HELP: Which is supply and which is return?
 

On a '97 3.0, which line at the fuel injector rail is the supply line and which is the return? The engine is not in a vehicle, so i can't trace the lines back to the filter or tank. I'm thinking that the line coming off nearest the fuel pressure regulator is the return line, but is this correct? Thanks.

if its the same as my 99 and 04 the fuel line comes in from the drivers side and hooks the the fuel rail on the passenger side. Its to the passenger side of the intake.

in line should have a fuel pressure regulator or schraider valve on it ,,, return doesnot have anything that i know of

Thanks for the replies, but I believe our trucks are different. Mine has two fuel lines, one from the tank and one to return excess fuel to the tank. In '98, they went to a single line, supply only, no return.

I have two lines, one goes to the fuel rail that runs under the intake plenum between the two engine banks. The other line comes off the fuel rail that is on the passenger side of the engine where the fuel pressure regulator is located.. Can anyone tell me with certainty which is

I seem to remember they are different diameters. The large one is supply and the smaller one is the return.

They are two different sizes, as you said, and the larger one is the one I was guessing was the supply. That is what I will go with. Thanks for your reply.