Fuel Tank Cap ? Strong fuel smell?

[Slider]

I've been driving my Mark IV with Coyote for almost 2 years. Everything has been going well. Yesterday I went and filled up (to about 3/4 full) and when I went to put the plastic gas cap back on, it wouldn't tighten very well, and when it did, it was difficult to take off. I figured I'd take a better look today. however, after having the car sit in the garage all night I found a very strong Gas odor when I entered this morning. I checked all the fuel lines as well as felt for leaking fuel everywhere I could think, and found no indications of a leak. However, the fuel pressure was down to zero and it normally holds pressure better longer than that.

So my question is, could a loose fitting fuel tank cap allow that much odor to escape? The Lemans type lid was still closed, and the fuel smell was really strong.

Second, can anyone tell me what type of car the plastic gas cap is off of so I can find a new one?

Finally, if anyone else has any other thoughts on this, please let me know.

[68GT500MAN]

Yes you could get that much smell from a bad cap. Go to your favorite auto parts store and buy one that fits a Ford Mustang.
Doug

[Slider]

So, new gas cap which seals tight, but still a strong fuel smell this morning. As Indicated, I've checked all the fittings, the fuel filter, etc and can find no leaks, or signs of leaks. Does anyone have any ideas on how best to identify where the smell (and probable leak) is coming from? When I get under the car, the smell seems to be strongest up under the fender where the fuel filler is, but again, I can see no indication of a leak, and even when reaching up around the connections at the tank, everything seems to be as it should be... Ideas are appreciated.

[Timb]

Do you have a vent line running up there? Are you using a charcoal canister?

[Slider]

No charcoal canister, but haven't had one for almost 2 years and never an issue before. I mean I've NEVER smelled any gas at all, so to go from nothing to this strong overnight makes me think there must be a leak somewhere...

[Slider]

So, after getting the car out of hibernation I found the source of the gas smell... The grommet/gasket around the fuel tank filler pipe (where it enters the tank) is leaking. Everytime I make a left hand turn, it spills fuel out. Not sure how this came loose, but hoping that I can just remove the bracket, push the grommet/gasket back into place and it will be resolved.

Has anyone else had this issue? Any ideas on how to fix it so it doesn't come loose again?

[Avalanche325]

So, after getting the car out of hibernation I found the source of the gas smell... The grommet/gasket around the fuel tank filler pipe (where it enters the tank) is leaking. Everytime I make a left hand turn, it spills fuel out. Not sure how this came loose, but hoping that I can just remove the bracket, push the grommet/gasket back into place and it will be resolved.

Has anyone else had this issue? Any ideas on how to fix it so it doesn't come loose again?

Yes, it is pretty common for them to leak. My brand new one that came with the tank did. I got one from NAPA, which according to some forum members is a better one. No problems since.

[rich grsc]

It must have been installed incorrectly or was damaged when installed. Get a new one, lube it with engine oil when you install it. Once installed correctly, with the fill tube in place its almost impossible to get out.

[Slider]

When I got the grommet out it was torn. So probably did so at install, though it ran for 2 years without a leak so probably just got worse over time. So I've got a new grommet installed, but am fighting like crazy to get the fill pipe through the grommet as I don't want to tear it again. I've lubed the pipe with a bit of oil, but it's not budging. I've dropped the tank a bit to get more room, but still no luck. Any ideas? Should I do something to taper the end of the fill pipe so it starts easier?

[DaleG]

Use Moly-lube with graphite; comes in a tube.41703

[Slider]

I ended up cutting 1.5" slots in the end of the fill pipe so I could taper it slightly... Worked like a charm! (used STP to lubricate the grommet). Fixed and tested! No more leak!