fuel smell

[cfassett]

I have started addressing a couple of issues on the 951. The first of these was ye ole exhaust smell when the windows are down. Took care of this by sealing the drain holes behind the fenders and under the spare. It started with the install of a 3" Lindsey Exhaust. Don't know if the new exhaust changed the flow of exhaust fumes, or if it's juts coincidence, but for the sake of others fighting this issue, for me plugging those body drain holes did the trick!

So in the spirit of 951 ownership, its on to the next issue!

There is a slight fuel smell, again when the windows are down, when the tank is full. Possibly stronger on hard acceleration. I have replaced the seal under the fuel level sender, and today pulled the metal cover off of the vent hose section (behind rear passenger seat). No obvious evidence of any leaks under there, though the hoses are old.



I filled it up completely and took it for a brief spin around some corners and such. Still no evidence of leaks in the vent hoses under the cover.

I did however, find this evidence of some sort of leak on the passenger rear side of the gas tank. I don't know what is up in that area. Could there be a drain hose up there of some sort, or possibly a crack in the tank?

[cfassett]

Pics...


And the possible leak evidence...

Sorry. Yes it is upside down in the pic

[Fast Freddy 944]

If you think thats bad, try to find one in a Jaguar! lol, I had a horrid fuel smell in a 86 xj-6, That car had jubilee clamps for each fuel injector and they were pooling up fuel on the manifold. not good. I had a 87 camaro with the same issues, took it to a dealer wasted moneys and had the same smell. My xj was a bloody nightmare but I got the good smells back. the camaro was easy, the charcoal can was relplaced and hoses were refreshed. I have an 86 951 and I did my charcoal cannister and I checked everything fuel related and its good to go. Just keep at it and you will find the trouble...

[cfassett]

Thanks Freddy! I decided to leave it all uncovered, to see what I could see.

Today we have a little gas puddle around the fuel level sender area. I just replaced that gasket last year, but may need to redo it. Hopefully that is the issue here. I layered some paper under the hoses and such to see if one of those happens to be leaking.

[kdjones2000]

There is an expansion tank "reserve" thing up in the body above the fuel fill area, with hoses attached to that. That could be another source of fuel smells.

That being said, re-tightening that fuel sender enough can be VERY hard to do without a special tool. I am still fighting smells/leaks at the sender after 10+ years - just haven't made up a tool, and channel locks are just not good enough to do the job right.

[Fast Freddy 944]

Originally Posted by cfassett

Thanks Freddy! I decided to leave it all uncovered, to see what I could see.

Today we have a little gas puddle around the fuel level sender area. I just replaced that gasket last year, but may need to redo it. Hopefully that is the issue here. I layered some paper under the hoses and such to see if one of those happens to be leaking.

Fuel puddlin' up? Yeup that will leave a strong odor and fuel vapors, very dangerous. If something is over my "head" I wont take a second thought about taking my car to a Porsche repair shop. Luckilly I have Zims near by. Good luck. Yeup there is always a "special tool" for any super car like the one's we own..

[cfassett]

I didn’t realize that cap was supposed to be on any more than hand tight. How tight is it supposed to be?

[Fast Freddy 944]

Originally Posted by cfassett

I didn’t realize that cap was supposed to be on any more than hand tight. How tight is it supposed to be?

I learned of two types of fuel hoses in Aviation Engine training in ground school. Low pressure and high press fuel lines and systems. Low pressure systems are found on carburated recips and high pressure fuel systems require tighter fitting hoses, clamps, seals, etc, as fitted on fuel injected recips-and jets. MG.s use low fitted clamps on their fuel lines with jubilee clamps tightened to the carbs, filters, pumps, etc. The lines and connectors on our porsches are high pressure fittings, with special clamps, o-rings, and fittings. These cars like all fuel injected may need a special tool, fresh parts, and yes some torque may be required to stop the leaking. You might consider taking it up to a german car shop and have em snug it up for you. They can solve it.

[Mike Goebel]

If you're really unlucky, like I was, the filler tube where the it intersects the tank could have broken off. I did a hack job on that using a combo of JB weld plastic epoxy and fiberglass matt. Later I read that the material for the tank is polypropylene and that crazy glue would have been better. I think???

Mike G.

[kdjones2000]

[cfassett]

Thank you! I found a way to get some more muscle on the cap, and it did stop the issue I was having.

[nize]

cfassett what did you use for special tool 9190 ?

[cfassett]

A modified oil filter wrench. Needs some work, but it at least got it tighter than my fingers could do it.