Diplomat V8-318 5.2L VIN K 2-bbl (1982)
Purge Control Valve: Description and Operation
OPERATION
This valve--in the carbon canister--controls fuel vapor flow during various engine operating modes.
The control is provided by a vacuum signal from either the spark port, EGR port or intake manifold and opens or closes the valve accordingly.
When the engine is off, the vapors from the fuel tank and carburetor fuel bowl are routed through the purge control valve and into the carbon
canister for storage.
During normal cruise conditions, spark port or EGR vacuum is strong enough to open the orifice in the purge control valve to allow fuel vapors to
flow from the carburetor canister through the purge line to a connection in the PCV tube or into the carburetors spacer. At the same time, the
vapors from the fuel tank are also directed into the purge line. At idle and low speed cruise conditions, spark port or EGR port vacuum is not
enough to open the orifice in the purge control valve so that the fuel vapors are then routed to the carbon canister.
