Fuel leaking at cap LOTS OF PRESSURE!!!

[chuzie]

I actually rode the trail yesterday with a real gascap installed!

Here is the problem I ran into.

I let the rig sit at idle for about 20 minutes and not at some extreme angle or anything. When I came back fuel was dripping from the fuel cap. When I cracked the cap there was a LOT of fuel that wanted to come out so I tightened it back up. It was under quite a bit of pressure.

I do run an EFI system so I thought maybe the return line was feeding more than the engine was consuming so I drove for about 5 minutes to try and neutralize the tank overpressure situation by consuming more fuel than would be returned to the tank but it did not help.

I thought maybe it was because I had just filled the tank up that morning and there was very little air for the cap to release so it released fuel instead. That makes me wonder if the pressure is a normal condition and I just never notice it because it is not fuel being vented.

I ended up parking the truck at an angle to allow the air to move to the filler side of the tank and was able to remove the cap to release the pressure without loss of fuel.



Can someone confirm this for me?

[Timstrk]

Without EFI you shouldn't have a return line to the tank. It should be a draw only system. There were vent lines running to the charcoal canister behind the passenger front wheel. A round can about 8" tall and another behind the driver's seat in the side of the truck just behind the striker post. Those should vent any pressure that would build up in the tank. Are your vent lines crushed or capped off for some reason? PO? Filler should have 2 small lines coming out of it, on the tank itself. One to the carb and one to vent. I dumped fuel because of the bad cap seal but hopefully no more. New caps like yourself.

Tim

[broncomania]

you need a vented cap.

[Mill Knob]

I had the same problem with my 69. I am not running a EFI set up. I found that there was a belly in my filler neck hose. So gas was just seating there. Make sure that the filler neck hose is straight up and down.

[chuzie]

I am running EFI.

[Mill Knob]

I am running EFI.

I under stood that. Was just giving you my 2 cents. Sorry..

[broncomania]

I under stood that. Was just giving you my 2 cents. Sorry..

he was letting tim know he has efi.:beer:

[Mill Knob]

he was letting tim know he has efi.:beer:

10-4

[bucketobolts]

Sounds like you need a charcoal canister of some sort. Tim referred to factory one. I also think some of the later models had one in the drivers quarter panel in front of the wheel house.

You may could get one from a late model FI car or truck and modify it to work. Either way your tank was venting with the bad fuel cap and now it is air tight with the new one. You could always use JP's WalMart bag and rock:hysterical:

[chuzie]

Sorry Mill, that was for Tim.

Bucket, the bag and rocks were mine; for the record.
I will look into the canister. Thanks.