[AK]

if you have connected the pipework the right way round, I am puzzled.

It is quite easy to get them wrong.

One is a feed to the pump, and the other a return from the pressure regulator - if you get them the wrong way round, it wont run as there is no pressure to the injectors - only to the wrong side of the pressure regulator.

Pressure regulator is on the throttle body, so not that I think.

Alan