Gas Fumes Coming from Tunnel

[chris belyea]

I was hoping someone out there may have some thoughts as to where the smell of gas is coming from in the cabin of my 1970 911E. The other day, after filling up, I started to smell gas inside the cabin. I’ve looked and felt around the car and cannot see or feel any leaks what so ever. I had some work to do on the pedal cluster and that’s when I noticed the smell got stronger. I jacked the car up and inspected the fuel pump and lines and everything looks good. I pulled to carpet up at the front of the tunnel and at the back at the shift linkage and that’s where the smell is coming from. I know the steel fuel lines are running through the tunnel but it seems unlikely they would have a hole in it.

Anyone have any thoughts? It’s probably something simple but after a week, the smell is still coming from the tunnel.

Regards

Chris

[GaryR]

If it was right after a fill I would suspect the overflow but after a week AND you say it's coming from the tunnel I would be worried about a seeping fuel line inside it, and that's a baaaaad thing. You may want to pop the shifter off to gain access to the front section if you can't see anything through the coupler port or on either end.

[Rot 911]

What Gary said. Ventilate well so any spark doesn't create an explosion.

[DaddyGlenn]

Originally Posted by chris belyea

{snip}.... I know the steel fuel lines are running through the tunnel but it seems unlikely they would have a hole in it.

Anyone have any thoughts? It’s probably something simple but after a week, the smell is still coming from the tunnel.

Regards

Chris

I wouldn't be too quick to dismiss a leaking fuel line. Steel doesn't last forever and if those lines are original, they are over 40 years old.

[kugelfischer]

I'll second what Glenn said. My own lines were replaced when the car was about 30 years old.
I've also recently read where someone used seat rail hex bolts that were too long and punctured their hard line. Apparently it runs under the seat rail attachment area.

I'd probably think about replacing the line to be safe.

[chris belyea]

I may have a leak in the hose. I've been restoring the car for the past year and I did remove and reinstall the seats. Perhaps I damaged them like you said. What needs to be removed to replace them? Engine or fuel pump and tank?

[19-911-65]

I just replaced mine in a '66 with SS lines from the back, the engine is out and its a pretty straight forward swap. At least in mine...the lines go tight up against the drivers side of the tunnel...behind a brace for the seat rails.

[DRACO A5OG]

check the engine bay too, the other day saw a fella with an older 911 and his fuel was leaking because the non oem clamp he used tore into to the line.

[Porboynz]

Originally Posted by chris belyea

I may have a leak in the hose. I've been restoring the car for the past year and I did remove and reinstall the seats. Perhaps I damaged them like you said. What needs to be removed to replace them? Engine or fuel pump and tank?

Been there done that, check my thread: Its Alive!!

Pull the drivers seat and inspect your fuel line through the bolt holes with a fuel vapour safe light source. The fuel line can be replaced with the engine and fuel tank in position, but its a PITA job. Its also really annoying once you realise what you have done. (maybe fitted bolts that are too long, or like me tapped the threads out)

[p911dad]

Chris, if you filled to the very top, maybe that could be the cause of the gas smell. However, our 84' had a similar issue with the gas smell, and it turned out to be the short flexible fuel hose that connects the fuel tank with the hard plastic fuel line that travels back through the tunnel to the rear, where there is a connection to another short fuel hose leading to the fuel filter by the engine. In out case, the line coming out of the tank had a small crack. This line assembly is all one piece from the tank back to the rear bulkhead.
If the line is cracked or split, the proper and safe fix is to pull the lines and replace. It is possible to have the short hose made up, but then you have connection issues. I used the oem parts available here (there is a fuel line and a return line) from our host. It is not an "easy" job, but certainly not impossible for an owner to do. You can use the search function for much more information on this project.

[E Sully]

Gas smell by the pedal cluster could also be the fuel tanks vaopor lines. They run behind the pedal cluster and connect by the front of the tunnel. I had to replace the hoses on my 1973.

[chris belyea]

I filled the tank up again this weekend and the gas smell is strongest after a fill up. I cannot find any leaks around the fuel pump or supply lines. I haven't ruled out that the steel lines aren't damaged but I don't notice the smell has much when I had a half a tank. I would think that I had a leak in the supply lines, the smell would be strong once the fuel pump kicks on. That doesn't appear to be the case.

One thought that I have is that there is a 1/2" hose coming out of the top of the tank. This might have been for emissions at one time but is not longer hooked up as it came from the factor. I believe is run back the the air box now as a vent. My thought is that when if fill up completely, there is gas in the filler neck. Since the level of gas would be higher in the neck than the top of the tank, I'm guessing that the gas is getting in that line and that is causing the smell. I just need to find where that line runs.

Chris