fuel problem

[Joe Dirt]

Ok guys last night i filled my car up I noticed when I removed the cap it seemed to have an excessive amount of pressure (hiss) so i filled the car up left the cap about a half turn loose and headed home well today i go out and i smell gas as I aproach the car and gas is running out the filler neck like a river (cause of the cap loose)

now to my questions

How is the tank vented? purge selonoid?vent and carbon can?

Is the oem cap vented? its got a stant cap on it now not sure if it is correct

[wybnrml]

Festivas do that, mine does it, my past Festivas have done it, you might try going to the parts store and buying a vented cap.

[Biff]

I dont know how the tank is vented, but pretty sure there are several fuel lines from the tank to the engine bay.
Mine vents a fair amount of pressure when empty and the cap is removed for fill.
I figure that to be a good thing to have a positive pressure in the tank helping fuel into the tank pump and up to the engine.
There is probably a schematic of the fuel lines some where on here? That would show you...

[resuwrecked]

you dont want a vented cap, thats what the vent line and canister is for. its under the brake booster. it may be clogged. but then again, i removed my canister and still have the hiss. I wouldnt worry about it, all cars hiss, use your stock cap and tighten it normally.

you have a fuel supply, fuel return, and vent line going to the engine bay from the tank. vent line goes into canister, out of canister, to purge valve, then to intake.

[Pu241]

you dont want a vented cap, thats what the vent line and canister is for.

^^^ Agreed, use the OEM cap.

Mine hisses sometimes, and I run a lot of gas.
Understand the fuel pump is cooled via the fuel.
If your low on fuel, there is less fuel to dump heat into, so it's temp my get higher.
With 10% ETOH, you could well volatilize the ethanol as well as the low boilers in the fuel creating the gas pressure you hear when you open the cap.
It seems to be worse on hot days, toward then end of a tank of fuel.
But never worried about it.
Filled it with fuel and tightened the cap 3 clicks and on my way.
When I say fill, I mean fill, I've put 10.3 gal in the 9.9 gal tank!