1974 914 1.8 - Fuel System

[Chewable]

I replaced my fuel lines with Stainless Steel. I have about 8' of fuel injection rated fuel line. The engine and transmission were pulled and I hope to start putting everything back together tomorrow.

Pretty much the best diagram for how this is supposed to go back together is this one-
http://bowlsby.net/914/Classic/zTN_FI_Hose_FuelPump_1970-74.jpg

This is the only thing I have been able to find that looks like what I have going on below.
Is that diagram pretty accurate?

Why would there be that "Y" fitting to run the return line back through the pump?

[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).

[Dave at Pelican Parts]

The short version: The fuel pressure regulator bleeds off excess fuel (which is most of it) and sends it back to the tank. The fuel pump can also bleed off excess fuel if it needs to (which it should hardly ever need to do). That fuel also needs to go back to the tank. So the two of those lines are Y-d together in order to get the excess fuel back into the tank.

--DD