insulators out of the way.
  12.  
  13. Disconnect the engine coolant temperature (ECT) sensor electrical connector.
  14.  
  15. Disconnect the coolant temperature sending unit electrical connector.
  16.  
  17. Remove the upper radiator hose from the intake manifold water outlet. Remove the upper radiator hose bracket bolt.
  18.  
  19. Remove the bypass hose from the intake manifold water outlet.
  20.  
  21. Remove the bolt securing the water outlet to the upper engine front cover.
  22.  
  23. Remove the heater hose from the top heater core pipe.
  24.  
  25. Remove the four Allen-head lower intake manifold bolts and the four manifold nuts, in two steps. Refer to the illustration for the proper sequence.
  26.  
  27. Remove the lower intake manifold washers. Lift the lower intake manifold from the engine. Discard the gaskets.
  28.  

To install:

  1. The installation is the reverse of removal, but please note the following important steps.
  2.  
  3. Clean the lower intake manifold and cylinder head gasket surfaces. A gasket scraper and solvent may be used, however, be careful not to nick or gouge either surface.
  4.  
  5. Lay new lower intake manifold gaskets on the cylinder heads and position the lower intake manifold on the engine. Install the lower intake manifold washers, bolts, and nuts.
  6.  
  7. Tighten the lower intake manifold bolts and nuts as follows. Refer to the illustration for the proper sequence.
    1. Tighten the bolts and nuts, in sequence, to 26-43 inch lbs. (3-5 Nm).
    2.  
    3. Tighten the nuts, in sequence, to 17-20 ft. lbs. (24-27 Nm).
    4.  
    5. Tighten the bolts, in sequence, to 9-12 ft. lbs. (13-17 Nm).
    6.  
    7. Retighten the nuts to 17-20 ft. lbs. (24-27 Nm), and the bolts to 9-12 ft. lbs. (13-17 Nm), still following the tightening sequence.
    8.  

  8.  
  9. After installation, fill the cooling system. Run the engine and check for fuel, coolant, and vacuum leaks.
  10.  

Upper Manifold

Specific to:

Mercury Villager 1993-1998

Nissan Quest 1993-1998

  1. Relieve the fuel system pressure. Please refer to Fuel System, Electronic Fuel Injection, Relieving Fuel System Pressure for the procedure.
  2.  
  3. Disconnect the negative battery cable.
    CAUTION
    Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  4.  
  5. Drain the radiator and recycle the engine coolant.
  6.  
  7. Remove the air cleaner-to-intake manifold hose using the following procedure:
    1. Disconnect the breather tube, EGR solenoid vent hose, and bypass air inlet hose from the air cleaner-to-intake manifold hose.
    2.  
    3. Loosen the air cleaner-to-intake manifold hose clamps.
    4.  
    5. Disconnect the air intake resonator tube from the air cleaner-to-intake manifold hose.
    6.  
    7. Remove the air cleaner-to-intake manifold hose.
    8.  

  8.  
  9. Disconnect the two electrical connectors from the throttle body. Slide the harness from the bracket.
  10.  
  11. Remove the coolant hose from the throttle body.
  12.  
  13. Disconnect the EGR solenoid electrical connector.
  14.  
  15. Disconnect the evaporative emission (EVAP) canister vacuum hose from the intake manifold above the throttle body.
  16.  
  17. Disconnect the EVAP canister-to-throttle body hose.
  18.  
  19. On vehicles equipped with California emission controls, disconnect the manifold absolute pressure (MAP) sensor, MAP solenoid, and EVAP canister purge control solenoid electrical connectors.
  20.  
  21. Remove the fuel pressure regulator-to-upper intake manifold vacuum hose from the upper intake manifold.
  22.  
  23. Label and disconnect the spark plug wires from the spark plugs, then remove the spark plug wire boots from between the upper intake manifold runners. Remove the two spark plug wire bracket bolts and spark plug wire brackets from the upper intake manifold.
  24.  
  25. Remove the distributor dust cover. Loosen the distributor cap screws. Remove the cap from the distributor. Position the cap and plug wires aside to gain access to the main engine wiring harness.
  26.  
  27. Disconnect the rear heater valve vacuum hose from the side of the upper intake manifold, if equipped.
  28.  
  29. Remove the two wiring harness bracket bolts and remove the wiring harness bracket from the upper intake manifold and set aside.
  30.  
  31. Disconnect the speed control actuator from the throttle lever, if equipped. Disconnect the accelerator cable from the throttle lever.
  32.  
  33. Remove the speed control actuator from the hanging bracket, if equipped.
  34.  
  35. Remove the accelerator cable from the bracket attached to the top of the upper intake manifold.
  36.  
  37. Loosen the accelerator cable locknut and remove the accelerator cable from the bracket on top of the upper intake manifold.
  38.  
  39. If equipped, loosen the speed control actuator locknut, then remove the speed control actuator from the bracket on the top of the upper intake manifold and position aside.
  40.  
  41. Disconnect the brake booster hose from the power brake booster check valve.
  42.  
  43. Remove the EGR valve-to-back pressure transducer (BPT) valve tube from the EGR valve. Remove the EGR valve to manifold tube from the EGR valve.
  44.  
  45. Disconnect the fast idle control solenoid electrical connector.
  46.  
  47. Disconnect the main engine wiring harness clips from the breather tube brackets. Remove the two ground wire bolts from the upper intake manifold and position the ground wires and the harness aside.
  48.  
  49. Remove the two left breather tube bracket-to-upper intake manifold bolts. Disconnect the left breather hose from the left valve cover.
  50.  
  51. Remove the fuel tube mounting bracket bolt.
  52.  
  53. Disconnect the thermostat housing-to-upper intake manifold coolant hose.
  54.  
  55. Disconnect the EGR temperature sensor electrical connector.
  56.  
  57. Disconnect the bypass air (BPA) valve electrical connector.
  58.  
  59. Disconnect the idle air control (IAC) solenoid electrical connector.
  60.  
  61. On vehicles equipped with California emissions, disconnect the EVAP volume control valve electrical connector.
  62.  
  63. Disconnect the PCV hose from the upper intake manifold.
  64.  
  65. Remove the five Allen-head upper intake manifold-to-lower intake manifold bolts. Separate the upper intake manifold from the lower intake manifold and discard the gasket.
  66.  

To install:

  1. The installation is the reverse of removal, but please note the following important steps.
  2.  
  3. Clean the upper and lower intake manifold gasket surfaces. A gasket scraper and solvent may be used, however, be careful not to nick or gouge either surface.
  4.  
  5. Use a new gasket.
  6.  
  7. Tighten the five Allen-head upper intake manifold-to-lower intake manifold bolts to 13-16 ft. lbs. (18-22 Nm).
  8.  
  9. When installing the accelerator and cruise control cables, make the necessary adjustments.
  10.  
  11. After installation, fill the cooling system. Run the engine and check for fuel, coolant, and vacuum leaks.

    Click image to see an enlarged view

    Fig. Exploded view of upper intake manifold components-1993-98 3.0L engines

  12.  

 
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