Gas tank vent?

[DMC3165]

Where do our gas tanks vent from? I've been having a persistent problem with my fuel pump boot popping off since day 1. I always thought it was do to an improper installation but it has been done at least a half dozen times and not all by me.

The reason I ask tis is today I was using the car most of the day and the tank was full right from the start. By the end of the afternoon I started to smell gas from the tank area. So I went home to see if the boot had popped off again but to my surprise it was tight. However the top of the tank was wet with gas.

My only theory at this point is the tank is not venting properly and the hot gas is pressurizing in the tank? If its as simple as replacing the gas cap I'll try that first. But would like some forum feedback first.

Thanks

[Ron]

It is a closed system...

I'd dry it off and see if you can catch it leaking. I'm guess you've tried before...like watching for water to boil. Baby powders can help you find the trail.

[stevedmc]

Check your connections from the tank to the filler cap. I had a cracked hose that was causing fumes/fuel to vent and leak. I brought the cracked hose to Autozone, showed it to them, and they replaced it for a few dollars.

[Elvis]

which cover for the fuel pump do you have ?
the original one or the new one ?

I got it from Ed Uding, I guess it's a good and improved product from DMCH.

AND the fuel pump has to sit deep enough so that it doesn't push the cover up.
106684 FUEL PUMP COVER SEAL
http://www.delorean.eu/catalog/index.php?cPath=19_25_48

click on #1 and check out how the new cover looks like.

It solved the problem on my car last year.

[stevedmc]

which cover for the fuel pump do you have ?
the original one or the new one ?

I get my fuel pump covers at the dollar store. You can get about 20 bags, i mean covers, for just two or three dollars.

[aludden]

I get my fuel pump covers at the dollar store. You can get about 20 bags, i mean covers, for just two or three dollars.

Are you putting pooper scooper bags?

[dustybarn]

The fuel tank vent is connected to the carbon canister. If the hose leading to the canister is blocked, the canister itself is plugged, or the canister vent outlet is plugged (by, perhaps, a wasp nest or something) the tank vent system won't work properly and vapor pressure may build up in the tank.

[Rich]

++ on dustybarn's system description. With the fuel pump boot in place along with tight connections at the filler neck you should not see any raw gas - ever.

The boot's not designed for pressure or vacuum.

Is the vapor vent clear? Check it upstream and downstream at the connection in the engine bay. The metal vent tube pops up near the left frame member near the firewall where it connects to a black hose connected in turn to the charcoal canister inside the left pontoon. Break in here. With the fuel cap off you should have open flow through the tube toward the tank. Then check for open flow back through the hose to the canister regardless of the fuel cap.

Photo here shows the vapor hose leading forward from the canister toward the vapor vent tube that runs forward to the rollover valve near the top of the filler neck.

IMG_4718.jpg

[stevedmc]

Are you putting pooper scooper bags?

Gallon size zip lock bags.

[Ron]

You guys have all of this backwards...

It is a closed system -- If the vent hose is plugged, it will not cause vapor leaks -- it can cause the tank to collapse!
If you have a port on your canister that has nothing on it thinking it is a vent, buy a blanking cap from DMCH(#12)

Read D:06:01 thru 03 in the Workshop Manual (Page 40 in this pdf file).

(Not Steve, he has a carb...but he knows where to stick it ;-)