gman1868

My 944S2 has fuel leaking out the cap area during track sessions. I've replaced the cap, but it still does it.

I've taken the internal cover off where the filler tube (and several others) are located and there isn't any physical damage to the hoses.

Any ideas what to test to determine what is bad, e.g Check Valve, Evaporator, etc?

Have any of you experienced this problem? TIA!

H2

Bump...
'
no idea. Sorry. Will be interesting to find out the answer though.

Harvey

shiners780

I had this happen as well, but replacing the cap solved the issue. Sorry, that's all I've got.

Mighty Shilling

does your fuel fill nozzle have any funky dents around the rim that would cause the cap to not seal properly? both the 924S and TurboS had this problem...and a gas cap fixed both of em.

shiners780

Good point! The rim shape can get distorted from people leaning on the gas pump nozzle when filling up making it out-of-round.

An old wives tale is to spray the gas cap gasket with WD40 to make it "plump up" and seal better. Didn't work for me, but ya never know?

gman1868

Well, I pulled off the hoses around the filer area and none of them are plugged. I also chaked the roll-over valvle which seems to close when upside down (well, I could squeek a little air by when I blew on it real hard).

I also checked the rim of the filler to see if it was flat and it is. At the shop we removed one hose and pressurized the gas tank with some compressed air and I could hear a slight air leak at the cap.

I think I'll go to the dealer on Monday and buy a new OEM gas cap. THe stylin FRAM that I bought also leaked a littel air too, even though I could get it tighter on the filler than the original OEM cap.

Thank you all for your help, if you've got any better ideas I'd sure appreciate it.

(Can't forget a roll of butyl tape for the cover either...)

Mighty Shilling

One tip I've found, if you save it ONLY for track days, is get a 993 gas cap. they fit just fine, and have a tighter seals... However, if you use it for daily duty, after a while, the tighter seal will cause the cap to wear quicker, and it'll eventually break... resulting in the cap no longer working, and being stuck in your fill nozzle... I know this one from experience... it can be removed without drilling it... just have to destroy the cap. Keep the 944 cap for DD use, put the 993 cap on for track duty. new caps IIRC run about $24.00, so they're not that expensive. best of luck!

gman1868

Welp, I replaced the cap with a 993 gas cap, and it still leaked at the track. I found this answer on the pca web site, but now I'm going to be hard-pressed to find somewhere that has fixed this problem before.

"The fuel tank on the 944 is a completely sealed system, so if raw fuel is leaking out, you've got a diagnostic challenge.

Porsche originally considered the fuel cap seal replacement as part of the scheduled maintenance on 944 models. If you haven't changed it lately (not the cap, the seal on the cap) then give it a shot. If that's tight, have a qualified Porsche repair facility use a CO% meter to check for hydrocarbon leaks around the filler neck itself.

Bill Burris - PCA WebSite - 10/10/2005"

Any other ideas? The fuel is ruining my paint

Rob S

Reviving an old thread here. I have exactly the same problem as gman 1868 had -- my 89 S2 leaks fuel from the filler area (onto the paint) during left hand turns on the track. It doesn't leak on the street. I replaced the cap last fall with a new factory cap. Just last month I had a smog check, and my new cap passed the pressure test, so I'm guessing it's fine. The rim around the filler looks to be smooth and round, though I haven't pulled it out to really examine it. To top it off, I've seen two other 944s of my vintage leaking fuel from this area, and the owners don't know why.

Has anyone got any new ideas on this? I've really got to fix this...

Thanks,

Rob

Rob S

Help! Does anyone have any ideas here? I know of 3 944 S2s or turbos that have this problem. Does anyone have any ideas? If I know of three problem cars, surely this has happened to others on the list.

Rob