What would cause a fuel pump to be this noisy?

[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?

[Aidan]

sounds like pressure valve not doing it's job and pump running flat out to keep up pressure
there's a lot of posts about noisy pumps on subaruvanagon forum

[KarlT]

Thanks for reply. Will look into it!

[big red bus]

could it be possible the tank outlet is partially blocked and the the pump trying to draw fuel.this could be running prob as well. Try using a jerry can as the fuel tank and run it from the can. this would elimanate the fuel tank.

[KarlT]

Right. I've disconnected the fuel hose & connected a hose-pipe straight to the fuel-filler.
Ran pump off spare battery. Let it run for about 10 minutes. Pump buzzed but wasn't real loud & I'd say pumped about 2/2.5 litres a minute.
All in all thought it was normal.

[Aidan]

have you got a fuel injection fuel tank and have you fitted new big bore lines ?

[KarlT]

Injection tank....Yes.
Bigger hoses....... No. Pump outlet & filter in/out's are same size as previous. So unless I change that as well, bigger hoses shouldn't make any difference.

[Aidan]

filter before the pump ? they don't like that, it causes cavitation

talk to Richard, he wants to hear from you anyway I gather