I'm Sick of Smelling Gas

[grizzfan]

Gasoline fumes occur during cornering, driving straight and getting in the cab. I've changed out the gas cap gasket, as was suggested some years ago, to little avail.

I need (please) some comprehensive suggestions on how to beat this. I suspect there are some old hoses leaking somewhere, although I see no evidence of leaking.
I've examined the hoses in the frunk and, while they look yellow and frunky, I see nothing leaking. Should I choose to "replace everything" where do I go for a set of parts and a strategy?

I've searched and I come up with gas cap gaskets!!

Some Pelican out there know how to do this!

Happy Memorial Day Weekend. Remember our fallen.

Best,

Tom

[porsche930dude]

what year? Is youre charcoal canister in good shape and the system all in place. Might be wize to open up the canister and see if there is anything left in it. The lines could be leaking in the tunnel that is fairly common

[Rusty 356]

Remove the left gage and check the black plastic canister for possible cracks.
hoses to and from same.
Early 911

[RSTarga]

What year car? Check all your fuel lines. Don't open the canister, just check that all lines including the ones going to the above mentioned breather is not cracked or tipped over.

[tkmoore]

Grizfan,

I have been struggling with the same lingering fuel smell in my 83 sc and can't figure it out either. I can find no hard lines leaking, I've replaced gas cap, fuel sender gasket, and just a few weeks ago replaced the carbon canister and every fuel vapor line both front and rear. In replacing all those non-pressure vapor lines I went online a googled the Porsche PET for my year and it lists part numbers and metric sizes for about every fuel line and vapor hose. Pelican sells all the hard lines and most vapor hoses but I found some NLA and 14mm hose about impossible to find local here in Denver.

In replacing all the vapor lines I just took the PET metric sizes and lengths, converted them to very near USA sizes in E85 rated fuel hose available at NAPA. My hose list consisted of 15' of 5/32, 6' of 1/2, 3' of 9/16 in lieu of the 14mm, and 3' of 3/8. Most of the new hoses fit well and I used mostly new hose clamps.

The Porsche PET also has a hose diagram to aid in seeing how they are routed. I'm glad I did them all; just wish I'd solved my fuel odor. Good luck and let us know if you figure it out. 😄

[Bob Kontak]

Originally Posted by porsche930dude

what year? Is youre charcoal canister in good shape and the system all in place. Might be wize to open up the canister and see if there is anything left in it. The lines could be leaking in the tunnel that is fairly common

I would pass on the canister inspection for the moment only because I don't have mine in the car and I smell no fumes. (1981 with the canister in the engine bay).

Given it's a sealed system and the "in" is the gas tank and the "out" is the air box. why not plug the gas tank "in" port with a nail and blow on the hose that feeds the airbox. See if pressure builds.

If not, disconnect hose under the car (drivers side, left of center, near where the tunnel ends.) Repeat test to isolate. Etc.

I have to think you can fiddle with it a bit to narrow down where the system is leaking. Front end is more suspect than rear.

Maybe the fender expansion tank is cracked?

I think the tunnel is a metal tube rather than a hose?

Edit: Looked at some of OP's other posts and he has a 73. I think the canister is in the front but not sure.

[RSBob]

Many of the hoses shrink over the years. Try tightening all the connections. It is surprising how loose they can become. I also changed the gasket to the fuel sender and that helped the most.

[RocketMan27]

I had a similar issue, the cabin and front trunk always had a petrol smell. I replaced all the vapour lines between the fuel tank, expansion tank (in the front left wheel well) and carbon canister in the rear. This seemed to pretty much fix the issue for me, was impossible to know where the problem was exactly. This includes the line that connected in from the expansion tank to the hard line down the centre tunnel just forward of the gear stick.

I did also notice another issue that may have been a contributing factor. There is a T connector in the front trunk that goes from the fuel tank to the expansion tank and then vents at the fuel filler. I found that if I overfilled my fuel tank my expansion tank would fill with petrol via this connector. I fixed this by moving the T connector as far up the line towards the fuel filler as it would go.

Not sure that opening the carbon canister would be fruitful, I would say so long as it looks ok and feels full then its ok.

