I have a problem with a 1972 cutlass convertible. Fuel is pushing out of vent line on new gas tank with Fuel injection and internal fuel pump. What is the large metal box behind the rear seat that the fuel vent lines disappear into?

 

I think it is a vapor condenser. How do I hook it up to a tank that has only 1 vent? Does anyone have a drawing of whats inside?

 

What are you calling "one vent"? The stock tank would have had vent tubes in the upper front corners that attached to the cannister behind the seat. This is shown in your Chassis Service Manual, by the way. The sending unit could have had one or two lines, depending on whether the car had fuel return or not. Where exactly is fuel coming out of? The fuel coming back from the EFI is at 40 psi or more, so it must go into a sender with fuel return, not into a vent line.

 

http://www.tanksinc.com/index.cfm/pa...rod/prd387.htm

Fuel out, fuel return, and 1 vent

 

Again, where is fuel coming out of your tank? That vent fitting on the sender? Do you have it hooked up to anything else? If not, of course fuel will leak out of it. The vent fitting needs to go to a line that runs in an inverted "U" shape, with the peak considerably higher than the top of the tank. You can run it to the separator under the back seat (cap the other line) then run the vent from there to somewhere safe, like away from the exhaust.

 

fuel is coming out of the vent. I assume that the separator has a output / vent that pulls from the top and 3 inputs that go into the bottom. There are 4 hoses in the bottom. I am just confirming that I understand what is going on inside it.