Isuzu Cars and Trucks 1981-1991

Intake Manifold

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REMOVAL AND INSTALLATION
Carbureted Engines
  1. Drain the cooling system and disconnect the battery cables.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.


NOTE
Before removing the intake manifold, check to make certain the engine coolant is completely drained. If any water remains in the block it will flow into the cylinders when the intake manifold is removed.

  1. Remove the air cleaner assembly.
  2.  
  3. Disconnect the radiator hose from the front part of the intake manifold.
  4.  
  5. Disconnect the fuel lines, all vacuum lines and the carburetor control cable.
  6.  
  7. Disconnect the heater hoses from the rear part of the manifold and from the connector under the dashboard.
  8.  
  9. Disconnect the distributor vacuum hose and all thermo-valve wiring. Disconnect the electric choke or solenoid wires.
  10.  


NOTE
Tag all wires before disconnecting them.

  1. Disconnect the PCV hose from the rocker cover. Disconnect the EGR valve from the EGR pipe and disconnect the air injection vacuum hose from the three-way connector.
  2.  
  3. Remove the eight nuts attaching the intake manifold and lift it clear, being careful not to snag any loose lines.
  4.  



Click image to see an enlarged view

Fig. Intake manifold assembly 4-cyl. carbureted engines

To install:

  1. Check the manifold for cracks or damage. The manifold head surfaces can be checked for distortion by using a straight edge and a feeler gauge. Distortion should be no more than 0.4mm (0.0157 in.), if it is beyond the limit, the distortion has to be corrected with a surface grinder.
  2.  
  3. Clean all gasket mating surfaces with a scraper and solvent.
  4.  
  5. Replace all gaskets and torque all nuts in sequence to 25 and 1932 ft. lbs. (34 and 1943 Nm).
  6.  
  7. Connect the PCV hose to the rocker cover. Connect the EGR valve to the EGR pipe and connect the air injection vacuum hose to the three-way connector.
  8.  
  9. Connect the distributor vacuum hose and all thermo-valve wiring. Connect the electric choke or solenoid wires.
  10.  
  11. Connect the heater hoses to the rear part of the manifold and to the connector under the dashboard.
  12.  
  13. Connect the fuel lines, all vacuum lines and the carburetor control cable.
  14.  
  15. Connect the radiator hose to the front part of the intake manifold.
  16.  
  17. Install the air cleaner assembly.
  18.  
  19. Refill the cooling system, connect the battery cables and check for leaks.
  20.  

G200Z, 4ZD1, 4ZC1-T EFI Engines
  1. Relieve the fuel pressure. Disconnect the negative battery cable and remove the air cleaner assembly.
  2.  
  3. Remove the EGR pipe clamp bolt at the rear of the cylinder head.
  4.  
  5. Raise and support the vehicle safely. Remove the EGR pipe from the intake and exhaust manifolds.
  6.  
  7. Remove the EGR valve and bracket assembly from the intake manifold.
  8.  
  9. Lower the vehicle and drain the cooling system.
  10.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the upper coolant hoses from the manifold.
  2.  
  3. Disconnect the accelerator linkage, vacuum lines, electrical wiring and fuel line from the intake manifold.
  4.  
  5. Remove the intake manifold mounting nuts and remove the manifold from the cylinder head.
  6.  
  7. Remove the lower heater hose while holding the manifold away from the engine. Remove the manifold from the vehicle.
  8.  



Click image to see an enlarged view

Fig. Intake manifold and common chamber G200Z, 4ZD1 and 4ZC1-T engines

To install:

  1. Connect the lower heater hose to the manifold. Using a new gasket, install the intake manifold. Torque the bolts to 16 ft. lbs. (21 Nm).
  2.  
  3. Connect the accelerator linkage, vacuum lines, electrical wiring and fuel line to the intake manifold.
  4.  
  5. Connect the upper coolant hose to the intake manifold.
  6.  
  7. Install the EGR valve and bracket assembly to the intake manifold.
  8.  
  9. Install the EGR pipe to the intake and exhaust manifolds. Lower the vehicle.
  10.  
  11. Install the EGR pipe clamp bolt to the rear of the cylinder head.
  12.  
  13. Install the air cleaner and connect the negative battery cable.
  14.  

