I need some help with my car guys. Everytime I open the gas tank cap, whether it has a full tank, half tank, empty tank, a lot of air blows out of the gas tank. Once the air stops blowing out, I put the cap on, and 10 seconds after, open it again, and the same air blow comes out. Also I am getting a "fuel" smell really bad, but no fuel is leaking anywhere. Is this a problem with the evap canister, or valve? Thanks!

 

Anyone???

 

Are ya sure it's blowing out and not sucking in? I presume ya upgraded your fuel system a while back and it may not have enough vent area.

 

yes it is blowing out. My fuel system is stock, besides 42lb injectors and a fuel pressure regulator. Besides that everything else is stock...

 

To have pressure or vacuum in the tank means it don't have enough vent. There is a white plastic check setting in a bracket where the metal brake line comes to join the flex line going to the rear end.Left side right on the inside of the front of the L rear tire. Check it and see if it is working properly.
There might be a chance that the charcole canister under the left front fender is kapoot. Disconnect it and plug the lines, if the check is working.

 

i think i heard its beacuse we have a posative pressure tank or seomthing...dont worry mine does the same thing

 

The charcoal canister is just behind the gas filler neck, in the drivers side quarter panel.

 

LOL... You guys are getting too technical for what could be a simple problem. Is your gas cap vented or not vented? A typical thing to happen with a non-vented gas cap is more pressure will build up in the tank. If you have a vented gas cap and you still are having problems then move on to the other "ideas". My 1991 Geo Storm (Winter Beater... HELL YEAH ) didn't have a gas cap when I bought it for $100... go figure... and I put a non-vented and it did the same thing my Camaro does. I work at a parts store so for ****s and giggles I bought a pre-vent and boom, problem fixed.

Just my 1/64 of a cent...

 

i dont have a vented cap, but if you put one on, wont you get a SES light?

 

I had the same symptoms and it was the pressure relief valve mentioned earlier. Initially I solved the problem by putting a vented locking cap but then I kept failing inspection because they check those things in Jersey.

It is a big problem if you have a white Z like I do because the paint gets stained when it blows out. The valve was cheap and easy to replace.

 

Nope... at least I haven't. As far as pressure checking I pass the Indiana inspection... they put 30 PSI on those suckers and I still passed w/o problems. My check engine light don't come on either. It will come on if you leave your gas cap at a gas station though...

 

What is the name of that valve? Fuel Tank Vent?

 

Check this picture on Shoebox's site...

http://shbox.com/1/fuel_pump_wiring.jpg

He calls it Fuel tank vent.