Tony

87 S4 auto..
Im pretty sure i know the answer already...but i assume the tank has to be completely dropped to gain acces to and replaces this vent line? Any BTDT's?..better yet pictures that show it?

I have a gas vapor smell, and have had it for a while...time to get rid of it. Im assuming it is this line right now.


The other lines are accessed via the rear wheel arch if I recall, so they will be easy to check...replace if need be.

Is it common for this cross over vent line to fail/break? Its under no pressure or stress as far as i can see in the drawings and where it sits in the system? It just allows the tank halves to be completely filled.

Herman K

Have you checked that all your hose connections at the carbon canister are tight and none of the hose in that area are cracked?

If not do it first before you drop the tank

Tony

Canister is tight as a drum..no leaks there. The smell IS from the back. Defintiely. No visible fuel leaks either.

Mrmerlin

did you look at the sender area maybe the sender nut is a bit loose.
If your going to drop the tank I would also have on hand some flamemaster sealant its for sealing jet wing tanks and will also work on your tank, may also be called proseal its a 2 part flexible adhesive that jet fuel resistant. found at your FBO parts store near most major airports
I would suspect the fittings that come out of the tank

m750rider

Before dropping the tank, check the sender area on top. If it leaks slightly, you will get an in car gas smell with no apparent leaks from the tank. The gas that does leak will pool in a recess around the sender nut. The smell will be strongest when you first fill the tank. Tighten the nut, and/or replace the seal underneath it.

Leon Speed

Big Dave has a write up on his site, I think Dwayne too, Rob Edwards has a thread with pics as well.

FLYVMO

Tony,

Check hose #23, it is under the car, slightly behind the center of the car. It splits the hard line fuel vent in two pieces. Mine was letting fuel smells out and made it seem the smell came from the rear. Only found it after already spending money on a new canister, thinking it was bad...

Cheers!
Carl
90GT shell

Lizard928

The tank must be dropped, and this hose goes THROUGH the frame.....
You have to undo it from the filler neck side and feed it through the body.

Most cars I have seen this hose has been in poor condition.

PorKen

Tony - in your pic (24) dumps behind the center of the rear bumper (from '85, has a rubber bellmouth). There will be some fuel vapors, there. But it sounds like you have a stronger smell.




FYI - up until '87 ROW cars w/o the carbon cannister just dump straight there. '84 and earlier USA dump into the airbox.