Can I plumb the vapor separator line (from Fuel filter) to the fuel tank vent line that runs along side the fuel supply line? (This is on a 74 Ramcharger 440 truck).

I'm having some vapor lock issues sitting traffic idling (such as waiting in the ferry lines to get to the island) in this 100* Texas heat. Currently the vent line is connected to the charcoal canister that is still in the passenger side wheel well, but isn't plumbed into anything else.

My concern is that I may pressurize the tank or bring on other problems that I don't currently have.

The canister can should be vented on the bottom with foam acting as a filter

I assume the truck systems are similar to the car systems....

The gas tank is vented through the charcoal canister. If you use that line for a return, the tank won't have a vent UNLESS you use a vented gas cap. Also, the cars used a vapor separator at the back.(right in front of the tank on E-body cars) That separator isn't designed to have raw fuel flowing through it on its way back to the tank. You could possibly bypass it and add an extra nipple to the sending unit for fuel return.

If the stock fuel filter has a 3rd return nipple factory then there should be a factory return line to the tank ?

It doesn't, I'm adding one in.


I got it all plumbed up today...I'll find out tomorrow if it works, or fails and hopefully it does so I can drive it to the Cruise-In Friday evening like I promised my kiddo I would.

If anyone see's anything dangerous, please let me know...The fuel line is NOT parts store variety, it's USCG approved line, and on the vapor line coming off of the filter, that is actually a 5/16 abrasion & fire resistant line (I use it in a lot of places). There's a specialty hose shop that caters to the Refineries and the Oil Field around here which is where I get my rubber products.

Just wanted to update, everything is working good so far.

Had I used the vapor canister, it would have filled with fuel rapidly as the vapor separator coming off of the filter does discharge liquid fuel.

So did you run the vapor line back to the tank or do something else?

I used the factory line from the tank that ran right alongside the supply line and just disconnected it from the vapor canister and plumbed the vapor separator onto it.

That was the vent for the tank, how are you now venting it? Yes, it needs venting.

The Fuel Cap is Vented