Intake manifold — removal and installation
Warning: Wait until the engine is completely cool before beginning this procedure.
Removal
1. Relieve the fuel system pressure (see Fuel and exhaust systems), then disconnect the cable from the negative battery terminal (see Engine electrical systems).
2. Remove the air intake duct and resonator (see Fuel and exhaust systems). Remove the cowl cover and vent tray/sub-frame (see Body). Note: To remove the vent tray/sub-frame, the wiper motor and linkage must be completely removed (see Chassis electrical system).
3. Remove the engine cover.
4. Disconnect the vacuum hose connection tube from the hoses and retainers at the firewall (see illustration).
i. 4 Disconnect the connection tube clamps and the tube retainers
5. Drain the cooling system (see Tune-up and routine maintenance) and remove the heater hoses going into the firewall (see Cooling, heating and air conditioning systems).
6. Remove the throttle body from the intakemanifold (see Fuel and exhaust systems) and disconnect the vent tubes.
7. Disconnect the electrical connector tothe vacuum switching valve (see illustration) then remove the harness bracket fasteners (seeillustrations) and move the harness out of the way.
i. 7a Disconnect the electrical connector to thevacuum switching valve
i. 7b Remove the harness bracket upper fasteners…
i. 7c… and the lower fastener
8. Disconnect the fuel inlet line to the fuelrail (see Fuel and exhaust systems).
9. From under the intake manifold, disconnect the tumble control valve actuator electrical connector (see illustration).
i. 9 Tumble control valve actuator electrical connector
10. Disconnect the electrical connectors from the fuel rail, remove the harness mounting fasteners and set the harness to the side. Disconnect and remove the main harness connector to the intake manifold and tumble control valves.
11. Using test leads, apply battery voltage toterminal no. 8 of the tumble control valve electrical connector and ground the no. 4 terminal
(see illustrations); this will close the tumble control valve to prevent it from being damaged when the manifold is removed.
i. 11a Tumble control valve connector pin identification
i. 11b DO NOT apply voltage longer than three seconds or touch any other terminals or the actuator may be damaged
Caution: When the tumble control valves are in the open position, part of the valve is in the manifold inlet and the other half is inside the cylinder head. If the valves are not closed when the intake manifold is removed, the valves may be damaged. Also, don’t apply
voltage longer than three seconds. If the voltage is applied longer than three seconds, or any other terminals are touched, the actuator may be damaged.
12. Remove the intake manifold lower bolts (see illustration).
i. 12 Intake manifold lower bolt locations
13. Unscrew the intake manifold upper mounting fasteners (see illustration) and remove the manifold.
i. 13 Intake manifold upper mounting bolt locations
Installation
14. Clean the mating surfaces of the intake manifold and the cylinder head mounting surface with lacquer thinner or acetone. If the gasket shows signs of leaking, check the manifold for warpage with a straight edge. If the manifold is warped it must be replaced.
15. Press a new gasket into the grooves on the intake manifold (see illustration). Install the manifold and gasket over the studs on the cylinder head.
i. 15 Press the gasket into the groove on the intake manifold
16. Tighten the manifold-to-cylinder head nuts/bolts in three or four equal steps to thetorque listed in this Chapter’s Specifications. Work from the center out toward the ends to avoid warping the manifold.
17. Install the remaining parts in the reverse order of removal. Check the coolant level, adding as necessary (see Tune-up and routine maintenance).
18. Run the engine and check for coolant and vacuum leaks.