MR2 L4-132 2164cc 2.2L DOHC (5S-FE) (1993)
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Thermal Vacuum Valve - EVAP: Description and Operation
PURPOSE
The thermal vacuum valve (TVV) prevents charcoal canister purging below 129° F (54° C). Low temperature purging is delayed to prevent the
possible leaning of the cold fuel mixture.
LOCATION
The valve is threaded into the water jacket near the distributor.
CONSTRUCTION
The valve consists of a bimetallic spring and a sealing plate.
OPERATION
During low water temperature, the bimetallic spring contracts, closing the vacuum passage through the TVV. When the temperature rises above
129° F (54° C), the spring expands opening the vacuum passage, allowing purge vacuum to reach the canister.