Fuel coming out vent

[ErikSOCAL]

My tank is getting pressurized and pushing fuel out the vent. Full tank. The steady dribble of fuel out the vent stopped when I released the gas cap and the pressure with it.

Don't recall having this problem before... although I've only had the opportunity to top off the tank 2 other times at most over a 2 year period. The car has been sitting in storage a while and I finally ran enough of the old fuel out to go fill up with fresh fuel.

Specs
-Running a sbc w/edelbrock pro flo efi (old style).
-Ricks tank with an intank walbro 255
(I realize this is a lot of pump. the original plan was to go right to LSx motor but that didn't happen)
-using the Stant fuel cap that came with the tank.
-The edelbrock efi uses around 28 psi fuel pressure.
3/8 inch main and return line.

Have rubber fuel hose attached to the tank vent fitting, its run up and is attached over the differential with an extra 3 or so inches hanging off the end. On the end I have sintered bronze fitting seen here at the bottom: http://john.my67.net/engine3.htm

What's going on here and how do I fix it? thanks!

[formula]

Have you tried putting a giant cap on it? Or maybe a top kill with some heavy mud?


Sorry, I had to.

[ErikSOCAL]

Lol, I'm going to pollute the environment first then go file a claim at the local bp claims center. Actually the car is stored here on the FL panhandle, I better go snap a few pics of the car by the pristine beaches pre spill.

[mrn2obelvedere]

I have an idea of what might be happening.

When your tank is full, the fuel might go right up to the fuel return vent inlet. It is possible in this case that pressure can build up in the tank and push fuel out of the vent tube



That's my theory.

[ErikSOCAL]

Dang Sean, diagram with the answer! Couldn't ask for more! I think your right. With the tank pressed up full the vent outlet is in contact with the gas allowing contact and a siphoning effect. However, I thought there was a check valve in there in case if rollover? Maybe it's just enough pressure to allow fluid to go by. Drove the car a bit and with the fuel level down some, hasn't done it.

[mrn2obelvedere]

It was easier to draw the diagram than it was to try to describe what I was thinking...

Hope it can be helpful!

[130fe]

Erik, here is another option for you. Check out what DSE did to Colt Zantop's car- http://www.detroitspeed.com/projectp.../colt_main.htm He (Colt) told me had didn't have any issues with that particular vent line. I had a similiar issue to you with my old rock valley tank. I just capped it and never had any problems. On my new Ricks tank, I am running a ridetech filler neck that has a vent fitting on it.

BTW, Great to meet you today and thanks for bringing your nice car out to our Cars and Coffee cruise. As you saw our turnout with pretty low but I expected it with the holiday weekend.

[zcrz]

I was having the same problem with my Rick's tank, they had me plug it (vent line) and they sent me a different vented cap. Seemed better, but I think It might still do it after I fill it up, I
havent done that this year yet.

[ErikSOCAL]

Chris, great meeting you and awesome ride. Enjoy Chile too!Thanks for the link, I've looked it over and the only difference I can think why he isn't experiencing it is the location. My set up has basically enough bends to equal 180 degree loop and some elevation too, I don't recall where the vent fitting is but it must be near the pump which is center.

Doesn't sound like I lose anything just plugging the vent. Not to interested in having fuel spewing between to hot exhaust pipes.
Want to make sure I got the functions right:
-Is the cap one way (in)?
-the vent 2 way, function is to allow air to escape when filling up.

zcrz, fill up and hit the road, I need real world results!!

[parsonsj]

If you want the best fuel vent setup around, drop me or Mike Norris a line.

II Much, FUel, Bad Penny, The OneLapCamaro, and MotiV8r all run one. They aren't cheap, but it will solve your fuel vent problem.

jp

[ErikSOCAL]

John,
I found the link with your device. It looks great, one question I have is where are they being mounted? want to avoid bringing fuel inside the car. that thing sure is a work of art!

just a little background for everyone, I'm probably overly hyper sensitive around fuel. But after being blown up and having a fireball come through a boat due to a leaking fitting on a carb I dont feel bad being paranoid!

Do I lose anything just plugging the vent? A $2 plug fitting is more attractive if nothing is lost.

[mrn2obelvedere]

John,
I found the link with your device. It looks great, one question I have is where are they being mounted? want to avoid bringing fuel inside the car. that thing sure is a work of art!

just a little background for everyone, I'm probably overly hyper sensitive around fuel. But after being blown up and having a fireball come through a boat due to a leaking fitting on a carb I dont feel bad being paranoid!

Do I lose anything just plugging the vent? A $2 plug fitting is more attractive if nothing is lost.

I hear you man. I had 3rd degree burns on my whole lower leg involving gasoline. Skin grafts and all. I am terrified of fuel and about as paranoid as you can get.

[Vegas69]

I run a set up similar to what John is recommending. You must mount the canister in the trunk and vent it back out of the trunk. There is no place to get it high enough otherwise. I used a bulkhead and grommet.

[ErikSOCAL]

Todd,
Any chance you can post or email me a pic? Do you need to have some sort of 'firewall' to meet safety rules for racing events?

[parsonsj]

What Todd said: mount the vent/baffle in the trunk, then run the output from the vent/baffle to a breather outside the car.

No fuel leaks, no spillage during high-g maneuvers, no gas smell.

There could be an issue with certain sanctioning bodies about having the vent/baffle inside the car, no doubt. We hid Larry's up under the lip of the quarter panel.

Note that all of the above cars have run freely at every venue they've entered. Not one was kicked off the track due to tech issues with the vent/baffle.

jp

[ErikLS2]

Anyone here tried using an OEM charcoal cannister? I haven't done it either but after reading about all these venting issues I am considering it. Should work though with a GM computer provided the EVAP system tests can be turned off without affecting purge operation.