Comanche 2WD L4-150 2.5L VIN E TBI (1989)
Thermostatic Air Cleaner: Testing and Inspection
TAC Heat Off Position
1.
With the engine not running, the air valve should be fully open to incoming ambient air (heat OFF position).
TAC Heat On Position
1.
Start the engine.
2.
With engine cold and running, and ambient temperature in the engine compartment below 85°F, the heat control door in the snorkel should be in
the up (heat on) position.
3.
Depress the throttle rapidly (1/2 to 3/4 position) and release. The air valve should briefly remain stationary and then move toward the heat OFF
position and then back to the heat ON position.
4.
Warm the engine to normal operating temperature and observe the air valve. The air valve should be fully open to ambient air above 55°F
5.
Stop the engine.
6.
If the air valve does not function as described in the previous test, inspect for a mechanical bind in the snorkel, disconnected or leaking vacuum
hoses, and vacuum leaks at the vacuum motor, air temperature sensor, or intake manifold.
7.
If the air valve manually operates freely and the hoses are not leaking or disconnected, connect a vacuum hose from an intake manifold source
directly to the vacuum motor and start the engine.
8.
If the air valve closes, the air temperature sensor, thermal check valve or delay valve is defective and must be replaced. If the air valve does not
close, replace the vacuum motor.
AIR TEMPERATURE SENSOR
1.
Disconnect the vacuum hoses from the air temperature sensor at the throttle body cover.
2.
Connect an hand operated vacuum pump to the vacuum source side of the sensor and a vacuum gauge to the vacuum motor side of the sensor.
3.
Apply 14 in. Hg vacuum to the sensor.
4.
When the sensor temperature is below 85°F vacuum should be maintained.
