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Fuel pump
Jcb198 - 11/9/18 at 10:02 PM

Hi I gave just bought a my Indy with a 2.1 pinto. I was wondering if any one knows how the electric fuel pump should function. It is wired to the 12v switched some comes on before you start to prime the carbs. If you do not start the engine it continues to run and eventually you can see some fuel dripping from the carbs. My question is obviously if the engine is running this is not a problem but should the pump for example stop when the correct pressure is reached. Or do they just run continuously. Obviously it maybe the pump is to high pressure and is pushing past the floats etc but the car runs great so seems fine when running.
Any help would be great


melly-g - 11/9/18 at 10:11 PM

It should slow down and almost stop when the floats shut the valve!
You need to get the pressure checked maybe the pump is overwhelming the float valves?
What carbs? If it's bike carbs they need a very low pressure pump!

mcerd1 - 11/9/18 at 10:11 PM

first what kind of carb's and pump have you got ?

bike carb's use/need specific pumps that self-regulate the pressure (nothing too special, just he OE pump from a bike with carb's)

[Edited on 11/9/2018 by mcerd1]

Jcb198 - 11/9/18 at 10:38 PM

I have twin 45 Webbers on a 2,1 pinto. No idea what pump I have I can pull it off the ad tomorrow. I assumed it should stop or slow. Maybe I need a regulator. Or an air leak or the floats not closing off. I could test by blocking the fuel pipe and seeing if it stops or slows

Thanks again

snapper - 12/9/18 at 06:00 AM

Pressure regulator would be the norm as Weber’s only need 2.5 to 3.5 psi

cliftyhanger - 12/9/18 at 06:37 AM

I ran my webers at 1psi, after I kept getting flooding when doing autosolos. Sadly didn't help, but ran no issues at all. Carbs don't need any real pressure at all, if fuel gets to the carbs with enough flow all is well.

So, I suspect the pump you are using is just too high a pressure, and a regulator near the carbs set to 2psi should sort it all out.

Jcb198 - 12/9/18 at 07:34 AM

Any suggestions on a regulator. I assume it has a feed that loops back to the tank to for the excess flow / pressure. The car runs great but as just worried maybe the pump shouldn't keep going if the engine isn't running

cliftyhanger - 12/9/18 at 09:34 AM

sytec ones are OK, malpassi better but more cash...
No tank return, they just fit inline.

Jcb198 - 12/9/18 at 09:52 AM

How does it vent the excess pressure if there is no return. Would it not cause the fuel pump probs otherwise

cliftyhanger - 12/9/18 at 09:11 PM

never thought about it. but they do work, and don't cause an issue.

melly-g - 12/9/18 at 09:36 PM

Pump will just slow or stop like it's at high pressure,
You could always put a standard mechanical pump on the engine, I ran my pinto like that for while without any issues it had webers on it.

[Edited on 12/9/18 by melly-g]

rusty nuts - 14/9/18 at 12:19 PM

Fact type pumps don't slow down and stop like the old SU pumps, think they may be as high as 5 PSI.

02GF74 - 14/9/18 at 05:47 PM

There is a way to wire up a pump using feed from the alternator, means pump only runs when the engine is running. Obviously needs some electrickery to power it prior to engine running, more of a safety feature.