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Intake Manifold

REMOVAL & INSTALLATION

1.5L Engine

Fig. 1: Exploded view of the intake and exhaust manifold mounting — 1.5L (4G15) engine

  1. Relieve the fuel system pressure.

    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.

  2. Disconnect battery negative cable and drain the cooling system.

    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.

  3. Disconnect the upper radiator hose, heater hose and water bypass hose.
  4. Remove the thermostat housing from intake manifold.
  5. Disconnect the accelerator cable, breather hose and air intake hose.
  6. Remove all vacuum hoses and pipes as necessary, including the brake booster vacuum line.
  7. Remove the throttle body assembly.
  8. Disconnect the high pressure fuel line and the fuel return hose.
  9. Tag and detach the electrical connectors from the oxygen sensor, coolant temperature sensor, intake air temperature, idle speed control assembly, EGR temperature sensor, spark plug wires and distributor.
  10. Remove the fuel rail, fuel injectors, pressure regulator and insulators.
  11. Remove the EGR valve from the intake manifold.
  12. Remove the intake manifold support bracket and remove the engine mount support bracket.
  13. Remove the intake manifold mounting bolts and remove the intake manifold assembly.

    To install:

  14. Clean all gasket material from the cylinder head intake mounting surface and intake manifold assembly. Check both surfaces for cracks or other damage. Check the intake manifold water passages and jet air passages for clogging. Clean if necessary.
  15. Using a straight edge, measure the distortion of the intake manifold-to-cylinder head. Total distortion or warpage should be 0.006 inches (0.15mm or less).
  16. Install a new intake manifold gasket to the head and install the manifold. Torque the manifold in a crisscross pattern, starting from the inside and working outwards to 13 ft. lbs. (18 Nm).
  17. Install the intake manifold support bracket and torque the mounting bolts to 16 ft. lbs. (22 Nm).
  18. Install the engine mount support bracket and torque the mounting bolts to 26 ft. lbs. (36 Nm).
  19. Using a new gasket, install the EGR valve and torque the mounting bolts to 15 ft. lbs. (21 Nm).
  20. Using new insulators and O-rings, install the fuel delivery pipe, injectors and pressure regulator to the engine. Torque the retaining bolts to 7–9 ft. lbs. (10–14 Nm).
  21. Attach the electrical connectors to the oxygen sensor, coolant temperature sensor, intake air temperature, idle speed control assembly, EGR temperature sensor, spark plug wires and distributor.
  22. Using a new O-ring for the feed pipe and a new clamp for the return pipe, install the fuel hoses.
  23. Install the throttle body assembly.
  24. Install the vacuum hoses and pipes as necessary, including the brake booster vacuum line.
  25. Install and adjust the accelerator cable. Install the breather and air intake hose.
  26. Using a new gasket, install the thermostat housing to the intake manifold and tighten the mounting bolts to 13 ft. lbs. (18 Nm).
  27. Connect the upper radiator hose, heater hose and water bypass hose. Be sure to use new hose clamps.
  28. Fill the system with coolant.
  29. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely.
  30. Check and adjust the idle speed and ignition timing.
  31. Once the vehicle has cooled, recheck the coolant level.
1.8L Engine

Fig. 2: Exploded view of the intake manifold mounting — 1993 1.8L engine

Fig. 3: Exploded view of the intake manifold mounting — 1994–00 1.8L engine

  1. Relieve the fuel system pressure.

    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.

  2. Disconnect battery negative cable and drain the cooling system.

    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.

  3. Disconnect the accelerator cable and the air intake hose.
  4. Tag and detach the electrical connectors from the oxygen sensor, coolant temperature sensor, idle speed control assembly, EGR temperature sensor, oil pressure switch, spark plug wires and distributor.
  5. Disconnect the wiring from the throttle position sensor, fuel injectors and disconnect the ground cables.
  6. Remove all vacuum hoses and pipes as necessary, including the brake booster and PCV vacuum lines.
  7. Disconnect the upper radiator hose, heater hose and water bypass hose.
  8. Disconnect the high pressure fuel line and the fuel return hose.
  9. Remove the fuel rail, fuel injectors, pressure regulator and insulators.
  10. Remove the intake manifold support bracket.
  11. If the thermostat housing is preventing removal of the intake manifold, remove it.
  12. Remove the intake manifold mounting bolts/nuts and remove the intake manifold assembly.

    To install:

  13. Clean all gasket material from the cylinder head intake mounting surface and intake manifold assembly. Check both surfaces for cracks or other damage. Check the intake manifold water passages and jet air passages for clogging. Clean if necessary.
  14. Using a straight edge, measure the distortion of the intake manifold-to-cylinder head. Total distortion or warpage should be 0.006 inches (0.15mm or less).
  15. Install a new intake manifold gasket to the head and install the manifold. Torque the manifold in a crisscross pattern, starting from the inside and working outwards to 14 ft. lbs. (20 Nm).
  16. If removed, install the thermostat housing.
  17. Install the intake manifold brace bracket.
  18. Install the fuel delivery pipe, injectors and pressure regulator to the engine. Torque the retaining bolts to 108 inch lbs. (12 Nm).
  19. Using a new O-ring for the feed pipe and a new clamp for the return pipe, install the fuel hoses.
  20. Connect the upper radiator hose, heater hose and water bypass hoses.
  21. Install the vacuum hoses and pipes as necessary. Be sure to connect the brake booster and PCV vacuum lines.
  22. Connect the wiring to the throttle position sensor, fuel injectors and connect the ground cables.
  23. Attach the electrical wiring to the oxygen sensor, coolant temperature sensor, idle speed control assembly, EGR temperature sensor, oil pressure switch, spark plug wires and distributor.
  24. Connect and adjust the accelerator cable and install the air intake hose.
  25. Fill the system with coolant.
  26. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely.
  27. Check and adjust the idle speed and ignition timing.
  28. Once the vehicle has cooled, recheck the coolant level.
2.0L SOHC Engine

Fig. 4: Exploded view of the intake manifold mounting — 2.0L SOHC engine

  1. Relieve the fuel system pressure.

    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.

  2. Disconnect the battery negative cable.
  3. Drain the cooling system.

    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. Disconnect the accelerator cable and air intake hose.
  5. Disconnect the upper radiator hose, heater hose and water bypass hose.
  6. Unplug the vacuum connection at the power brake booster and the PCV valve if still connected. Disconnect all remaining vacuum hoses and pipes as necessary.
  7. Disconnect the high pressure fuel line, fuel return hose and remove throttle control cable brackets.
  8. Tag and detach the electrical connectors from the oxygen sensor, coolant temperature sensor, thermo switch, idle speed control assembly, EGR temperature sensor, distributor, fuel injectors and spark plug wires. Position the engine wiring harness aside.
  9. Matchmark the distributor housing to the intake manifold, and remove the distributor.
  10. Remove the intake manifold bracket and the engine hanger.
  11. If the thermostat housing is preventing removal of the intake manifold, remove it.
  12. Remove the intake manifold mounting bolts and remove the intake manifold assembly. Disassemble manifold from the intake plenum on a work bench as required.

    To install:

  13. Clean all gasket material from the cylinder head intake mounting surface and intake manifold assembly. Check both surfaces for cracks or other damage. Check the intake manifold water passages and jet air passages for clogging. Clean if necessary.
  14. Assemble the intake manifold assembly using all new gaskets. Torque air intake plenum bolts to 11–14 ft. lbs. (15–19 Nm).
  15. Install a new intake manifold gasket to the head and install the manifold. Torque the manifold in a crisscross pattern, starting from the inside and working outwards to 11–14 ft. lbs. (15–19 Nm).
  16. Install the fuel delivery pipe, injectors and pressure regulator to the engine. Torque the retaining bolts to 4 ft. lbs. (6 Nm).
  17. Install the thermostat housing, intake manifold brace bracket, and engine hanger bracket.
  18. Connect or install all hoses, cables and electrical connectors that were removed or disconnected during the removal procedure.
  19. Align the distributor matchmarks and install the distributor.
  20. Fill the system with coolant.
  21. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely.
  22. Adjust the accelerator cable. Check and adjust the idle speed and ignition timing.
  23. Once the vehicle has cooled, recheck the coolant level.
1.6L and 2.0L DOHC Engines

Fig. 5: Exploded view of the intake manifold and related components — 1.6L and 2.0L DOHC engine

  1. Relieve the fuel system pressure.

    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.

  2. Disconnect battery negative cable and drain the cooling system.

    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.

  3. Disconnect the accelerator cable and air intake hose.
  4. Disconnect the coolant hose from the throttle housing.
  5. Detach the vacuum connection at the power brake booster and the PCV valve if still connected. Disconnect all remaining vacuum hoses and pipes as necessary.
  6. Disconnect the high pressure fuel line, fuel return hose and remove throttle control cable brackets.
  7. Tag and detach the electrical connectors from the oxygen sensor, coolant temperature sensor, thermo switch, throttle position sensor, idle speed control assembly, EGR temperature sensor, distributor, fuel injectors and spark plug wires. Position the engine wiring harness aside.
  8. Remove the intake manifold bracket.
  9. Remove the intake manifold mounting bolts and remove the intake manifold assembly. Disassemble manifold on a work bench as required.

