so the pump should be grounded to the chassis/ battery? I thought that was bypassing the regulator as it worked on the earth?
I have the pump working at battery voltage all the time,

the sound is drowned out by the exhaust

its working off a relay which was the problem.
Ive swapped out the relay again.
Have grounded the pump direct and unplugged the regulator, from my understanding its the silver thing to the right of the battery and in front of the blue relay, which is the original r33 fuel relay.
the relay hasn't blown yet, but haven't really been able to give it the beens with the rain at the moment.
still not sure i needed the relay and wiring as from what you've said the voltage would have been upped simply by grounding the pump.
thanks