Gas leak, kind of weird

[D_Eclipse9916]

Alright so ive been battling this problem all the time for some reason. I have a 255 walbro in my tank. After filling up I would drive and then stop, turn the car off and come back, and all the sudden ive lost literally an 1/8 of a tank of gas, it kept doing this so one day I looked under the vehicle and it is losing gas from the top of the tank....I think. So I make sure to lossen up the plastic fitting and tighten it down again. That "seems to fix" the problem. Now 2 months later, I change out my fuel filter, and im having the same problem, and no its not from the fuel fitler, ITS AGAIN leaking from the tank. I check the fitting and its tight, and seeming to seal, anybody got any suggestions? I am about to freaking throw some rtv sealant on all the threads and do that.

Could pressure be building up, it really only happens over half tank of gas. I have my charcoal canister and all emissions equipment removed. The hard line from the tank that goes to the charcoal canister is just dumping to atmosphere. Could that be it? How bout the gas cap? Could it not be working and be building too much pressure and pushing the fuel out the top?

 

[15poundsoffun]

any puddles anywhere of gas, if not then check to see if the gas gauge is working right take the sending unti back out and it is the big square thing see if it is sticking anywhere it the movment up and down up meaning fulll and down meaning almost out of gas you could turn the car on with the sending unit out just make sure the fuel pump isnt going to come on.... and repeat the up and down see if the gas gauge it reading right

i have had this problem before and the gas always seemed to be going but when it got near a 1/2 of tank it wouldnt go as fast as it did so hope it helps

 

[FORMONTOYA]

Did you plug the tank vapor line when you removed the emission items. If so, then I imagine that's your problem. The tank builds up pressure and has to vent somewhere and the closer to the "vent" the gas is (like over a 1/2 tank if it's "venting" from the FP assembly), the more you will likely lose.


I had a different issue related to the vapor line. I had a "wild hair" and decided it was time to do a massive under-body/wheel well cleaning. During this I somehow managed to kink this line. After that I noticed that my fuel pressure with the hose on was at 39PSI when it should have been at ~34PSI. After a discussion I was directed to the vapor line. I did a little searching around and found I had kinked the line during my cleanup. Un-kinked the line and the fuel pressure came down to the normal ~34PSI I should have. The kinked line was allowing pressure to build and thus effected my fuel pressure at the rail.


I kind of "high-jacked" the thread at post #24, #47 is where the issue was solved (thanks again John!).
http://dsmtuners.com/forums/showthread.php?t=207720

 

[D_Eclipse9916]

Yeah I have it uncapped, beleiving that it needs to loes pressure....but its not leaking from there, its literally leaking from somewhere on top of my gas tank as the gas puddles form right under the tank and you can see where gas came out, but I Cant see on top.

 

[FORMONTOYA]

How about the rubber gasket for the fuel pump assembly cap? That can sometimes be a PITA to get back on correctly with everything that's going on during installation.

 

[15poundsoffun]

yep i thought it might have been a line you might not see it well but most likely what it sounds like is a line has a hole in it if it was pressure most likly it would come out the gas cap or the rubber around the sending unit to tank can you drop the tank alittle to see if you can see up there anyway but if theres a puddle then your lossing it

 

[D_Eclipse9916]

hahaha aw ####, what rubber gasket???

I think I may have found my problem, damnit! I feel really stupid, something so simple.


Edit: Why cant I give you guys reputation points?

 

[FORMONTOYA]

You can here:
http://dsmtuners.com/forums/forumdisplay.php?f=101
It's just a little more cumbersome due to mis-use.

Don't feel bad, it's usually the simple stuff that gives the biggest problems.

 

[15poundsoffun]

glad to help if that fixed it or not so let us know so others may have a fightting chance