4ZE1 Engine
  1. Relieve the fuel pressure. Disconnect the negative battery cable and remove the air duct.
  2.  
  3. Drain the cooling system. Remove the upper coolant hoses from the manifold.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the air regulator rubber hose from the intake plenum.
  2.  
  3. Remove the EGR valve and bracket assembly from the intake manifold.
  4.  
  5. Disconnect the accelerator linkage, vacuum lines, electrical wiring and fuel line from the throttle body.
  6.  
  7. Remove the throttle body-to-plenum nuts and the throttle body.
  8.  



Click image to see an enlarged view

Fig. Exploded view of the intake manifold assembly 4ZE1 engine

  1. Remove the plenum-to-intake manifold bolts and the plenum.
  2.  
  3. Remove the intake manifold-to-cylinder head nuts and the manifold from the cylinder head.
  4.  

To install:

  1. Using a new gasket, install the intake manifold to the cylinder head.
  2.  
  3. Using a new gasket, install the plenum to the intake manifold. Torque the bolts to 14 and 1918 ft. lbs. (20 and 1925 Nm).
  4.  
  5. Using a new gasket, install the throttle body to the plenum.
  6.  
  7. Connect the accelerator linkage, vacuum lines, electrical wiring and fuel line.
  8.  
  9. Install the EGR valve and bracket assembly to the intake manifold.
  10.  
  11. Install the air regulator rubber hose to the intake plenum.
  12.  
  13. Install the upper coolant hoses to the manifold.
  14.  
  15. Install the air duct. Connect the negative battery cable. Refill the cooling system.
  16.  

4XC1-U and 4XC1-T Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Release the fuel pressure and remove the pressure regulator.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Drain the engine coolant.
  2.  
  3. Remove the Vacuum Switching Valve (VSV).
  4.  
  5. Remove the bracket and hanger.
  6.  
  7. Remove the throttle body assembly and disconnect the engine harness assembly.
  8.  
  9. Disconnect the IAC valve and remove the relief valve.
  10.  
  11. Disconnect the MAP sensor and back pressure transducer.
  12.  
  13. Remove the EGR valve and adapter.
  14.  
  15. Remove the fuel injectors with pipe.
  16.  
  17. Remove the manifold attaching bolts and manifold.
  18.  



Click image to see an enlarged view

Fig. Intake manifold assembly 4XC1-U and 4XC1-T engines

To install:

  1. Clean the gasket mating surfaces with a scraper and solvent. Do NOT damage the aluminum surfaces. Inspect the components for distortion and damage.
  2.  
  3. Using new gaskets, install the manifold attaching bolts and manifold. Torque the bolts and nuts to 17 ft. lbs. (25 Nm).
  4.  
  5. Install the fuel injectors with pipe.
  6.  
  7. Install the EGR valve and adapter.
  8.  
  9. Connect the MAP sensor and back pressure transducer.
  10.  
  11. Connect the IAC valve and install the relief valve.
  12.  
  13. Install the throttle body assembly and connect the engine harness assembly.
  14.  
  15. Install the bracket and hanger.
  16.  
  17. Install the Vacuum Switching Valve (VSV).
  18.  
  19. Refill the engine with coolant.
  20.  
  21. Install the pressure regulator.
  22.  
  23. Connect the negative (-) battery cable, start the engine and check for leaks.
  24.  

4XE1 SOHC and DOHC Engine
  1. Disconnect negative battery cable and drain cooling system. Remove the air cleaner duct hose from the common chamber.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect and tag the following vacuum lines and wiring harness:
  2.  
    1. Fast idle vacuum hose from the air duct hose.
    2.  
    3. The MAP sensor vacuum hose from the common chamber.
    4.  
    5. Disconnect the TPC valve vacuum hose from the common chamber.
    6.  
    7. Disconnect the canister vacuum hose from the common chamber.
    8.  
    9. Electronic control gas injection harness, disconnect the 2 ECM ground connectors from the bracket located on top of the common chamber. Disconnect the 2 green and black multi-pin connectors on the top of the common chamber.
    10.  
    11. Remove the MAT sensor connector.
    12.  

  3. Disconnect the accelerator cable from the throttle body and at the common chamber. Disconnect the PCV valve hose from the valve cover.
  4.  
  5. Disconnect the master vacuum hose from the master vacuum tube at the common chamber side.
  6.  
  7. Disconnect the induction valve vacuum hose from the common chamber. Disconnect the EGR valve and the throttle valve.
  8.  
  9. Remove the fuel hose clips from the common chamber. Remove the bolt and nuts retaining the common (intake) chamber to the engine. Remove the common (intake) chamber and gasket from the engine.
  10.  



Click image to see an enlarged view

Fig. Intake manifold and common chamber 4XE1 SOHC and DOHC engines

To install:

  1. Clean the gasket mating with a scraper and solvent. Be sure to use a new gasket and torque the common chamber retaining bolts and nuts to 18 ft. lbs. (25 Nm).
  2.  
  3. Install the common (intake) chamber and gasket to the engine. Install the fuel hose clips to the common chamber. Install the bolt and nuts retaining the common (intake) chamber to the engine. Torque the bolts to 17 ft. lbs. (21 Nm).
  4.  
  5. Connect the induction valve vacuum hose to the common chamber. Connect the EGR valve and the throttle valve.
  6.  
  7. Connect the master vacuum hose to the master vacuum tube at the common chamber side.
  8.  
  9. Connect the accelerator cable to the throttle body and at the common chamber. Connect the PCV valve hose to the valve cover.
  10.  
    1. Install the MAT sensor connector.
    2.  
    3. Electronic control gas injection harness, connect the 2 ECM ground connectors to the bracket located on top of the common chamber. Connect the 2 green and black multi-pin connectors on the top of the common chamber.
    4.  
    5. Connect the canister vacuum hose to the common chamber.
    6.  
    7. Connect the TPC valve vacuum hose to the common chamber.
    8.  
    9. The MAP sensor vacuum hose to the common chamber.
    10.  
    11. Fast idle vacuum hose to the air duct hose.
    12.  

  11. Connect negative battery cable and fill cooling system. Install the air cleaner duct hose to the common chamber.
  12.  

4FB1 Diesel Engine
  1. Open the hood and disconnect the battery. Remove the air cleaner assembly.
  2.  
  3. Remove the connecting hose and PCV hose.
  4.  
  5. Remove the sensing resistor assembly.
  6.  
  7. Remove the 6 screws attaching the injection pipe clips and remove the injection pipe.
  8.  
  9. Remove the 10 bolts attaching the upper dust cover and remove the upper dust cover.
  10.  
  11. Remove the 2 bolts attaching the engine hanger and remove the engine hanger.
  12.  
  13. Remove the 2 bolts attaching the stay and remove the stay. Remove the three bolts and two nuts attaching the intake manifold and lift off the manifold.
  14.  



Click image to see an enlarged view

Fig. Intake manifold 4FB1 diesel engine

To install:

  1. Clean the gasket mating surfaces with a scraper and solvent. Inspect the components for warpage, distortion and damage.
  2.  
  3. Using a new manifold gasket, install the manifold and torque the bolts to 25 and 1932 ft. lbs. (34 and 1944 Nm).
  4.  
  5. Install the 2 bolts attaching the engine hanger and hanger.
  6.  
  7. Install the 10 bolts attaching the upper dust cover and the upper dust cover.
  8.  
  9. Install the 6 screws attaching the injection pipe clips and the injection pipe.
  10.  
  11. Install the sensing resistor assembly.
  12.  
  13. Install the connecting hose and PCV hose.
  14.  
  15. Connect the battery cable, install the air cleaner assembly, start the engine and check for leaks.
  16.  

 
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