[grizzfan]

Thanks for all the suggestions so far! Several have asked. My engine is a '75 911S or Carrera (same USA specs that year) 2.7L and the body is a '73 911T.

I'll digest your suggestions and see what I can see. One poster, tkmoore, came closest to suggestion a complete hose replacement and that is a possibility for me. Need to study that more.

Seems to me that someone on this board fabricates a complete replacement fuel line system. Or was that for a wire harness? All things seem to run together these days!!!

Best,

Tom

[azhodge]

If you have not already done so, put a fire extinguisher in the car before you drive another mile. Lots of threads on what to get.

[Bob Kontak]

Originally Posted by RSBob

I also changed the gasket to the fuel sender and that helped the most.

Very good point.

Makes me wonder what if the expansion system is clogged? Vapors will find a way out.

I am sensing some grunt work in OP's future to nail this. Easy work but a time soak.

[wildthing]

Mine starts to smell when I don't drive it for more than two weeks and then I drive it.

Needs more driving than sitting.

[Ronnie's.930]

Based on the thread title, I thought you were talking about something along the lines of . . .

[joefrantz]

Tom

Check out the link below. It is a good discussion of all of the components in the vapor recovery system that would have been on your car originally. There are a lot of others, but this one is a good starting point.

Take an inventory of what you've actually got.

Assuming you've got the components, I would start with the under dash cube first, and make sure it is not leaking. I think the referenced thread mentions that most of these crack around the bulls eye in the bottom.

Next replace the "clear" vent hoses that connect the tank, the under dash cube, the filler overflow and the fender tank. Don't bother trying to tighten the clamps. If the hoses have turned that familiar brownish color, they will be too stiff. You will need to carefully remove the clamps and the "Y" fittings and save the old hoses to use as templates for the new ones. Be careful with the "Y" fittings. They will be very brittle, and I'm pretty sure they are NLA. The specs for the replacement tubing is in the thread. Also save and re-use the clamps if possible. They don't make 'em like that any more.

There is a good chance that these two steps will solve the problem. I've been told that the old type canisters are pretty much good forever. It is possible that the braided lines between the canister and the engine are shot, but I would wait to do anything with those until you've done the above.

Good luck.

Need a little trunk help...

[joefrantz]

Originally Posted by grizzfan

Seems to me that someone on this board fabricates a complete replacement fuel line system. Or was that for a wire harness? All things seem to run together these days!!!

Best,

Tom

Sorry, didn't see this earlier.

Len at autosportengineering dot com is the man for CIS hoses.
He goes by BoxsterGT on here. You will need to email him rather than PM.

Definitely a good idea to change out your fuel hoses if you don't know how old they are.

[craigmakes3]

Just went through this with my '81. It stunk all the time, but particularly after hard cornering. Turns out the lines to and from the expansion tank were all cracked and leaking. Sometimes they were actually wet from fuel, most times the fumes just escaped them. Cannot see the cracks, because the lines are fabric covered. Also replaced the connection hose from the tank to the filler neck while I was at it.

[mikesride]

Originally Posted by craigmakes3

Just went through this with my '81. It stunk all the time, but particularly after hard cornering. Turns out the lines to and from the expansion tank were all cracked and leaking. Sometimes they were actually wet from fuel, most times the fumes just escaped them. Cannot see the cracks, because the lines are fabric covered. Also replaced the connection hose from the tank to the filler neck while I was at it.

Same thing here with my 82.

[911SauCy]

Think yours is annoying.

I redid the entirety of my fuel lines with AN Braided goodies a couple years back.

After driving the car and letting it sit in the garage, the fumes accumulate and smell horrendous. I wish I was aware of this prior to making the conversion as I'd have not considered had I known.

Supposedly it's because the ethanol seeps, on the most minute level, through the lines and evaporates.

It's only bad after fuel has been running through them, parked all winter, there was no smell.

[Targa Me]

I had the same gas smell in my '84 3.2

It turned out to be a pin-hole right where the filler neck and tank meet.

[boxster03]

it was my fuel pump that was leaking - checked it last and not until it was leaking on the floor - close call