I have a 66 Dart. Factory tank but it has been modified for a sump kit welded in. The fuel lines have been increased in size to 1/2” going from the pump just below the tank up to the fuel regulator mounted on the passenger inner fender near the alternator. From there the fuel one runs to carb inlet. The return line goes from the regulator back to the tank and it is also 1/2” line.
So twice now I have filled up the fuel tank, drove 5 miles or less and shut car off inside garage. Outside temps both days were around 80*. After the car sits for approximately 3-5 minutes gas starts pushing out behind the gas cap. Neither time was there pressure built up behind the cap when I removed it.
There is a vent in the system in the fuel neck. Any ideas why this is happening? Do I need to install another vent on the top of tank? What’s your thoughts?
Thanks Rod
