I was working on the my car today and had it idleing for long enough to get up to temp. When I shut it off I heard a huming sound coming from around the charcoal canister. It seemed to be the small valve thing that is in one of the lines right before the canister. I held it and it was vibrating so I assume it was just some weird occurance that was causing it to hum. Also, the charcoal canister was venting out of the port marked "Air". The stuff coming out didn't smell strongly of gas. Is this how it normally opperates or is it just venting my gas away??

 

What you heard is probably completely normal. The EVAP canister also has a tank pressure control valve on it. After running the engine for a while, the exhaust heat likely warmed up the tank and fuel, causing faster evaporation and higher tank pressure. Although you couldn't hear it with the engine running, the pressure control valve had probably been relieving tank pressure the whole time. It just continued to do so after the engine was shut off, and would continue to do so until the tank pressure was back to normal.

 

Ah, good to see its working well.

Thanks

 

Vader,

The line leading to my charcoal cannister has drops of fuel coming out of it into the cannister. After the car is warmed up especially on warm days, the car smells like gas and the vapors are very strong at the vent tube for the cannister. I have already replaced the in-line valve to the cannister but still have the same problem. What would be causing the drops of gas to come all the way from the fuel tank? Do I need to remove the tank and check the line or is there a check valve that should stop this from happening? Thanks for any help.