Ford F150 Pickup. Instruction — part 1641

EVAP canister purge valve is part of Enhanced EVAP system that is controlled by PCM. See Fig. 65 and Fig.
66 . This valve controls flow of vapors (purging) from EVAP canister to intake manifold during various engine
operating modes. EVAP canister purge valve is a normally closed valve. The electronic EVAP canister purge
valve controls the flow of vapors electronically by way of a solenoid thereby, eliminating the need for an
electronic vacuum regulator and vacuum diaphragm. See Fig. 67 .

Fig. 65: Identifying EVAP Canister Purge Valve (Escort, Focus, LS, Mustang, Sable, Taurus &
Thunderbird)
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline

Fig. 66: Identifying EVAP Canister Purge Valve (All Others)
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline

Fig. 67: Identifying Electronic EVAP Canister Purge Valve (Focus 2.3L, LS & Thunderbird)
Courtesy of FORD MOTOR CO.

Fuel Filler Cap

The fuel filler cap is used to prevent fuel spill and close the evaporative emission/fuel system to atmosphere.
Some vehicles may have a Fuel Cap Off Indicator Lamp (FCIL) in the instrument cluster which will illuminate
when there is a failure in the vapor management system that may be due to the fuel filler cap not being sealed.

ON-BOARD REFUELING VAPOR RECOVERY EVAP SYSTEM

The basic elements forming the ORVR system operation are as follows when fuel is dispensed: See Fig. 68 and
Fig. 69 .

1. The fuel filler pipe forms a seal to prevent vapors from escaping the fuel tank, while liquid is entering the

fuel tank (liquid in the one inch diameter tube blocks vapors from rushing back up the fuel filler pipe).

2. A fuel vapor control valve controls the flow of vapors out of the fuel tank (valve closes when liquid level

reaches a height associated with the fuel tank usable capacity). This valve accomplishes the following:

z

Limits the total amount of fuel that can be dispensed into the fuel tank.

z

Prevents liquid gasoline from exiting the fuel tank when submerged (and also when tipped well

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline

beyond a horizontal plane as part of the vehicle roll-over protection in road accidents).

z

Minimizes vapor flow resistance during anticipated refueling conditions.

3. Fuel vapor tubing connects the fuel vapor control valve to the EVAP canister. This routes the fuel tank

vapors (displaced by the incoming liquid) to the EVAP canister.

4. A check valve in the bottom of the fuel filler pipe prevents liquid from rushing back up the fuel filler pipe

during the liquid flow variations associated with the filler nozzle shut-off.

Between refueling events, the EVAP canister is purged with fresh air so that it may be used again to store
vapors accumulated during engine soaks or subsequent refueling events. The vapors drawn off of the carbon in
the EVAP canister are consumed in the engine.

Fig. 68: Identifying EVAP System Components (Focus & ZX2)

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Theory & Operation - CNG, Flex-Fuel & Gasoline