gas tank is now pressurized

[BangkokDean]

I recently installed a charcoal canister that was missing from my fuel tank vent.
The vacuum line off of it is connected the the bottom of the carb port that was original connected to the vacuum advance bottom right. Yesterday I noticed the the gas tank is now pressurized so when i removed the gas cap there was a whooshing sound like releasing the pressure in it. My question is will the build up of pressure hurt anything like the fuel return from the carb? If so where should I take the vacuum from to pull more from the canister?

 

[010752]

I just leave all the ports open at the cannister and have no gas odors and no pressure.

 

[mrvette]

I recently installed a charcoal canister that was missing from my fuel tank vent.
The vacuum line off of it is connected the the bottom of the carb port that was original connected to the vacuum advance bottom right. Yesterday I noticed the the gas tank is now pressurized so when i removed the gas cap there was a whooshing sound like releasing the pressure in it. My question is will the build up of pressure hurt anything like the fuel return from the carb? If so where should I take the vacuum from to pull more from the canister?

The ONLY time I ever noted pressure in the tank with the cap release, was when the tank was nearly full and in my '72 there is a little float valve with a ball check in it, to keep the gasoline in a full tank from going into the line leading to the canister, it's a black plastic cube with two lines going to it, one to the tank the other forward to the canister....when I filled the tank the ball would naturally float to the top and stay, as the gas was warmed by the engine and Florida weather, the pressure in the tank would build, and sometimes even stay overnight, believe it or not,

now as I have also had a vacuum in it...one thing noticed is the valve on my canister was not working well, the small control line to the intake mani vac port was not functioning, I think it must have had a problem allowing engine vac to get to the fuel tank, so what I did is pull the thing off, and just allow the large line to the engine to the air induction BEFORE the throttle blades, mild vacuum point there,

what cured all this pressure crap going positive when I filled the tank, was a locking VENTED GAS CAP....I was nervous about fumes in the garage overnight, but never an issue....

I have also seen other cars have issue with gas tank pressures or vacuum also, just drill a tiney hole in the gas cap is about all we can do...

:drink:

 

[BangkokDean]

I just leave all the ports open at the canister and have no gas odors and no pressure.

I can give that a try.

Mrvette. thanks for your ideas, the pressure was with a 1/4 full tank........I will try taking the hose off the carb first to see if that releases the pressure.

 

[mrvette]

I just leave all the ports open at the canister and have no gas odors and no pressure.

I can give that a try.

Mrvette. thanks for your ideas, the pressure was with a 1/4 full tank........I will try taking the hose off the carb first to see if that releases the pressure.

Hose to carb can only cause a vacuum, not pressure...I like Noonie's idea better, really thinking back on it all....

:bump::devil::withstupid: