Hi all, I've just installed a Facet low pressure fuel pump and swirl pot in my car to feed the HP EFI pump to cure fuel starvation on fast right
handers. I can't believe how noisy this LP pump is! It's banging away like a jack-hammer. Is this normal? I can't believe anyone
would put up with this amount of noise constantly. I saw on a forum somewhere that an R1 motorbike pump would be good for this and really quiet.
I have Facet low pressure fuel pump too, and it is noisy most of the time. I have noticed that it gets quieter when tank is full , (or with lot of )
fuel. I am in process of relocating the pump so it sits much lower than tank bottom , have read that when pump is lotated to high , then it is noisy.
I looks like the case considering quieting with full fuel tank.
It's currently floating and is noisy as anything. I also have a full tank of fuel with the pump at the level of the bottom of the tank.
I'm not convinced it's priming properly but as it's a self priming pump how could I check?
If you put a restriction in the return pipe from the swirlpot to the tank it may quieten it down. Some have used 0.8mm MIG welder tips in the return
pipe but a piece of metal (I used brass) with a small hole will do the job. The return really only needs to allow air back to the tank in normal
circumstances. Just make sure that it is of a large enough diameter not to get pushed into the tank.
quote:Originally posted by Jed
If you put a restriction in the return pipe from the swirlpot to the tank it may quieten it down. Some have used 0.8mm MIG welder tips in the return
pipe but a piece of metal (I used brass) with a small hole will do the job. The return really only needs to allow air back to the tank in normal
circumstances. Just make sure that it is of a large enough diameter not to get pushed into the tank.
This makes a huge difference to the noise from the LP pump. I used a 0.8mm mig welding tip.
If you temporarily pinch off the return hose with a pair of pliers, you should hear the differance.
As Jed said the return is an air bleed, not a fuel return. I used brake pipe for mine.
quote:Originally posted by Jed
If you put a restriction in the return pipe from the swirlpot to the tank it may quieten it down. Some have used 0.8mm MIG welder tips in the return
pipe but a piece of metal (I used brass) with a small hole will do the job. The return really only needs to allow air back to the tank in normal
circumstances. Just make sure that it is of a large enough diameter not to get pushed into the tank.
This makes a huge difference to the noise from the LP pump. I used a 0.8mm mig welding tip.
If you temporarily pinch off the return hose with a pair of pliers, you should hear the differance.
As Jed said the return is an air bleed, not a fuel return. I used brake pipe for mine.
[Edited on 26-10-19 by 40inches]
I did try crimping the outlet pipe of the pump and it made a bit of difference. I guess they like having a resistance to pump against rather than
being free flow. I'm interested in the theory that the return is air only, is this a carb thing? Mines EFI and there is a flow of fuel in the
return line.
As above the reason it's thumping away is it can't build up pressure, are you sure it even needs a return? the old style ones for carbs I
used would only do a pump stroke when the pressure dropped to a certain level, so initially when you turned on the ignition it would thump away and
then slow or stop once the carb was full and then only stroke again when required which may only be a few times a minute. If it kept going it meant
you either had fuel or it was pumping fuel all over the floor cos your fuel lines fallen off...
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