Mazda 323/626/929/GLC/MX-6/RX-7 1978-1989

Intake Manifold

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REMOVAL & INSTALLATION



Carbureted and Diesel Engines

See Figures 1, 2 and 3

  1. Drain the cooling system and remove the air cleaner assembly. Remove the oil dipstick.
  2.  
  3. Disconnect the following:

    Throttle and choke linkage
     
    Fuel line(s)
     
    PCV valve hose
     
    Fuel and fuel pump hoses
     
    Heater hoses
     
    Distributor vacuum line
     
    Ventilation valve hose (at the manifold)
     
    Air pump hose at the anti-afterburn valve
     
    Brake vacuum hose
     
    Canister hoses
     
    Engine harness connectors
     
    Spark plug wires
     

  4.  
  5. Remove the following components as required to gain access to the intake manifold:

    Distributor
     
    Spark plugs
     
    Carburetor secondary air pipe manifold assembly
     
    Front engine hanger and ground wire
     
    Upper radiator hose and coolant bypass hose with mounting bracket
     

  6.  

  1. Unfasten manifold attaching bolts and remove the manifold and gasket from the cylinder head (on the diesel, an engine lifting hook will come off with the manifold).
  2.  



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Fig. Fig. 1: Remove the bolts securing the intake manifold to the cylinder head (note that the carburetor may be left installed on most models)



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Fig. Fig. 2: Withdraw the intake manifold from the cylinder head



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Fig. Fig. 3: Diesel intake and exhaust manifolds-exploded view

  1. Cover the ports on the cylinder block to prevent any foreign objects from falling into the engine.
  2.  

To install:
  1. Replace the gaskets, making sure all surfaces are clean and smooth. Check manifold for warpage as described in the cylinder head overhaul procedures. Repair if necessary.
  2.  
  3. Install the manifold and, working from the center outward, tighten the bolts gradually and in several stages, to specifications.
  4.  
  5. Install the following components in the reverse order of removal as required:

    Coolant bypass hose and bracket
     
    Upper radiator hose
     
    Front engine hanger and ground wire
     
    Secondary air pipe manifold
     
    Spark plugs
     
    Distributor (see the beginning of this section for installation procedures)
     

  6.  
  7. Connect the following components:

    Spark plug wires
     
    Engine harness connectors
     
    Canister hoses
     
    Vacuum hoses (including brake)
     
    Heater hoses
     
    Fuel pump and fuel hoses
     
    Accelerator and cruise control cables
     
    PCV valve hose
     

  8.  
  9. Install the oil dipstick and refill the cooling system. Adjust all the linkages and cables. Set the ignition timing and the idle speed, as described in Engine Electrical .
  10.  

Fuel Injected Engines
323 MODELS

See Figures 4 and 5


CAUTION
Before removing the intake manifold, release the fuel system pressure. (See Fuel System for details.)

  1. Disconnect the negative battery cable and drain the cooling system.
  2.  
  3. Disconnect the accelerator cable from the throttle body. Label and disconnect all air and vacuum hoses from the dynamic chamber and the throttle body.
  4.  
  5. Loosen the hose clamps, then disconnect the air funnel from the air flow meter and the throttle body. On turbocharged engines, disconnect the air funnel from the throttle body and the intercooler.
  6.  
  7. Disconnect the spark plug wires from the distributor and unplug the connector from the ignition coil. Loosen the hose clamp on the flexible hose and disconnect the hose from the air cleaner assembly. Unfasten the bolts from the air cleaner cover and remove the air cleaner/air flow meter assembly from the vehicle.
  8.  



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Fig. Fig. 4: Air intake system on non-turbo 323



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Fig. Fig. 5: Air intake system on turbocharged 323

  1. Disconnect the water hoses and the throttle sensor connector. Remove the retaining nuts and bolts from the throttle body, then separate the throttle body from the intake manifold.
  2.  
  3. Disconnect the hoses and remove the BAC valve. On turbocharged engines, disconnect the water hose for the oil cooler and plug the opening to prevent leakage.
  4.  
  5. On turbocharged engines, unbolt the intake manifold and dynamic chamber assembly from the cylinder block, then lift it out of the vehicle.
  6.  
  7. On non turbocharged engines, unbolt the dynamic chamber from the intake manifold and remove it along with the gasket, then remove the intake manifold.
  8.  
  9. Remove the intake manifold gasket from the cylinder block. Cover or plug the intake ports to prevent anything from falling into the engine.
  10.  
  11. Thoroughly clean the intake manifold and cylinder block gasket mating surfaces. Visually inspect the intake manifold and dynamic chamber for cracks.
  12.  

To install:
  1. Place a new gasket on the cylinder block and lower the intake manifold onto the gasket. On turbocharged engines, attach the dynamic chamber to the intake manifold with a new gasket. Install the retaining nuts and bolts and torque them to 14-19 ft. lbs. (19-26 Nm).
  2.  
  3. Install the remaining components in the reverse order of removal:

    Oil cooler water hose (turbocharged engines)
     
    BAC valve and hoses
     
    Throttle body (with new gasket) and throttle sensor connector
     
    Water and vacuum hoses
     
    Air cleaner/air flow meter assembly, spark plug wires and distributor connector
     
    Air funnel
     
    Accelerator cable
     

  4.  
  5. Refill the cooling system to the proper level and connect the negative battery cable. Check the accelerator cable deflection.
  6.  

626/MX-6 MODELS

See Figure 6


CAUTION
Before removing the intake manifold, release the fuel system pressure. (See Fuel System for details.)

  1. Disconnect the negative battery cable and drain the cooling system.
  2.  
  3. Unplug the air flow meter connector. Disconnect the air cleaner duct (1987 only), secondary air hoses and air control vacuum hoses, then remove the air cleaner. On 1988-89 models, disconnect and remove the air duct along with the No. 1 resonance chamber.
  4.  
  5. Remove the air flow meter and attendant air hoses. On 1988-89 non-turbocharged engines, the No. 2 resonance chamber is connected to the bottom of the flexible air hose by a small hose with a hose clamp, and is retained by one attaching screw. Disconnect and remove the No. 2 resonance chamber.
  6.  
  7. On 1988-89 turbocharged engines, trace the upper hose on the intercooler to the air bypass valve. (There are three hoses connected to the valve.) Loosen the hose clamps and disconnect the hoses. Unbolt and remove the air bypass valve from its mounting bracket, then remove the intercooler.
  8.  
  9. Unfasten the electrical connectors from the throttle body. Disconnect the water and vacuum hoses, then plug the openings.
  10.  
  11. Disconnect the accelerator cable from the throttle body and remove the throttle body (with gasket) from the dynamic chamber.
  12.  
  13. Disconnect the PCV hose and the vacuum pipe assembly. Remove the nuts and bolts that attach the dynamic chamber to the intake manifold and remove it along with the gasket.
  14.  
  15. Unfasten connectors from the fuel injectors, then route the wiring harness off to the side and out of the way. Disconnect the fuel hose from the injector rail and remove the rail assembly with the injectors attached. Plug all the fuel openings.
  16.  
  17. Disconnect the remaining vacuum hoses and remove the EGR pipe.
  18.  
  19. Remove the intake manifold bracket, followed by the intake manifold and gasket. Cover or plug the intake ports with clean rags or masking tape to prevent anything from falling into the engine.
  20.  
  21. Thoroughly clean the intake manifold and cylinder block gasket mating surfaces with a gasket scraper and solvent. Visually inspect the intake manifold and dynamic chamber for cracks.
  22.  

To install:
  1. Place a new gasket on the cylinder block and lower the intake manifold onto the gasket. Install the retaining nuts and torque them to 14-22 ft. lbs. (19-30 Nm).
  2.  
  3. Install the remaining components in the reverse order of removal:

    Intake manifold bracket
     
    EGR pipe and vacuum hoses
     
    Fuel rail and injector harness assembly
     
    Dynamic chamber with new gasket
     
    Vacuum pipe assembly and PCV hose
     
    Throttle body with new gasket
     
    Accelerator cable
     
    Vacuum and water hoses
     
    Throttle body connectors
     
    Intercooler
     
    Air bypass valve with hoses
     
    No. 2 resonance chamber (1988-89 non-turbocharged models only)
     
    Airflow meter
     
    No. 1 resonance chamber
     
    Air duct, air cleaner and air flow meter connector
     

  4.  
  5. Refill the cooling system to the proper level and connect the negative battery cable. Check the accelerator cable deflection.
  6.  



