LeSabre V6-231 3.8L VIN A 2-bbl (1984)
Thermal Vacuum Valve - Carb: Description and Operation
Choke Vacuum Break Thermal Vacuum Switch (CVB-TVS)
The CVB-TVS provides a richer choke operation when the air entering the carburetor is less than the specified temperature. The CVB-TVS controls
the vacuum to the secondary vacuum break. When the engine is started and the air temperature is less than specified, the CVB-TVS closes and prevents
the vacuum break from pulling, to provide a richer start and improved driveability. If the air temperature is greater than specified, both vacuum breaks
pull the choke to its leanest position.