Urgent help needed turbo S race car fuel smell in cockpit
 

We are running my 89 Turbo S race car and are getting a strong fuel smell in the cockpit in Left hand turns. The tank has been replaced and doesn't leak. The fuel filler neck and the cap have been replaced and don't leak. There are 3 hoses on the filler neck I would like to know which ones I can plug to try to diagnose/eliminate the problem.

One goes to the expansion tank, which in turn goes forward to the charcoal canister. I don't know where the other two go.

What's involved in eliminating the line to the expansion tank?

Where do the other two go and can I plug them?

I would appreciate answers tonight, since we have 2 races tomorrow and one on Sunday.

John,
This is a longshot but you mentin the charcoal canister so I'm going to assume you still have the evap system in tact. Check the plastic diaphragm under the hood that is located on the driver side by the brake booster. If it does not hold vacuum it is probably punctured and under boost it will allow manifold positive pressure to leak thru and pressurize the fuel tank. There is a hose that goes from the top of the tank to the atmosphere that runs along the side of the tank between the tank and the frame rail that you can see when you look from under the car. This is where the smell will be coming from as long as everything else sealed properly. If this is the case you can plug up the vacuum line to the diaphragm to get you thru the weekend. It's worth a shot to check.

Thanks, I'll check but it seems to be turn related and coming from the back. I really have no need for the evap system. How can I eliminate it?

Is the expansion tank located in the Pass, side C pillar?

https://rennlist.com/forums/924-931-...m-removal.html

Post 21 has a picture.

If the fuel drain off of the filler neck area doesn't go all the way out the bottom you get smell in the car, you will find fuel behind the fender inside the car, or at least signs of it from paint discoloration.

If the fuel expansion tank in the pillar above the filler neck is leaking the fuel will run down the front of the fender into the back seat.

Could be poopy pants. Long shot, but should be considered.

Please keep us posted on what you find.

Is there any fuel staining on the right fender near the fuel filler?

There was some staining on the inside of the fender, but the fuel cap was leaking. It is now fixed.

I'd give the collar on the top of the tank a tap to make sure it's tight. IIRC One of the tubes is a vent and one is the return line. Plugging either one is going to lead to issues. Also are you sure you don't have a fuel rail that is leaking under high pressure and not at idle? They are notorious for pin hole leaks and cracks.

It's usually right around the cap or the top of the filler. So is it fixed now?

Any news?

Talk to your friendly local mechanic about this issue. Mention Michel G. at Texas World Speedway.
Sounds like the same issue.

Thanks for the additional input. We temporarily "solved" the problem by installing a long upwardly looped line from the filler tube vent to the outside of the car and two NACA ducts and hoses to bring more air into the cockpit. Still not sure its actually fixed.