Cutlass Ciera FWD L4-151 2.5L (1982)
Thermal Vacuum Valve - Carb: Description and Operation
Choke Vacuum Break Distributor TVS
Purpose
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 preventing the vacuum break from pulling, providing a richer start and improved driveability.
If the air temperature is greater than specified, both vacuum breaks pull the choke to its leanest position.
Operation
Switch--located in the air cleaner--controls vacuum to the thermostatic air cleaner, choke vacuum break and distributor vacuum
advance--according to engine temperature.
When temperatures are below the calibration value of the switch;
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No vacuum to thermostatic air cleaner
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No vacuum to choke vacuum break--runs richer
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Vacuum advance receives full manifold vacuum.
When temperatures are above the calibration value of the switch;
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Manifold vacuum is directed to the thermostatic air cleaner and choke vacuum break ports
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Vacuum advance port is blocked--preventing distributor advance above the switching point.
