Power Source for Electric Fuel Pump

Shoebox

Shoebox

Well-known member
I did a search on this topic and spent much time reading about inertia, rollover, and oil pressure switches, toggle vs. intermittent switches, etc., all good information. BUT I just wanted to know, on a '51 car, is it best to pull power (from the ign switch) from the IGN or ACC terminals for an electric pump. Thanks guys.
 

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I draw power from the circuit breaker power input, have an inline fuse, and a relay trigger connected to the ignition switch.. This keeps all those amps from burning up your ignition switch while keeping the “on/off” factor tied to the ignition.
 
Fritz said:
I draw power from the circuit breaker power input, have an inline fuse, and a relay trigger connected to the ignition switch.. This keeps all those amps from burning up your ignition switch while keeping the “on/off” factor tied to the ignition.
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Fritz, you checked all the boxes on that install. I've used relays on other projects for lights & cooling fans. My 12v fuel pump does not draw a lot of amps but I'm thinking about a relay.
 
Like others have said, you really want it to only come on in the run position, so it automatically gets shut off when the ignition is shut off. That will keep you from accidently leaving the fuel pump on. You want to run it off of the ignition side of the switch.

Now if you're only using the eclectic fuel pump to only prime the system and then running it off of the mechanical pump, then you can hook it up to a push button switch that only sends power to the pump when the button is push in and held. If you're going to do that then you need an electric pump that turns off in the "open" position so the mechanical pump will still be able to draw fuel through it when it's not in use. Most electric pumps are in the closed position when they are turned off to keep the fuel in the line from draining back into the tank. If you look in the fuel pump catalog it will list each electric pump by the volume pumped, the pressure and if it is open or closed in the off position. There are only a couple of them with the low pressure for a flathead and remain in the open position when they are turned off. If are not running a mechanical pump, then you want a pump that closes when it's in the off position to keep the line primed with fuel.

This is important, choose a pump that puts out the pressure your carburetor needs. Do not choose one with too much pressure and then put a fuel regulator in the line to drop the pressure. I have had nothing but problems with those regulators getting stuck, turning off the fuel. It seems like the low pressure required for a flathead carburetor sometimes is not enough pressure to cause the regulator to open and you coast to the side of the road. It's better to just buy the correct pressured electric pump for the carburetor you're using.

You want an electric fuel pump and filter mounted as close to the tank as possible.
 
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When working on my 1999 F150, I was surprised at the number of relays on that truck.

I think they're on to something.
 
Here's the AC fuel filter I used. They have the picture upside down; the can is supposed to point downward like a Ford fuel pump does. I would not mount it like they are showing. AC must have started making them again because i could not order it 15 years ago. What's neat is the large Ford fuel filter that you will be able to get anywhere cheap should you need it. There is an in and out to it so makes sure it will work where you're going to put it, somewhere close to the gas tank.

https://www.amazon.com/ACDelco-GF62P-Professional-Fuel-Filter/dp/B000C9TU0U/?tag=atomicindus08-20
 
Thanks Shoebox. I think the only box I didn’t check is an inertia switch. But that’s on the list.

On relays, I’ve become a fan.
 
Just a bit of a follow up, I installed a 12v Facet, Posi-Flo pump. With the interior out, I ran the power lead along the driver side floor and dropped down through the floor right by the pump. With no engine in yet, I can't report on how it performs, however I had about 1/4 tank of older gas and I was impressed how quietly it pumped it out (went into John Deere yard tractor). We'll see how it works when I get it on the road.
 
Something else to consider, it's been suggested on this form to install an oil loss pressure switch in the circuit. reason being, if you flip over the fuel pump will not keep pumping fuel all over do to the lack of oil pressure. It's highly unlikely that happens, but it's a safety issue.
With that said, I have not followed my own advise yet.:confused:
 
 
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