In tank fuel pump

[M@H]

Hmm an interesting read, thank you!

I think I will simply plumb the vent line from the pump assembly through a one way valve and a fuel filter (just to make sure nothing gets sucked in). and then to air somewhere.

I am wondering what happens on a hot day with a full tank of fuel?

The vent pipe on the pump assembly terminates (or intitiates depending on
your point of view) quite low down, so potentially below the surface of the petrol - it actually joins the rail return pipe in a little plastic body and has one exit.

On a hot day, potentially the expansion of the tank would be pushing fuel back up this pipe (vapour if the fuel level was low, fuel if the fuel level is high), so the no return valve is surely essential to prevent this and hold any back pressure in the tank (or let it leak out at the filler cap).

Perhaps I'm over thinking this one

[popout]

Well, finally plucked up courage to weld the Subaru pump into the bay tank!

[popout]

Just to resurrect this thread, as I'm now connecting the fuel system up...at last!
Connections on the pump...Above photo, top one, pump feed to engine, middle, return and bottom, vent, is this correct?

On M@H photo of the pipes on the engine...Top...fuel in, middle...Return, and bottom vent, is this correct? And, whats the round thing on the return pipe? Don't remember seeing one on mine and haven't got one...Do I need one?

Now, the vents on the Bay window tank. Should I tee the pipe that's in the engine bay into the Subaru vent, or what do I do with the Bays open pipe?

hope I haven't confused you too much
Cheers Tim