Thermostatic Air Cleaner: Testing and Inspection

TAC DIAGNOSIS

1. Inspect system to be sure all hoses and heat stove tube are connected. Check for kinked, plugged or deteriorated hoses.

2. Check for presence and condition of air cleaner to throttle body gasket and cover seal.

3. With air cleaner assembly installed, damper door should be open to outside air.

4. Start engine. Watch damper door in air cleaner fresh air inlet (air inlet duct disconnected). When engine is first started, damper door should move and close off outside air. As air cleaner warms up, damper door should open slowly to outside air.

5. If the air cleaner fails to operate as described above, or if a driveability problem occurs during warm-up, test the vacuum motor.


TAC VACUUM MOTOR TEST

1. With engine off, disconnect vacuum hose at vacuum diaphragm motor.

2. Apply at least 23 kPa (7 in. Hg.) of vacuum to the vacuum diaphragm motor. Damper door should completely block off to outside air when vacuum is applied. If not, check linkage operation.

3. With vacuum still applied, trap vacuum in vacuum diaphragm motor by pinching hose. Damper door should remain closed. If not, replace vacuum diaphragm motor assembly. (Failure of the vacuum diaphragm motor assembly is more likely to be caused from binding linkage than from a failed diaphragm. This should be checked first, before replacing the diaphragm.)

4. If vacuum motor checks OK, check vacuum hoses and connections. If OK, replace the temperature sensor.


Hesitation during warm-up can be caused by:

^ Heat stove tube disconnected.

^ Vacuum diaphram motor inoperative (open to outside air).

^ No manifold vacuum to air cleaner

^ Damper door does not move.

^ Missing air cleaner to throttle body seal.

^ Missing air cleaner cover seal or loose cover.

Loose air cleaner. Lack of power, sluggish, or spongy, on a hot engine can be caused by:

^ Damper door does not open to outside air.

^ Temperature sensor doesn't bleed off vacuum.