Well thanks to the kindness of JC he allowed me the use of his fuel pressure tester. Here’s the readings.
Motor off and prime with key – 40 psi
Motor off and prime finished – 37 psi
Motor at idle vacuum line on regulator – 50-55 psi
Motor at idle vacuum line off regulator – 50-55 psi
So fair to say a faulty fuel pressure regulator. Tried a second hand regulator from jc and voila – she works.
I’m hazarding a guess here but is this like carburetors where the orings etc dry out if they haven’t had fuel running through them for a while? the fuel pump and regulator were out of action for a few months so I’m guessing that’s it.
Btw – there was no fuel leaking from the regulator out the vacuum line and you could still suck on the vacuum line and it would hold pressure. So you don’t always get the obvious signs of a failed regulator.
