Fuel Pump Noise

rjes · Posted: Thu Apr 30, 2009 8:38 pm Post subject: Fuel Pump Noise

Two customers with T25's have got in touch with exactly the same problem with their fuel systems within two days of each other. Both proved to have the exact same problem. It's somehting which I have not come across before - excessive fuel pump noise which changes or comes and goes as you drive. Both had 2WD's, recently converted to injected Subaru power from carburettor wasserboxer. One also reported the engine being unwilling to go over 5000 rpm, but not a dead limit at a repeatable rpm like a rev limiter.
Both had their pumps rubber mounted in a sensible way, yet the noise would vary as you drive. Neither had changed the tanks as part of the conversion, and between them they had tried numerous rubber mounting systems, a used VW pump, a new Bosch pump and an aftermarket pump, all with no effect. We came to the conclusion that it must be crap in the tank sloshing around and occasionally blocking the suction strainer, with the noise being the pump starting to cavitate due to inlet blockage, and the rpm limit being fuel starvation.
I came up with a quick check to prove it. Remove the outlet hose from the tank, dangle it into a clean can of petrol, start the engine, and see if the pump quietens. In both cases they did, and the owners chose to solve the problem by replacing the tank rather than cleaning it out. Replacement also gave them the chance to swap to the injection tank with it's bigger hose fittings.
Hopefullybthis will be of use to others with the same symptoms. If you have this problem, you need to get it fixed, as pump cavitation will greatly reduce the life of your fuel pump.
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com

hansend23 · Posted: Sat May 02, 2009 4:34 pm Post subject:

you know,mine does this.i have the in and out right next to eachother.
on the bottem of the tank.ill have to check it out.
it sounds like its cavitating.
_________________
just do it!

gerrelt · Posted: Sun May 03, 2009 11:55 am Post subject:

I've got the exact same thing with my Alfa conversion. I didn't change the tank also. I sometimes hear the pump buzz too. I always carry a spare fuelpump on long journeys, because I suspect the shorter lifetime of the pump with my fuel line setup.

Now I am contemplating a switch to a subaru in-tank fuel pump. But, my fuel system works at around 4 bar ( if I remember correctly) and I don't know how much the subaru pumps deliver? I know the pressure is regulated by the pressure regulater (... Laugh Out Loud

) , but I don't want to over-pressurize the regulator.

Could somebody tell me what kind of subaru in-tank pump would be suitable for me?
_________________
homepage

VolksRomeo 13033 S 1.4 IE
(VW 1303 S with Alfa Romeo 33 1.4 IE engine)
_________________

hansend23 · Posted: Thu Jul 09, 2009 3:33 pm Post subject:

my fuel pump is noisy again.i changed the filtersmy pump is only noisy when the engine runs.
when you turn the key on and off it just cycles with no noise.
only when its running it makes noise...
stock vw fuel pump from a 76 FI bug. its like a t25.FI pump.
91 ej2.2. vw put the return right next to the feed on the FI bugs so thats what i did.i also have the vw filter before the pump like vw did and the scooby one at the engine.both are new.is that too much?
sometimes its quiet but not now.
any magical info?
_________________
just do it!

B4Tfink · Posted: Thu Jul 09, 2009 5:03 pm Post subject: noisey fuel pump

I had this issue when i installed my ej25 originally. i had a new tank with 8mm out and lots of rubber mounting on a rjes pump (bolt though chassis rubber washer under head of bolt, eleccy tape down the thread, inch block of rubber between chassis and pump hoop support and 2mm thick rubber between hoop support and pump) this made lots of noise i can only assume cavitation and not vibration due to my over engineering of the pump holder.
Since changing to a new 12mm outlet the noise in the cab seems slightly better but from outside very much quieter.
I am now just waiting to compare normal pump noise with another converstion to comfirm this fixed it..
However i have noticed that it runs much smoother at high revs with the new 12mm tank so am under the impression this made a lot of difference. also i am no longer concerned it may be running lean..
If theres anyone with a scooby conversion in the bordon/farnham area i would be interested in a listen to your pump to compare (a t25 ej25 would be ideal..

)