How do i know which pipe is the inlet an which is the return from the fuel rail?

One is connected to the regulator if that makes a difference?

as far as i know the return will have the regulator and will also be smaller in diameter

[Edited on 17/9/09 by l0rd]

fuel regulator will be at the 'end' of the fuel rail. so, thats the outlet/return end

Yup. The t'other end to the regulator is the "in"

Thats what i thought but wasnt sure.

Cheers