[rmn]

I just had a mate onto me about a problem he is having
he got to work today and noticed a trail of fuel out of his car.
the fuel was being forced up the filler neck.
when he opened the tank it was pressurised and made a huge amount of noise
he started it again with the cap off to see if it was now better but it wasnt as the fuel started to come out the neck.
Anyone have any ideas?
To me it sounds like a blocked fuel tank breater, but how does this work on a mk4 gti?
Thanks

 

[johnny99]

All fumes from the tank are vented into a charcol cannister under the bonnet, which looks like a black cannister with two pipes coming out of the top of it. One comes from the tank and the other to the inlet manifold. These fumes are then sucked into the inlet manifold when the car is running and the solenoid is activated. there should be a vacum from the tank when the cap is removed. This is called the EVAP system, and is on all cars since the mid ninties. Your mate seems to have a problem with this system.

If you let me know the engine code, I can look it up an ETKA and see the layout, and possible causes.

John

 

[rmn]

Cheers John we got it sorted, it was a problem with the carbon canister
Thanks

 

[johnny99]

Thought so, same as above. What was the actual problem, as these are fairly rare.

John

 

[MkIV GTi]

QUOTE (johnny99 @ Feb 15 2006, 11:13 PM) <{POST_SNAPBACK}>All fumes from the tank are vented into a charcol cannister under the bonnet, which looks like a black cannister with two pipes coming out of the top of it. One comes from the tank and the other to the inlet manifold. These fumes are then sucked into the inlet manifold when the car is running and the solenoid is activated. there should be a vacum from the tank when the cap is removed. This is called the EVAP system, and is on all cars since the mid ninties. Your mate seems to have a problem with this system.
If you let me know the engine code, I can look it up an ETKA and see the layout, and possible causes.

John

Hi John,
I'm the owner this '02 VW GTi whose tank was leaking petrol. What ended up happening was that after I got the car home that night I removed the petrol cap and realeased any pressure that had built up, I then heard a large amount air bubbles being released from within the tank. Since then I haven't had a problem with it. So there was obviously some sort of air blockage, do you know where it might have been?

Thanks,
Gary

 

[johnny99]

Sounds like fuel was trapped in the vent pipe. This is the pipe that runs parallel to the filler to let air out when you are filling the tank. Can happen sometimes and is nothing to worry about.

John