What causes to much pressure build up in gas tank?

[1SYCLONE1]

Hi, my syclone seems to have a lot of pressure build up in the gas tank every time I go to remove the gas cap. Will this cause any issues or should I not worry about it? It always has a lot of pressure no matter if the tank is near empty or full. Thanks.

 

[Robert Lone]

Re: What causes to much pressure build up in gas tank?

Mine does it too.

I ignore it....

 

[fronzoos]

Re: What causes to much pressure build up in gas tank?

Mine does it too.

I ignore it....

x2

 

[Norm]

Re: What causes to much pressure build up in gas tank?

How about using a vented cap?

 

[BoostedSUV]

Re: What causes to much pressure build up in gas tank?

There shouldn't be any pressure... I had that happen in my el camino when the cap wasn't venting properly. Damn near sucked the gas tank closed!

 

[1SYCLONE1]

Re: What causes to much pressure build up in gas tank?

will having to much pressure in the tank cause any problems with how the truck performs ?

 

[1SYCLONE1]

Re: What causes to much pressure build up in gas tank?

There shouldn't be any pressure... I had that happen in my el camino when the cap wasn't venting properly. Damn near sucked the gas tank closed!

how can I check to see if I have a vented cap or not? Where can I pick a vented cap up at? Will it hurt anything if I run the truck without a gas cap? Thanks.

 

[Don W.]

Re: What causes to much pressure build up in gas tank?

Without checking doesn't it vent, vac & pressure, through the canister? If so then something is plugged. I get -0- pressure on the Sy.

 

[BoostedSUV]

Re: What causes to much pressure build up in gas tank?

Is it pressure or suction? If the tank is not vented properly you can create problems. The fuel pump will not be able to move fuel... Its like sucking on one of the juice sip boxes once it runs out or air/juice. It just sucks to a certain point and once there is not more vented air it can't suck anymore. Or you're retun line is pumping in pressure and expanding the tank... Either way is sounds like a gas tank vent issue. Could be something as simple as just the gas cap...

 

[gkrcr882]

Re: What causes to much pressure build up in gas tank?

A vented cap allows air into the tank to replace the fuel being removed, to prevent a vacuum and the tank from collapsing. Excessive pressure in the fuel tank is related to the evap system. A small hiss is normal, while trying to keep the cap from blowing your hand off isnt.

 

[1SYCLONE1]

Re: What causes to much pressure build up in gas tank?

Well can I run the truck without a gas cap or will that also cause problems? Thanks again to everyone that has chimed in:tup:.

 

[gmcturbo]

Re: What causes to much pressure build up in gas tank?

just go buy a new cap at autozone theyre cheap. your gas wil evaporate and get contaminates in without a cap.

 

[s_blazin]

Re: What causes to much pressure build up in gas tank?

on a couple gas stops headed to and from nats we found the ty having pressure in some of the hotter states, seems the gas was just expanding.
:2cents: :dunno:

 

[ty1025]

Re: What causes to much pressure build up in gas tank?

yeah the evap sounds like its not working, should be putting the excess pressure thru the charcoal canister i believe. i know that it is a semi sealed system though so a lil is normal. clogged lines?? clogged canister just my:2cents: and i agree running w/o a cap is bad for the gas but also dangerous as the fumes ignite.

 

[TYRODD]

Re: What causes to much pressure build up in gas tank?

I removed my charcoal canister, and capped off the vent line...no problems here:dunno: