Gasoline fumes are coming throug ventilation

[MattP]

Hi folks

Just got the Urs4 our of winter sleep and first time you start that thing you need to get out or the fuel fumes get you!
While driving is keeps coming through the ventilation, when you cut the ventilation it's almost zero. When somebody gets in the car first thing they say is that they smell gasoline.

Before the winter sleep i had the same problem, but if you ask me it worse in following scenario's
Fuel tank is FULL
And outside it's cold if you start then the first 2min you need to open all doors.

Where should i start looking?
Fuel tank itself in the trunk?
But it comes from the ventilation so i would guess for something under the hood?
Last year we checked but we could not really find any leaks.

For a check i threw a bucket of water over the front window and i could see gasoline or oil in the water.

[Avantus]

fuel lines would be my guess

[MattP]

fuel lines would be my guess

If the car is on the lift and we follow the lines we don't see anything special or a leak.

Where can fuel and ventilation come together?

[jsol]

Check the tank breathers/charcoal canister system.

[UrS4boy]

C4 UrS Fuel System: From the Tank to Injectors and Back Again

Where can fuel and ventilation come together?

Umm... the air intake for the ventilation system is just below the raintray, just underneath where I have labled [C4 UrS Fuel Lines Near Fuel Filter] in the red box. Do you still have braided stainless steel lines leading to/from the fuel filter?

C4 UrS Fuel System: From the Tank to Injectors and Back Again

http://forums.quattroworld.com/s4s6/msgs/226410.phtml

The air enters the ventilation system through the flap at the back of the evaporator box

[sidrick]

PCV pipework.

[220bhp]

My S6 leaked from the braided line feed into the fuel filter.
I was told by Audi that it was a common failure

[UrS4boy]

My S6 leaked from the braided line feed into the fuel filter.
I was told by Audi that it was a common failure

Correct. It was so common that by 1999 in North America there was a US DOT and Canadian Transport Canada recall that required Audi to fix the problem. My car was like the 2nd car in Canada to be done. They replaced the leaking braded fuel lines with solid metal (the ones that show in my annotated photo). Mine involved completely new (UrS6 non-braided fuel lines, requiring that the steering rack be moved away from the firewall (naturally the dealer screwed that up and I never went back there again). Later in the recall campaign "KY" (jokes mandatory), they figured out that they could cut away the braided bit and replace it with metal without moving the steering rack. Always nice to be the guinea pig (NOT).

[MattP]

It was a little flexible that caused the fumes.
Garage replaced it and now no more fumes.

[Greg_S]

Do you know which one caused the issue?

[UrS4boy]

One of the braided hoses

Here is some documentation from around 1998-9:

http://web.archive.org/web/20030302143045/http://urs4.com/technical/miscellaneous/fuel_leak/fuel_leak.html#feuer