pressure inside gas tank, advice needed

[dymz999]

From my research and what everyone tells me the gas tank in any vehicle should be under constant vacuum. This week after my car had some issues, well i started to notice that the gas tank was under pressure, so much so that it was spewing out fuel where the fuel pump bolts into the tank. i had a new o-ring gasket and even put rtv silicon gasket on it. It somehow still sends gas out which is by no means normal. I could see it leaking out after i fill it up but right now its 1/4 full.

Vacuum dropped by 4 psi at idle which makes me belief there is something causing it to happen.

Anyone have any ideas???

Edit: this is on a sr20det powered 240sx.

[benyl]

when it is hot outside, gas expands... A LOT.

But if this happend today (relatively cool) then I don't know what to say.

[bspot]

Yeah, its totally normal to end up with a pressurized tank. Most owners manuals even warn you to be careful when opening the cap.

[rc2002]

The fuel pressure might not be correct, have you tried hooking up a gauge to it? You don't have an adjustable fuel pressure regulator do you?

Also, you may not have a good seal between the tank and the fuel pump if it's spewing there. Maybe there's no good connection due to corrosion? Or the O-ring is the wrong size?

[schurchill39]

I have gone to fill my car up on almost empty and still had a little bit still spew out when i first open the cap. So unless its a pretty rediculous amount i wouldnt worry about it

[Audio_Rookie]

you got a vapor canister hooked up?

Had similar problem once....if theres a line going to you vapor canister from gas tank unplug it take it for a spin, see what happens.

And it usually does expand a little, but what your explaining seems very excessive.