Q: How is the Canister Purge Valve and Vapor Canister work on Ford F-250?
A: The system for emission control prevents the fuel vapors from being released into the atmosphere. It is a sealed carburetor bowl and a check valve fuel tank filler cap which helps have a "closed" fuel system. A vapor relief valve integrated into the fuel tank controls vapor pressure while charcoal canister is connected to the sources of vapors. The engine purges the canister off vapor by feeding it to the engine when it is running. In carbureted engines, the canister gets vapor through valves such as thermal vent valve and a bowl vent solenoid. On the other hand, for fuel-injected engines, outlet of canister connects with an electrically activated canister purge solenoid controlled by EEC PCM for combustion of vapor.