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Old 04-06-2020, 06:22 PM   #1
tp79557
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Default Electrical Fuel Pump Wiring??

Hey guys,
So for the time being, I’m having to wire up a fuel pump since I have Weber carb on my car (came that way when I got it). Im running a 6 volt system, so the low pressure pump I have will work, but how would I go about wiring it? I would like for it to run only when the key is on. I can’t run it off the terminal block, cuz it’s hot all the time. Would I be able to get power from the key switch? I’m open to suggestions. I’m eventually going to go back to an original Zenith carb and get rid of the pump, when time and money allow. For now, this is what I’ll have to use. Thanks for any help!
Trent
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Old 04-06-2020, 06:30 PM   #2
Jim/GA
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Default Re: Electrical Fuel Pump Wiring??

You can not take power off of the key switch if you are still using the pop-out key switch. Because the previous owner went to a Weber carb, it is pretty easy to assume that they also got away from the pop-out switch, but only you can confirm that.

Once you see that you have a basic key-operated on/off switch, then you need to investigate how it is wired.

If wired per original Henry Ford, the power feed to the coil is "hot" all the time and the key interrupts the connection between the other post of the coil and the points inside the distributor. If that's the way it is wired now, you can't take the power that you need for the fuel pump off of the key switch.

The "other way" to wire it up is to have the key switch turn the power feed to the coil on and off. The other post of the coil connects directly to the points inside the distributor. This is the more conventional wire to wire ignition on a car. If this is what you have, then you can take the power you need from the switched terminal of the key switch.

If not wired this second way, you will need to rewire it to be this way, then proceed.

Good luck with it. Let me know if you have any questions.
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Old 04-06-2020, 06:53 PM   #3
Mulletwagon
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Default Re: Electrical Fuel Pump Wiring??

Some caution worth noting. Electrical fuel pumps are normally wired through an oil pressure switch (or computer sensing rpm) on more modern cars and boats to ensure the pump only runs when there is oil pressure (the engine is running). The reason is in a wreck or fuel line failure the pump will not run avoiding raw fuel being pumped into the engine compartment. Not sure wiring to the down stream side of the coil would work since this would in essence ground the coil and make the breaker points nonfunctional. Might consider an independent switch with an ON light since the instal is only temporary. Probably best to bite the bullet and instal a Zenith carb.
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Old 04-06-2020, 09:08 PM   #4
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Default Re: Electrical Fuel Pump Wiring??

One option for a fuel pump safety switch can be found here:


The site does list a 6 volt model. I do not know if positive ground is an issue but a work around can usually be done if necessary.

Stay safe,

John
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Old 04-06-2020, 09:30 PM   #5
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Default Re: Electrical Fuel Pump Wiring??

On my '55 Ranchwagon I used a Ford Inertia Switch used in most Ford Models. It doesn't care if it is 12v or 6v, + or - ground. Similar to this one. https://www.ebay.com/itm/FORD-INERTI...0AAOSwe-hee7bu
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Old 04-06-2020, 09:30 PM   #6
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Default Re: Electrical Fuel Pump Wiring??

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Quote:
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One option for a fuel pump safety switch can be found here:


The site does list a 6 volt model. I do not know if positive ground is an issue but a work around can usually be done if necessary.

Stay safe,

John
I have one of these, just waiting for me to install it.
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Old 04-07-2020, 10:32 AM   #7
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Default Re: Electrical Fuel Pump Wiring??

Quote:
Originally Posted by John View Post
One option for a fuel pump safety switch can be found here:


The site does list a 6 volt model. I do not know if positive ground is an issue but a work around can usually be done if necessary.

Stay safe,

John
Those appear to be designed for negative ground only, but you can contact the vendor, [email protected]. Though it's pretty easy to convert to negative ground if you need to.
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Old 04-07-2020, 10:38 AM   #8
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Default Re: Electrical Fuel Pump Wiring??

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Originally Posted by Badpuppy View Post
Those appear to be designed for negative ground only, but you can contact the vendor, [email protected]. Though it's pretty easy to convert to negative ground if you need to.
I suggest that you source and install an inertia switch from a late model Ford vehicle, this switch will cut power to the electric pump in case of an accident.
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Old 04-07-2020, 10:43 AM   #9
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Default Re: Electrical Fuel Pump Wiring??

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I suggest that you source and install an inertia switch from a late model Ford vehicle, this switch will cut power to the electric pump in case of an accident.
I agree... see post #5.
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Old 04-08-2020, 10:19 AM   #10
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Default Re: Electrical Fuel Pump Wiring??

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I suggest that you source and install an inertia switch from a late model Ford vehicle, this switch will cut power to the electric pump in case of an accident.
Capital idea. Just make sure it doesn't leave you high and dry after hitting a bump in the road. Some earlier ones could do that. Later ones need to be connected into the car's computer.

Or you could just live in the 1950's and roll the dice.
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Old 04-08-2020, 10:50 AM   #11
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Default Re: Electrical Fuel Pump Wiring??

It seems that a broken fuel line will dump fuel to the engine compartment no matter if you have a fuel pump or not. That being said, I wire mine like Jim Cannon describes in post 2.
Safety is important, but you can't cover every eventuality and still enjoy the hobby.
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Old 04-08-2020, 11:55 AM   #12
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Default Re: Electrical Fuel Pump Wiring??

Quote:
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Capital idea. Just make sure it doesn't leave you high and dry after hitting a bump in the road.
They do have a reset button if that ever happens.
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Old 04-08-2020, 12:17 PM   #13
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Default Re: Electrical Fuel Pump Wiring??

Quote:
Originally Posted by Badpuppy View Post
Capital idea. Just make sure it doesn't leave you high and dry after hitting a bump in the road. Some earlier ones could do that. Later ones need to be connected into the car's computer.

Or you could just live in the 1950's and roll the dice.
This has happened to my son twice now. First time was while he was in high school in a Bronco 2, more re recently in his Ranger pickup. That last one cost him a$500 tow, plus he missed the car show he was on his way to.
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Old 04-08-2020, 01:08 PM   #14
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Default Re: Electrical Fuel Pump Wiring??

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This has happened to my son twice now. First time was while he was in high school in a Bronco 2, more re recently in his Ranger pickup. That last one cost him a$500 tow, plus he missed the car show he was on his way to.
My '89 Super Coupe has one. Does your son know how to locate it and reset it IF it falsely trips, which I have never had happen since I bought the car new in '89. Sometimes they are hard to find.
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Old 04-08-2020, 01:11 PM   #15
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Default Re: Electrical Fuel Pump Wiring??

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My '89 Super Coupe has one. Does your son know how to locate it and reset it IF it falsely trips, which I have never had happen since I bought the car new in '89. Sometimes they are hard to find.
He does now!
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