fuel presure problem (PLEASE HELP)
Turbo Mini Forums

Right i tryed start up for the first time today and everything read fine on the fuel presure guage set at 4psi. After a few failed attempts to start the new fuel pump started making a higher pitched pumping noise and the fuel presure shot right of the guage.

So far to try and get the presure back to 4psi i have...

-Checked all plumbing is correct
-Tryed to adjust on regulator with no joy
-tryed taking pipe from plenum to regulator off to see if diapham is split and it appears to be fine no leaks
-Disconnected return fuel line from tank and put into fuel can and tested and is all fine no blocks and fuel returning
-Fuel lines are 8mm so not to small bore
-Taken regulator to bits and given visual check and clean and nothing appears wrong.

sorry to post another presure problem but i have read all the others and still im stuck please help!.

Yes i moved to the darkside

Instagram @jdm_brett

Could poss be this but i dont think so as there was only a small flow of fuel coming through and the pipe was more than big enough to deal with this i also had fuel cap off to release presure and still made no differance.

when i had this exact problem it turned out to be the t-peice gauge adapter i was using to mount the fuel pressure gauge..i mounted mine just before the carb and because id screwed the gauge in so far it was restricting the fuel flow...

Edited by Bman on 4th May, 2010.

funny you mention this bman i also have a draper inline fuel guage plumbed in, just before the carb which is also on a plastic t peice maybe i have crunched the plastic, but this still dosnt explain why the presure is this high after ther regulator?.

the return pipe should return quite abit of fuel to keep the pressure down imo

i would investigate the small flow of fuel out the return connect a short length of pipe from the regulator straight into a bucket and try again, if its the same result look at the regulator itself

Yes i moved to the darkside

Instagram @jdm_brett

Brett it was a fair amount of fuel not i dribble i am quite sure this is good. Could it be anything to do with the carb as i tryed to rebuild it myself?.

Edited by Brett on 4th May, 2010.

Yes i moved to the darkside

Instagram @jdm_brett

i have double checked fuel return today and there is a good flow there so i can only assume the regulator is fooked, i have also bought a 10mm metal t peice to replace the small plastic one for the presure guage to try and help flow.

Thanks for your help so far!.

I think i might have found the problem but i cant prove until i have new t peice on.

I disconnected the fuel lines from my foam filled alloy tank again and tryed blowing directly into tank outlets one at a time.

On the tank outlet i had my return fuel line going to i blew down and it blew fuel straight out of the other tank outlet.

On the other tank outlet which i have my pump on i blew down it and i just got bubbling sounds.

does this mean i have inlet and outlet mixxed up on tank as there is no markings?

can anyone tell by looking at my tank weather the two outlets are flow and return as i think this maybe the cause of my problem.

Maybe there is not a return in which case im unsure of what the other outlet is?.

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Sounds like you could have them the wrong way around to me.

Is the tank vented?

If something is worth doing, it's worth doing half of.

thats what i thought, the tank is not vented it just has the two outlets

One will be an outlet and one will be a breather

Take the cap off and try it
It sounds like you might be pressurising the tank

Edited by Nic on 4th May, 2010.

Good call nic.
Could he use a vented cap or I suppose get the tank modded for a return.

If something is worth doing, it's worth doing half of.

An outlet for an external efi pump on the top of a tank.....thats funny


Now seriously....catch a grip. Even if its dipped, its a bloody stupid design.

Edited by stevieturbo on 4th May, 2010.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

sorry didnt reslise i was ment to know that on a first time build! guess thats what this forum is all about?

efi pumps do not self prime.

The pump must have a good ample gravity fed supply of fuel.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

ok thanks in process of getting another outlet tigged onto tank low down.

And always ensure that there is an adequate reserve of fuel at all times for an efi pump

Either via an internal collector, a sump, or a swirl tank.

Never simply plumb an efi pump into a large open tank....unless you intend keeping it more than half full.

On acarb engine you'll get away with it better than an actual fuel injected one...but the pump continually seeing air will kill it in no time.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will