Gas spilled out of filler cap onto fender during hard left turn - YIKES!

[AdamIsAdam]

I auto-x'd my FFR for the first time. the course had one big 180* left hand turn on it. When I took my first mellow run to warm the tires, no problem. On the second and every subsequent run, on that turn gas came out of the cap and spilled down the fender. I had 3/4 of a tank. I know it was that turn because I first smelled it moments after that turn.

Is the cap bad? Is there a vent that's misbehaving? 20201108_133334.jpg

[Sdonnel]

First question that comes to mind is whether you have the modern day plastic cap inside the LeMans cover? If so, I don't see how the fuel would push past that cap unless it were not ratcheted down. The holes in the flange are for overflow when filling the tank and not an escape source for sloshing fuel (I could be wrong). How long of a vent line do you have on the tank vent? I made mine nice and long to a home made charcoal cannister.

Scott

[AdamIsAdam]

Yup, modern cap. See pics of cap and vent line:

20201109_175659_HDR.jpg

20201109_175551_HDR.jpg

[Papa]

I had problems with the cap that came with the kit not properly sealing. I found it just sitting loose in the filler several times. I replaced it with this cap:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

No more issues.

[AdamIsAdam]

DONE.

Gotta love forums! Thanks, @Papa!

Capture.PNG

[Papa]

You'll just need to remove the tether and the cap will fit perfectly.

[first time builder]

I cant see for sure is the vent hose being pinched by a zip tie ?

[AdamIsAdam]

I don't think so but I'll check.

[CraigS]

I always run w/ < 1/2 tank gas.

[AdamIsAdam]

Yea, looks like you're right. But the auto-x event was located about 12 miles from the nearest gas station and I wasn't sure how much gas my Holley Double Pumper would use in a day of auto-x. Lots of idling around too. My GT350 got 6 MPG on the road coarse track and I went through an entire tank and had to pay track prices for gas! But that's a lot more driving than auto-x is.

[Jeff Kleiner]

I had that happen once but it was because I'd left the screw on cap laying on the pump at the gas station (DOH!) It sure did get the course workers excited Suffice to say the LeMans caps don't seal!

Jeff

[wareaglescott]

Any possibility it is coming out the side of the tank where the filler tube inserts and is still ending up on that side of the car? Are you sure it is coming out the at the cap? I assume not because you said it spilled down the fender.

[AdamIsAdam]

It was coming out of the cap for sure. It was wet when I looked at it. And look at the pic I posted, the gas was flowing down the fender. No way that came from the tank itself. I expect a new gas cap will be the fix.

[Papa]

The issue I had with the original cap is that it wouldn't properly close, or would "unlock" on its own. I discovered this when I couldn't open the cap one day. It wouldn't turn. After some time, I realized it was already open and I just had to lift it out. Ask Jeff Kleiner, as it happened to him while he had the car as well. I replaced the cap with the Ford part and have not had any issues since. I know the cap seals well, as I have to slowly vent it when I open it after driving.

[AdamIsAdam]

Interesting. I have NEVER heard air escape when I opened the cap to refuel. And while at the auto-x, it didn't leak out initially, it started on run #2. I turned it closed a few more clicks, but didn't open it so I don't know if it was already opened. And after I clicked it closed I THINK it didn't leak as much for at least a few runs. I just assumed it varied based on my turning (ie, maybe I was faster/slower on a given run) but maybe when I clicked it shut, it stayed shut for a few and then came open again. Hopefully the new one cures all.

[phileas_fogg]

This has been a problem since at least 2015: https://www.ffcars.com/threads/mkiv-.../#post-4965153


John

[AdamIsAdam]

Wow! Yup, mine is the wrong one based on pics.

I can't imagine not using that inner cap and just relying on the LeMans cap. I have both and gas flew out!

[Railroad]

The issue I had with the original cap is that it wouldn't properly close, or would "unlock" on its own. I discovered this when I couldn't open the cap one day. It wouldn't turn. After some time, I realized it was already open and I just had to lift it out. Ask Jeff Kleiner, as it happened to him while he had the car as well. I replaced the cap with the Ford part and have not had any issues since. I know the cap seals well, as I have to slowly vent it when I open it after driving.

The slowly vent on opening, does not sound right. Your tank vent should prevent pressure or vacuum. IMO

[AdamIsAdam]

Amazon arrived. I went to the garage, opened the LeMans lid, grasped the old gas cap and IT PULLED STRAIGHT UP AND OUT! I reinstalled and removed several times only to realize it was just resting on top of the filler neck!!!!

And now? I got better...
https://youtu.be/J6pZuAJjBa4

20201111_114752_HDR.jpg