    To install:

  10. Clean all gasket material from the cylinder head intake mounting surface and intake manifold assembly. Check both surfaces for cracks or other damage. Check the intake manifold water passages and jet air passages for clogging. Clean if necessary.
  11. Assemble the intake manifold assembly using all new gaskets.
  12. Install a new intake manifold gasket to the head and install the manifold. Torque the manifold in a crisscross pattern, starting from the inside and working outwards to 11–14 ft. lbs. (15–20 Nm).
  13. Install the fuel delivery pipe, injectors and pressure regulator to the engine. Torque the retaining bolts to 4 ft. lbs. (6 Nm).
  14. Install the intake manifold brace bracket and tighten bolts to 13–18 ft. lbs. (18–25 Nm).
  15. Connect or install all hoses, cables and electrical connectors that were removed or disconnected during the removal procedure.
  16. Fill the system with coolant.
  17. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely.
  18. Adjust the accelerator cable.
  19. Check and adjust the idle speed and ignition timing.
  20. Once the vehicle has cooled, recheck the coolant level.
2.4L Engine

Fig. 6: Detach the A/C temp electrical connector

Fig. 7: Unplug the connector from the Throttle Position (TP) sensor

Fig. 8: Detach the connectors from all of the fuel injectors

Fig. 9: Unplug the main engine harness junction electrical connector

Fig. 10: Detach the Camshaft Position (CMP) sensor connector

Fig. 11: Unplug the connector from the Manifold Absolute Pressure (MAP) sensor

Fig. 12: Detach the connector for the Idle Air Control (IAC) motor

Fig. 13: Remove the engine harness retaining bracket bolts, then move the harness out of the way

Fig. 14: Remove the accelerator cable end from the throttle lever

Fig. 15: Remove the accelerator cable bracket retaining bolts . . .

Fig. 16: . . . then position the accelerator cable out of the way

Fig. 17: Disconnect the EGR hose and the three vacuum hoses on the back of the intake manifold

Fig. 18: Remove the hose shown here from the throttle body

Fig. 19: Remove the brake booster vacuum hose from the back of the intake manifold

Fig. 20: Remove the fuel feed line-to-fuel rail retaining fitting bolts . . .

Fig. 21: . . . then remove the fuel feed line from the fuel injector rail

Fig. 22: From underneath the vehicle, remove the two intake manifold support bracket bolts

Fig. 23: Remove the intake manifold retaining bolts . . .

Fig. 24: . . . then remove the manifold from the cylinder head

  1. Relieve the fuel system pressure.

    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.

  2. Disconnect battery negative cable and drain the cooling system.

    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.

  3. Disconnect the accelerator cable, breather hose and air intake hose.
  4. Disconnect the coolant hose from the throttle housing.
  5. Detach the vacuum connection at the power brake booster and the PCV valve if still connected. Disconnect all remaining vacuum hoses and pipes as necessary.

    CAUTION
    Fuel injection systems remain under pressure after the engine has been turned OFF. Properly relieve fuel pressure before disconnecting any fuel lines. Failure to do so may result in fire or personal injury.

  6. Disconnect the high pressure fuel line, fuel return hose and remove throttle control cable brackets.
  7. Tag and unplug the electrical connectors from the coolant temperature sensor, coolant temperature gauge, IAC valve, ignition coil, EGR temperature sensor, knock sensor, oxygen sensor, throttle position sensor, distributor, A/C temperature sensor, fuel injectors and ignition power transistor. Position the engine wiring harness aside.
  8. Label and disconnect the spark plug wires from the spark plugs.
  9. Remove the intake manifold stay bracket.
  10. Remove the intake manifold mounting bolts and remove the intake manifold assembly. Disassemble manifold on a work bench as required.

    To install:

  11. Clean all gasket material from the cylinder head intake mounting surface and intake manifold assembly. Check both surfaces for cracks or other damage. Check the intake manifold water passages and jet air passages for clogging. Clean if necessary.
  12. Assemble the intake manifold assembly using all new gaskets.
  13. Position a new intake manifold gasket on the head, then install the manifold. Torque the manifold in a crisscross pattern, starting from the inside and working outwards to 15 ft. lbs. (20 Nm) for bolts, and to 26 ft. lbs. (35 Nm) for nuts on 1994 vehicles or 15 ft. lbs. (20 Nm) for nuts on 1995–00 vehicles.
  14. Install the fuel delivery pipe, injectors and pressure regulator to the engine. Torque the retaining bolts to 4 ft. lbs. (6 Nm).
  15. Install the intake manifold brace bracket and tighten bolts to 21 ft. lbs. (29 Nm).
  16. Connect or install all hoses, cables and electrical connectors that were removed or disconnected during the removal procedure.
  17. Fill the system with coolant.
  18. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely.
  19. Adjust the accelerator cable. Check and adjust the idle speed and ignition timing.
  20. Once the vehicle has cooled, recheck the coolant level.
3.0L and 3.5L Engines

