Grand Marquis V8-351 5.8L (1982)
Liquid Vapor Separator: Description and Operation
Fig.62 - Fuel Tank Vapor Valve
DESCRIPTION
All fuel tank vapor valves, Fig. 62, use a small orifice which allows only vapor and not fuel to pass into the line going to the vapor storage
canister. This assembly is mounted on the fuel tank. Fuel vapors trapped in the sealed fuel tank are vented through the vapor valve assembly. The
vapors leave the valve assembly through a single vapor line and continue to the charcoal canister for storage, until they are purged into the engine.
On vehicles equipped with fuel/vapor return lines, vapors created in the fuel line are continuously vented back to the fuel tank. This prevents
engine surging from fuel enrichment.