Sometimes after a cruise my car spews gas out of the gas tank's ventilation tube. It doesn't happen every time but when it does it usually happens 5 to 10 minutes after I turn off the car. If I had to guess I'd say it spits out about 1/4 cup of gas just behind the passenger side rear tire. Any theories as to why this would be happening? Obviously it's a dangerous situation that I want to fix ASAP.
A little about my car. I'm running a 496 BBC (480hp/580tq) with an electric fuel pump and a 5/16" fuel line. It doesn't have a return line. The tank itself is pretty beat up (surface rust and some big dents) and is most likely original to the car.
I've been thinking about replacing the tank, straps, sending unit and changing to a 3/8" fuel line and a mechanical fuel pump. Other posts indicate Spectra makes a good affordable tank. Any suggestions on where to buy the fuel line and fuel pump?
All 65-66 B body cars had a vent tube that ran up into the trunk and back out the bottom ,the cap is non vented to keep fuel from splashing out the back of the car.
There is a short piece of fuel hose where the vent tube comes out of the tank and attachés to the metal line that runs up through the trunk and back. That hose and the fuel line hose should be replaced every couple years as the alcohol in our fuel dries them out very fast. That also goes for all the fuel hose near the motor also. Check your vent hose at the tank.
If you use an electric fuel pump you should use a return line as unlike a mechanical pump that changes volume output to match engine RPM an electric pump moves the same volume of fuel all the time it is on. So at idle you are flooded in fuel and at wide open throttle you are probably starved for fuel.