Nissan Z - ZX 1970-1988 Repair Guide

Intake Manifold

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REMOVAL & INSTALLATION



1970-74 Models

Carburetor removal is required before the intake manifold can be removed.

  1. Remove the carburetors from the engine. Refer to the carburetor removal procedure in this section.
  2.  
  3. Unfasten the exhaust manifold heat shield.
  4.  
  5. Remove the retainer nuts securing the manifold to the engine, and remove the manifolds.
  6.  
  7. Remove all gasket material from both mating surfaces.
  8.  

It is important to replace the gasket whenever a manifold is removed. Be sure to get the correct replacement gasket for your vehicle. The 1970-74 models have round ports. Later models gaskets are not interchangeable.

  1. To install, reverse the removal procedure. Use new gaskets to attach the intake manifold and carburetors to the intake manifold.
  2.  

1975-83 Models

It is important to replace the gasket whenever a manifold is removed. Be sure to get the correct replacement gasket for your vehicle. The 1976-78 have round exhaust ports. The 1979-83 models have square exhaust ports. These gaskets are not interchangeable.

  1. Relieve the fuel system pressure. Refer to the procedure in Fuel System of this repair guide.
  2.  
  3. Drain the coolant from the engine.
  4.  


CAUTION
When draining 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 quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Disconnect the air regulator hose which attach between the rocker cover and intake manifold.
  2.  
  3. Tag all wire connectors around the intake manifold, then remove the cold start valve, EGR valve and throttle chamber together with the Boost Controlled Deceleration Device (BCDD).
  4.  
  5. Tag then disconnect the fuel pipe, pressure regulator, injector canister, control vacuum tube and canister purge hoses.
  6.  
  7. Remove the Positive Crankcase Ventilation (PCV) valve hose, EGR tube and small heat shield plate.
  8.  
  9. Remove the intake manifold retainer bolts, in order, and remove the manifold and heat shield as an assembly.
  10.  
  11. Clean all gasket material from both mating surfaces.
  12.  
  13. To install, reverse the removal procedures. Use new gaskets where needed. Tighten the manifold-to-engine bolts to 25-33 ft. lbs. (32-43 Nm) for 10mm bolts, or 11-18 ft. lbs. (14-23 Nm) for 8mm bolts and the manifold-to-engine nuts to 9-12 ft. lbs. (12-20 Nm).
  14.  

When torquing the manifold bolts, work from the center outwards, in two progressive steps, to the proper torque.

  1. Make sure all connections are secure before starting the vehicle.
  2.  

1984-88 Models
COLLECTOR/UPPER MANIFOLD

See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 and 15

  1. Start the engine, remove the rear floor mat and disconnect the fuel pump electrical connector. After the engine has stalled, crank the engine 2-3 times, then turn OFF the ignition switch and reconnect the fuel pump electrical connector.
  2.  
  3. Disconnect the negative battery cable. Drain the cooling system.
  4.  



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Fig. Fig. 1: Loosen the accelerator and cruise control cable nuts, then lift the cables out of the bracket



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Fig. Fig. 2: Unfasten the cables from the throttle body



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Fig. Fig. 3: Remove the cable bracket from the throttle body



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Fig. Fig. 4: Remove the retainer clamps securing the wire harness(es) to the intake manifold



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Fig. Fig. 5: Tag and unfasten any harness(es) unable to be moved out of the way



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Fig. Fig. 6: Tag and unfasten the ground wires attached to the intake manifold



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Fig. Fig. 7: Remove the hose clamps securing the intake hoses to the throttle body and air cleaner assembly



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Fig. Fig. 8: With all the clamps unfastened, remove the intake tube



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Fig. Fig. 9: Remove the screws securing the nameplate on top of the collector/upper manifold



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Fig. Fig. 10: Using a suitable Allen wrench, extension and ratchet, remove the collector/manifold retaining bolts



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Fig. Fig. 11: There is one retaining bolt on each side of the intake chamber



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Fig. Fig. 12: Remove the harness from the auxiliary air inlet valve



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Fig. Fig. 13: Remove the hose attached to the lower portion of the intake manifold



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Fig. Fig. 14: Lift the collector/upper manifold up and away from the engine



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Fig. Fig. 15: With each chamber protected from debris falling in, clean all gasket material from the mating surfaces


CAUTION
When draining 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 quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Mark and tag any wire, hose or harness attached to the collector/manifold assembly. This include the auxiliary regulator plug, ground wires and intake breather hose.
  2.  
  3. Disconnect the accelerator linkage from the throttle body.
  4.  
  5. Remove the collector/manifold cover screws and lift the plate off to access the Allen bolts securing the collector/upper manifold to the lower manifold.
  6.  
  7. Remove the collector/manifold Allen retainer bolts.
  8.  
  9. Carefully lift the collector/upper manifold off the lower manifold, and place aside.
  10.  
  11. Clean all gasket material from both mating surfaces.
  12.  
  13. To install, use new gaskets and reverse the removal procedures. Refill the cooling system.
  14.  

LOWER MANIFOLD

See Figures 16, 17, 18, 19, 20, 21, 22 and 23

  1. Remove the collector/upper manifold from the engine.
  2.  
  3. Disconnect the fuel line from the fuel filter to the fuel injector assembly.
  4.  
  5. Remove the intake manifold-to-engine bolts, referring to the illustration for the correct order, then lift out the intake manifold with the fuel injector lines attached.
  6.  



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Fig. Fig. 16: Lower Intake manifold bolt removal sequence-1984-88 models



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Fig. Fig. 17: Unfasten the clamp from the fuel filter to the fuel supply rail ...



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Fig. Fig. 18: ... and slide apart



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Fig. Fig. 19: Remove the retaining bolts securing the lower intake manifold to the block



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Fig. Fig. 20: With all the bolts removed, lift the lower intake manifold out of the engine compartment



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Fig. Fig. 21: Remove and discard the gasket between the lower intake manifold and cylinder head ...



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Fig. Fig. 22: ... as well as the seal between the lower intake manifold and thermostat housing



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Fig. Fig. 23: Lower Intake manifold torque sequence-1984-88 models

  1. Using a putty knife, clean the gasket material from both mating surfaces.
  2.  
  3. To install, use new gaskets and reverse the removal procedures. Tighten the intake manifold-to-engine nut/bolts in two or three stages in the sequence shown. Refer to the Torque Specification Chart. Refill the cooling system.
  4.  

 
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