Intake Air Plenum: Service and Repair

Intake Plenum Chamber:

CAUTION: Use care in removing and handling the plenum assembly to avoid damaging the ignition module which is attached to the underside of the plenum.

REMOVAL:

1. Disconnect the negative battery cable.
2. Drain the coolant. (Coolant circulating through the plenum must be drained before removing the plenum).
3. Remove the air intake duct.
4. Remove the throttle cable cover attaching hardware and cover.
5. Remove the throttle and cruise control cables from the throttle body.
6. Remove the hold down clamp, and set the cables aside.
7. Disconnect the electrical connectors from:
^ Throttle Position Sensor (TPS).
^ Idle Air Control (IAC) valve.
^ Manifold Air Temperature (MAT) sensor.
8. Remove the coolant bleed hose from the plenum.
9. Remove the power brake hose from the plenum.
10. Remove the vacuum hose between the fuel pressure regulator and the plenum.
11. Remove the left and right vacuum hoses at mid-plenum.
12. Remove the Manifold Absolute Pressure (MAP) sensor attaching screws.
13. Remove the vacuum hose from the MAP sensor, and set the sensor aside.
14. Remove the bolts retaining the plenum assembly to the injector housings.
15. Remove the PCV dual hose fitting from the fitting.
16. Remove the canister hose from the plenum.
17. Lift the front of the plenum assembly and disconnect:
^ Left and right fresh air hoses from the throttle body extension.
^ Canister vacuum signal hose from the throttle body extension.
^ Electrical connectors from the ignition module.
18. Remove the plenum assembly and gaskets, discard the gaskets.
19. Cover the intake ports with tape to prevent dirt and any foreign material from entering.

DISASSEMBLE (IF REPLACING THE PLENUM):

1. Remove the throttle body extension and throttle body.
2. Remove the MAP sensor bracket from the plenum.
3. Remove the ignition module.

CAUTION: Use care in cleaning old gasket material from machined aluminum surfaces. Sharp tools may damage sealing surfaces.

4. Clean the gasket sealing surfaces.

ASSEMBLY (IF REPLACING THE PLENUM):

1. Install the ignition module.
2. Install the MAP sensor bracket, and tighten the bolts to 10 Nm (89 lb.in).
3. Install the throttle body and extension.

INSTALLATION:

1. Remove the tape from the intake ports.
2. Position the plenum assembly on the injector housings, and guide the MAP sensor vacuum hose under the fuel lines, and connect:
^ Electrical connectors to the ignition module.
^ Canister vacuum signal hose to the throttle body extension.
^ Left and right fresh air hoses to the throttle body extension.
3. Install the PCV valve dual hose fitting.
4. Connect the canister hose to the plenum.
5. Position new plenum gaskets.

Plenum Bolt Tightening Sequence:

6. Install the plenum bolts and tighten to 26 Nm (20 lb.ft) in the sequence shown in illustration.
7. Connect the vacuum hose to the MAP sensor.
8. Install the MAP sensor attaching screws.
9. Connect the left and right vacuum hoses to mid-plenum.
10. Install the vacuum hose between the fuel pressure regulator and the plenum.
11. Connect the coolant air bleed hose.
12. Connect the power brake booster vacuum hose to the plenum.
13. Connect the electrical connectors to the TPS, IAC valve, and MAT sensor.
14. Connect the throttle and cruise control cables.
NOTE: Make sure the throttle and cruise control cables do not hold the throttle open.
15. Install the cable hold down clamp.
16. Install the cable shield and attaching hardware.
17. Install the air intake duct.
18. Fill the cooling system to the proper level.
19. Connect the negative battery cable.