At tickover when I switch the headlights on the fuel pump slows down. The headlights are constant brightness through revs, same when I switch other stuff on/off. Is it the fuel pump wiring? It gets it's 12v via a relay, but otherwise directly connected to the battery. The relay maybe? Or just nothing to worry about? I can't tell if the pump speeds up again when the revs increase, it gets too noisy to hear it. I suppose I should check fuel pressure with lights and other stuff on/off.
What voltage are you getting out of the alternator? It may be struggling to keep up. Fuel pressure check would also be worthwhile like you say. My new alt and reg gives 14.5 volts without lights in. 13.8 with.
