Noisy as hell DJ fuel pump.

[KarlT]

Hi.
Have recently fitted a EJ25 engine into my 2.1 DJ.
Subaru isn't running right. Wants to stall on tick over but saves itself in the last second.
But old DJ fuel pump is now, as nosiy as hell. Was fine before conversion, tank removed.
Half tank of petrol.
Ignition on. Pump buzzes for 2 seconds, primed, pump stops.
Start engine & all seems fine (maybe odd miss-fire but hard to tell) pump is/maybe normal.
As choke comes off, pump gets louder & louder. Go round by the wheel arch & its louder that the engine.
Sat in drivers seat you can hear pump over engine noise.
Does go quiet as engine nearly stalls, for half a second, and then buzzing again as engine picks up.

What would cause a pump to be this noisy?

[slowcoach]

nothing to do with a subaru engine (wbx), but my electric fuel pump went very loud, caused by a clogged fuel filter. pump working too hard, pushing or sucking on petrol?