Fuel Pump Location

[Guest ant.b]

hi

i have a low pressure pump that feeds a swirl pot tank that then feeds my injection pump, does the low pressure one need to be fitted below the main tank or can it just go above it in the boot ? just checking as i ve some probs with what seems to be an air lock ,and the low pressure pump not sucking from the tank , i have tried a spare pump and its the same problem , its mounted about level with the top of the tank at the moment on the underside of boot floor .

suggestions welcome

ant

[Guest chris brown]

hi

i have a low pressure pump that feeds a swirl pot tank that then feeds my injection pump, does the low pressure one need to be fitted below the main tank or can it just go above it in the boot ? just checking as i ve some probs with what seems to be an air lock ,and the low pressure pump not sucking from the tank , i have tried a spare pump and its the same problem , its mounted about level with the top of the tank at the moment on the underside of boot floor .

suggestions welcome

ant

Low pressure pumps will normally pump air so can be positioned above the tank unlike the high pressure ones which very quickly give up if not pumping fuel when powered up.

[Guest ant.b]

Low pressure pumps will normally pump air so can be positioned above the tank unlike the high pressure ones which very quickly give up if not pumping fuel when powered up.

 

hi chris

so im guessin its ok where it is then , and could just be the pump on its way out ? maybe i have 2 bad pumps then , will just have to try another pump

cheers

[steve in stockport]

Hi Ant

 

what low pressure pump are you using, is it up to the job of feeding that cossie beast?

 

i'm using a facet solid state fast road pump betweem tank and swirl pot and its mounted on the underside of the tube that curls over the diff, so its about level with the top of the diff, possibly a couple of inches lower than yours.

it also has to be at a slight angle to help get the air out

 

Steve

[Guest Dan_Beeston]

I'm also using a Facet solid state pump, mounted on the underside of the boot floor.

 

No issues with it so far................

[Guest ant.b]

i presume the pump is up to it as you can hear it tick as it fills the swirl pot , and it only ticks slow , and speeds up when the pot emptys , but dont hear it very often runnin fast , so ive temp fitted my pump in the boot so ive got easy access and blocked off a return from swirl pot to tank so i can see if this has any affect , goin to give it a trial run to donny on sunday so we shall see what happens , aquired another spare pump of steve cheadle so i should be ok if it packs in

[Longboarder]

Check with the pump specifications as the maker will usually tell you how far the pump can be sited above the tank. The Facet solid state ones will dry prime 0.3metres above the fuel surface, the cylindrical facets like the red top etc, 0.6metres.

 

Assuming you have the high pressure return into the swirlpot then the lifter only has to replace what the engine uses. If you get 10 miles to the gallon at 120mph that gives it 5 minutes to lift a gallon. The basic facet lifts 25 US gallons in an hour but that's only 20.8 UK gallons, that's roughly three minutes to lift a gallon into the swirlpot so you would have to be giving it a fair bit of welly for the swirlpot to run dry.

 

To reduce the workrate/clicking it is worth putting a restriction down to max 2mm in the swirlpot to tank return pipe. Air/vapour can still leave the pot easily but the pump will be able to work slower. Good practice to filter the fuel before the pump and that should allow longer pump life and a 1mm return hole to the tank for even less clicking.

 

I would check there is an air inlet to the tank to prevent a vacuum building up and nothing blocking the pump inlet tube to restrict flow. You can test your pump by taking the outlet (extended?) to a gallon can, powering the pump and check it takes about three minutes to fill the can! Don't smoke while doing this!!!

 

Nigel