[beatnavy]

I used this diagram for my 1.7 fuel line replacement, and I think it's pretty accurate. There's always potential for variation based on mods made by a PO (like moving a fuel pump location), but functionally it is correct.

In terms of the "Y" connector, I think this is what happens (somewhat speculation on my part): the fuel pump is rated to deliver several times the volume/pressure of fuel actually required, so there's a fairly constant return flow back to the tank. The fuel can only flow in one direction (based on several things probably, including fuel pressure regulator up in the engine bay). Because of this it's pretty straightforward to see how the fuel on the return line, coming back from the engine by, is pulled toward the tank with the other fuel that wasn't needed on the delivery line.

Pretty bad explanation, I am sure. I initially struggled with it conceptually too (and evidently still do).