Hi,

Whenever i go to gas up, when i remove the gas cap theres no pressure there.

I have a brand new gas tank and filler neck (both spectra), the OEM cap didnt fit, i bought a new one that seems to fit but i dont think its fitting right. It will screw on, but when i take the cap off the gasket that seals on the brim of the filler neck is wet, like fuel is splashing on it or something. It smells slightly of gas back there, sometimes more than others for some reason (probably more noticeable when driven hard.) i know you cant use vented caps, the new one is NON vented. I can still burn rubber pretty easily, but it doesnt feel like its at 100%, something still seems off to me. Any suggestions?

 

Is there supposed to be pressure in the tank? One of the lines coming out of the sending unit goes to a breather behind the driver's rear wheel so I assumed there wasn't supposed to be any pressure in it.

Also, didn't your new tank come with a gas cap? I know its been about 2 or 3 years since I bought mine but it was a spectra tank with the filler neck attached and it had a new gas cap in the box..

 

I also get pressure when I go to take my gas cap off. Would like to know if this is normal or causes any issues as well.

 

Well i didnt get a cap with it, just the filler neck. I thought that was dumb, but i though tthe neck would work with the OEM cap. Can you get me a part # for that cap? It'd be very much appreciated!

@hydrolic144: IDK, i thought there was supposed to be pressure but it sounds like theres a possiblity there isnt.

 

I am almost positive there is not supposed to be pressure otherwise they would not put an open tube on the sending unit that is just to keep the pressure at normal atmospheric pressure.

 

I didnt know there was an open tube on the sending unit.

But if this was the case, wouldnt they just use a vented cap?

BTW, i put a vented cap on the car and it made the car lose alot of power, hardly could even break the wheels free from a standstill. So this makes me think theres supposed to be pressure in the tank.

Besides, all other cars iv ever put gas in (alot) have always had pressure in the tank. Im pretty sure the iroc is the first ive ever seen that doesnt

 

Ive had three vehicles all different makes but Ive never had one that keeps pressure. I recently changed the sending unit and fuel pump in my 92 Z28 thats how I know that there is a vent tube to equalize pressure. I am pretty sure that the cap i use is the origional and it is vented but i feel no loss of power.

 

The stock cap is supposed to be non-vented (at least it is for '88) but im fairly sure all yrs are same cap. Im pretty sure even 4th gens use non vented. Have u ever put a non-vented on it to see if theres a difference? i had a big loss of power with vented, and theres been others that have said the same (theres another thread or two where people said the same on here)

 

I Have never had a problem with power at all, I'm not saying i know for sure I just know the sending unit definitely has an open tube to equalize the pressure, so I am not sure how you could actually build up pressure

 

I believe it may be something along the lines of if maybe the fuel is low it'll release some pressure. How much gas you got in your tank when it does that Black88Z?

Another thing also, if it's not supposed to release pressure, may wanna look at replacing that vent that comes off the tank.

 

Its never done it, and ive checked it at all kinds of different levels thinking that was the case. ive even filled it, ran it almost empty and it still had nothing. Even filled it and drive it hard, then checked. Still nothing.

 

OH!

I totally read your title wrong. Been a crazy day for me lol.

I think that may be normal. To me it would seem your vent and charcoal canister are both working as they should. Just sounds like the logic, but I'm no expert here.

 

You aren't supposed to have pressure built up in 3rd or 4th gens. They come with non vented caps.