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Old Mar 12th, 2017, 20:28   #8
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Last Online: Apr 11th, 2020 18:06
Join Date: Feb 2017
Location: Nijmegen, Netherlands

Originally Posted by Clan View Post
when idling you can hear it turning on and off , pulsing , the air going through the canister from the tank should evaporate any fuel off if it is working .
Are you sure? I thought the solenoid valve is closed when idling. It only opens when driving. This is from a Dutch forum:


EVAP is the EVAPorative control system which processes the petrol vapour in the fuel tank. These gases harm the environment.
The car has a canister with a carbon filter which can absorb a large quantity of petrol vapour while the vehicle is standing in the sun (when a lot of fuel evaporates). The vapour is then introduced into the combustion process during driving.
To control this process there is a solenoid valve mounted on the canister which is operated by the engine control module (ECM).
While the car is stationary the valve is closed, but there is a connection to the fuel tank.
When the car is being driven the valve opens when engine coolant temperature (ECT) exceeds +60C and the intake air temperature (IAT) exceeds −10C. A connection is then made with the engine intake manifold. The valve is operated by an 8 Hz pulsed signal.
While the canister is open the injection times are adjusted with the heated oxygen sensor (HO2S) providing feedback. The system is adaptive, so that the canister can be completely purged. Even at wide open throttle (WOT) (oxygen sensor not working) the system remains in operation.
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