Fig. 25: Exploded view of air intake plenum assembly — 3.0L DOHC engine

Fig. 26: Intake manifold and related components — 3.0L DOHC engine

Fig. 27: Exploded view of air intake plenum assembly — 3.0L SOHC engine

Fig. 28: Exploded view of the intake manifold mounting — 3.0L SOHC engine

Fig. 29: Exploded view of air intake plenum assembly — 3.5L engine

Fig. 30: Exploded view of the intake manifold mounting — 3.5L engine

  1. Relieve the fuel system pressure.

    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.

  2. Disconnect battery negative cable and drain the cooling system.

    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.

  3. Remove the air intake hose(s).
  4. Disconnect the accelerator control cables from the throttle body.
  5. Tag and disconnect the vacuum hoses including the brake booster hose.
  6. Tag and detach the wire harness connectors.
  7. Disconnect the high pressure and return fuel hoses.
  8. Disconnect EGR pipe and remove the EGR valve and EGR temperature sensor from the intake plenum assembly.
  9. If equipped, remove the manifold pressure sensor.
  10. Remove the plenum retaining bracket.
  11. Remove the plenum retaining nuts and bolts and remove the air intake plenum from the intake manifold. Discard the gasket.
  12. Remove the upper timing belt covers.
  13. Remove the water pump stay bracket.

    NOTE: It is not necessary to remove the fuel injectors from the intake unless the manifold assembly is being replaced.

  14. Remove the fuel rail with the injectors attached.
  15. Disconnect the coolant hoses from the intake manifold. Be sure to note the connections.
  16. Remove the intake manifold mounting nuts and remove the intake manifold.
  17. Clean the gasket mounting surfaces.

    To install:

  18. Check all items for cracks, clogging and warpage. Maximum warpage is 0.0059 inches (0.15mm). Replace any questionable parts.
  19. Thoroughly clean and dry the mating surfaces of the heads, intake manifold and air intake plenum.
  20. Install new intake manifold gaskets to the cylinder heads with the adhesive side facing up.
  21. Place the manifold on the cylinder heads.
  22. Lubricate the studs lightly with oil and install the nuts.
  23. For vehicles produced up to and including November of 1993, tighten the mounting nuts as follows:
    1. Front bank nuts: 27–43 inch lbs. (3–5 Nm)
    2. Rear bank nuts: 9–11 ft. lbs. (12–15 Nm)
    3. Front bank nuts: 9–11 ft. lbs. (12–15 Nm)
  24. For vehicles produced after November of 1993, tighten the mounting nuts as follows:
    1. Front bank nuts: 48–72 inch lbs. (5–8 Nm)
    2. Rear bank nuts to: 14–17 ft. lbs. (20–23 Nm)
    3. Front bank nuts to: 14–17 ft. lbs. (20–23 Nm)
  25. Using new clamps, connect the coolant hoses to the intake manifold.
  26. Using new O-rings, install the fuel rail assembly, if removed. Tighten the mounting bolts to 7–9 ft. lbs. (10–13 Nm).
  27. Install a new intake air plenum gasket and install the plenum. Tighten the retaining nuts and bolts evenly and gradually to 13 ft. lbs. (18 Nm).
  28. Install the retaining bracket and tighten the retaining bolts to 13 ft. lbs. (18 Nm).
  29. If removed, install the manifold pressure sensor.
  30. Using a new gasket, install the EGR valve and tighten the bolts to 16 ft. lbs. (22 Nm).
  31. Install the EGR temperature sensor and tighten the fitting to 7–9 ft. lbs. (10–12 Nm).
  32. Connect the EGR pipe and tighten the fittings to 43 ft. lbs. (60 Nm).
  33. Replace the O-ring and connect the high pressure fuel hose. Tighten the retaining bolts to 48 inch lbs. (5 Nm).
  34. Using a new hose clamp, connect the fuel return hose.
  35. Install the water pump stay bracket.
  36. Install the upper timing belt covers.
  37. Connect the harness connector and vacuum hoses.
  38. Connect and adjust the accelerator cables.
  39. Install the air intake hose(s).
  40. Fill the system with coolant.
  41. Connect the negative battery cable, run the vehicle until the thermostat opens, fill the radiator completely.
  42. Check and adjust the idle speed and ignition timing.
  43. Once the vehicle has cooled, recheck the coolant level.

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