gas tank relocation problem

[vasquezmrysvll]

i just finished my relocation using a tank from 76 chevy van with a stake pocket filler. my problem is the tank builds pressure (alot) with the cap on (marine filler just like johns).im using one vent to let air out when filling, and a one way from a iroc to let air in while the fuel pump pulls fuel.

[Sammy]

From your explanation it appears the tank still isn't venting. Might check to insure the check valve isn't installed backwards. (Could be marked wrong or defective) The vent check valve I used was found on a 75 chevy truck frame. Real simple plastic ball type valve. Which is higher than the tank mounted under the bed. Then the filler neck is vented to the tank about two inches below the cap. Just shooting ideas your way.

[Mowdigger]

Have you checked to make sure your vents are not plugged? Or maybe the vent hose got kinked, just a thought.

[vasquezmrysvll]

yes the fill vent is 2" below the cap in the fill neck. and the one way is operational with no restrictions. but my system has no way of venting out of the system with the sealed gas cap installed? could i remove the iroc 1 way and just run a vent line somewhere?

[Sammy]

I did till I found a check valve. Problem is that when I filled the tank to full it would overfill thru that line over board before the auto shut off would kick the pump off. What I did was left the ign on watched the gage thru the back window. Also you may run the risk of getting dirt thru that vent. i dunno how much if you locate it safely?

[vasquezmrysvll]

could i cap off the open vent line with a cheap fram
plastic fuel filter so no debris will enter my system? and will i run into any problems with running an "open" vent?

[VA72C10]

interested in this because I will be running a similar setup...

[Sammy]

I haven't filled my tank to full since installing the new check valve but common sense tells me that it will discharge the excess fuel prior to shutting off the pump unless that vent is higher than the spot of your refueling point. Which is going to be an issue in your case being so high. And anything such as a filter would help preventing foreign unwanted stuff couldn't hurt. Some have used a check valve from ebay designed for motorcycle fuel systems as they are $10 or less shipped. Your first issue is too cure the over pressure issue then experment with what works best. Good luck.

[crakarjax]

On 68 chevelles there is a vent tube in the back of the gas tank. It is probably for releasing pressure since when I plugged it the tank built a lot of pressure. Anyway, a lot of people have issues with fuel spewing from that vent tube, including me. Sounds like the solution to your problem would also be the solution to that problem, which would make a lot of people happy in the temchevelle forums! Subscribed.