Click image to see an enlarged view

Fig. Fig. 6: 626 throttle body components

929 MODELS

See Figures 7, 8 and 9


CAUTION
Before removing the intake manifold, release the fuel system pressure. Please refer to Fuel System for details on releasing the fuel system pressure.

  1. Disconnect the negative battery cable. Disconnect the coolant hoses and plug them. (The coolant will be drained from the radiator just before the intake manifold is ready to be removed.)
  2.  
  3. Disconnect the air inlet duct from the air cleaner and unplug the air flow meter connector.
  4.  
  5. Locate the two solenoid valves (TICS and purge air control) that are bolted to the front of the air cleaner. Label and disconnect the vacuum hoses.
  6.  
  7. Remove the air cleaner assembly, air flow meter and air funnel.
  8.  
  9. Disconnect the Bypass Air Control (BAC) valve connector and coolant hoses, then remove the valve.
  10.  
  11. Disconnect the throttle sensor connector and the accelerator cable. Remove the throttle body and gasket.
  12.  
  13. Disconnect all vacuum hoses, EGR pipe, EGR position sensor connector, coolant hose and ground wire.
  14.  



Click image to see an enlarged view

Fig. Fig. 7: Intake manifold loosening sequence-929



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Fig. Fig. 8: Always replace the O-ring before installing the intake manifold-929



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Fig. Fig. 9: Intake manifold tightening sequence-929

  1. Remove the wiring harness bracket.
  2.  
  3. Disconnect the air intake pipe from the dynamic chamber with the gasket.
  4.  
  5. Mark the extension manifolds RIGHT and LEFT for assembly reference, as they are not interchangeable. Remove the six extension manifolds with their gaskets from the dynamic chamber.
  6.  
  7. Disconnect the intake air thermosensor connector, vacuum hoses and ground connectors.
  8.  
  9. Remove the attaching nuts and lift the dynamic chamber straight up from the intake manifold studs. Drain the radiator at this time and disconnect all remaining connectors, fuel hoses, and coolant hoses.
  10.  
  11. Using the sequence shown in the illustration, loosen the intake manifold nuts in two stages. Lift the intake manifold from the engine and remove the two intake manifold gaskets. Insert clean rags into the intake ports or cover them with masking tape to prevent anything from falling into the engine.
  12.  
  13. Immerse the intake manifold in a suitable solvent and blow it dry with compressed air. Visually inspect the intake manifold for cracks, warpage or any other type of damage and replace as necessary. Remove all gasket material from the seating surface on the manifold and the engine. Forward of one of the studs that secures the dynamic chamber is an O-ring that seals the manifold to the dynamic chamber. Remove this O-ring and replace it with a new one.
  14.  

To install:
  1. Place the new intake manifold gaskets onto the cylinder block and lower the manifold over the gaskets. Install the intake manifold washers with the white paint marks facing up. Install the retaining nuts and torque them in two stages to 14-18 ft. lbs. (19-24 Nm) using the sequence shown in the illustration.
  2.  
  3. Install the remaining components in the reverse of the removal procedure:
    1. Connectors, fuel hoses, coolant hoses and vacuum hoses.
    2.  
    3. Dynamic chamber. Torque the retaining nuts to 14-18 ft. lbs. (19-24 Nm)..
    4.  
    5. Intake air thermosensor ground connectors and vacuum hoses.
    6.  
    7. Extension manifolds with new gaskets and O-rings.
    8.  
    9. Intake air pipe with new gaskets and wiring bracket.
    10.  
    11. Ground wire, coolant hose, EGR position connector, EGR pipe and vacuum hoses.
    12.  
    13. Throttle body with new gasket, accelerator cable and throttle sensor connector. Check the deflection of the accelerator cable. If not within 0.04-0.12 in. (1-3mm), adjust with the nuts on the cable bracket.
    14.  
    15. BAC valve, coolant hoses and connector.
    16.  
    17. Air funnel, air hoses, air flow meter, and air cleaner assembly.
    18.  
    19. TICS and purge control solenoid valves, air flow meter connector, vacuum chamber and air duct.
    20.  

  4.  
  5. Make sure that all hose connections are tight, then refill the cooling system to the proper level. Connect the negative battery cable. Start the engine and check for leaks.
  6.  

 
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