Ninety-Eight FWD V6-181 3.0L (1985)
Thermal Vacuum Valve - Carb: Testing and Inspection
Choke Vacuum Break Thermal Vacuum Switch (CVB-TVS)
When cold, the valve should be closed. If necessary, cool the valve below its calibration point. Replace if defective.
At normal operating temperature, the valve should be open. This can be checked by disconnecting the top hose and connecting a vacuum gauge to it.
There should be vacuum present with engine running. A valve stuck in the closed position can cause poor start condition and/or stalling after start
up.
Fig. 27 Choke Break Thermal Vacuum Switch (CB-TVS). 2 port type
2 Port Type
With engine coolant temperature below the switching point, passage of vacuum should be restricted between ports 1 and 2, Fig. 27.
With engine coolant temperature above the switching point, vacuum should pass freely through ports 1 and 2, Fig. 27.
