Component Testing - Ford Ranger Maintaince And Repair Manual

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as well as, the fuel tank and fuel tank filler pipe, vapor tube and fuel vapor hoses.
Fuel Vapor (Charcoal) Canister
The fuel vapor canister is referred to as the evaporative emissions canister on 1441−44 models.
The fuel vapors from the fuel tank are stored in the fuel vapor canister until the vehicle is operated, at which
time, the vapors will purge from the canister into the engine for consumption. The fuel vapor canister contains
activated carbon, which absorbs the fuel vapor. The canister is located in the engine compartment or along the
frame rail.
Orificed Vapor Valve
This component is also known as the evaporative emission valve on 1441−44 models.
Fuel vapor in the fuel tank is vented to the carbon canister through the vapor valve assembly. The valve is
mounted in a rubber grommet at a central location in the upper surface of the fuel tank. A vapor space
between the fuel level and the tank upper surface is combined with a small orifice and float shut−off valve in
the vapor valve assembly to prevent liquid fuel from passing to the carbon canister. The vapor space also
allows for thermal expansion of the fuel.
CANP Solenoid
The CANP solenoid is inline with the carbon canister and controls the flow of fuel vapors out of the canister.
It is normally closed. When the engine is shut OFF, the vapors from the fuel tank flow into the canister. After
the engine is started, the solenoid is engaged and opens, purging the vapors into the engine. With the solenoid
open, vapors from the fuel tank are routed directly into the engine.
Pressure/Vacuum Relief Fuel Tank Filler Cap
The fuel cap contains an integral pressure and vacuum relief valve. The vacuum valve acts to allow air into
the fuel tank to replace the fuel as it is used, while preventing vapors from escaping the tank through the
atmosphere. The vacuum relief valve opens after a vacuum of −0.21 psi (1.2 kPa). The pressure valve acts as a
backup pressure relief valve in the event the normal venting system is overcome by excessive generation of
internal pressure or restriction of the normal venting system. The pressure relief is 2 psi (14 kPa). Fill cap
damage or contamination that stops the pressure vacuum valve from working may result in deformation of the
fuel tank.

COMPONENT TESTING

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