Electric Fuel Pump Power Source

[FuzzyDriver]

Where should an electric fuel pump be powered from? When I got my Comet, it was connected to the ACC stud on the ignition switch. Where should it be powered up, so it only runs in the ON position? The C position usually just powers the ignition in ON.
Can it also handle the fuel pump. And would connecting them cause radio interference?

[A/FX]

Where should an electric fuel pump be powered from? When I got my Comet, it was connected to the ACC stud on the ignition switch. Where should it be powered up, so it only runs in the ON position? The C position usually just powers the ignition in ON.
Can it also handle the fuel pump. And would connecting them cause radio interference?

There are a number of ways to wire in your fuel pump. It should always have a switch in line so that if there was an under hood fire the pump could be shut off. Don’t rely on the ignition switch as a shut off.
Here is how I recommend you wire it:
https://www.enginebasics.com/Advanced%2 ... relay.html

This is how I have mine wired, except I added a push/ pull switch in line because I also have a high volume mechanical pump on the engine:
http://www.how-to-build-hotrods.com/ele ... -pump.html

Use good quality wire and terminals, I use uninsulated terminals and shrink tube installed with a professional type ratchet crimping tool. I never solder terminals in an automotive application.
Jim

[FuzzyDriver]

Thank you for the detailed reply and links. Do you have the 5-pin relay (the one in the how-to-build-hotrods schematic) or the 4-pin relay (specified engine basics)?

I've just got a stock 200-6 so I have no idea why one of the previous owners installed an electric pump and blanked off the hole in the engine.

I just measured the current; it's 1.06 A. Must not be much of a pump back there for the draw to be only ~12 Watts. It's a noisy bugger, but maybe it's using the gas tank to propagate the noise into the trunk - that's where it's coming from. Do you get lots of buzzy noise from your trunk? That's a beautiful Comet you've got, BTW.

[A/FX]

Thank you for the detailed reply and links. Do you have the 5-pin relay (the one in the how-to-build-hotrods schematic) or the 4-pin relay (specified engine basics)?

I've just got a stock 200-6 so I have no idea why one of the previous owners installed an electric pump and blanked off the hole in the engine.

I just measured the current; it's 1.06 A. Must not be much of a pump back there for the draw to be only ~12 Watts. It's a noisy bugger, but maybe it's using the gas tank to propagate the noise into the trunk - that's where it's coming from. Do you get lots of buzzy noise from your trunk? That's a beautiful Comet you've got, BTW.

I have it wired as shown on the drawing, I believe I used a five pin but did not use 87a.
I have a bank of relays mounted under the dashboard just below the glove box that control all of the high draw accessories. I do not hear or feel the fuel pump when it is turned on but the engine and exhaust noise could be drowning it out. I have a Carter pump mounted in rubber, it feeds a canister type fuel filter mounted on the frame rail just in front of the LH axle tube. Remember an electric pump is designed to push fuel not suck fuel, it needs to be mounted lower than the outlet on the tank.
Jim

[SASSY]

Jim could you explain why no solder?

[A/FX]

Jim could you explain why no solder?

This subject draws its share of controversy when discussed.
I have read quite a bit on it and the consensus is that solder will make the connection brittle, it also wicks up the wire and takes away some of the flexibility. Aircraft technicians are adamant on using a crimp connection.
A professional ratchet type crimping tool and uninsulated terminals are the preferred method. Using heat shrink tube over the terminal or joint insulates from shorting out and moisture. I have wired a number of cars without solder, I invested in a quality crimp tool for terminals and another for battery type cables. I also use fine strand copper conductor welding cable for all my battery cables. (Gauge depends on length and draw)
Right or wrong I have joined the crimp camp and it has worked out well.
Jim

[SASSY]

Thanks Jim. You being in the "crimp camp" gives it legitimacy in my book!
I've never seen a ratchet crimper, just those plier ones and the insulated terminals which I don't like.
I'll have to look into that crimper.

[Caveman49]

Great info Jim. What crimpers do you use, I’m looking for a good set, but not the most expensive ones. Trying to avoid anything certified through c-h-i-n-a, you know what I mean…..

[A/FX]

Great info Jim. What crimpers do you use, I’m looking for a good set, but not the most expensive ones. Trying to avoid anything certified through c-h-i-n-a, you know what I mean…..

Here is the crimp tool, it comes with one set of dies of your choice. Multiple types of dies are available for different terminals. I have dies for uninsulated, insulated, pin, flag, and spark plug terminals.
Jim
https://eclipsetools.com/default/300-132.html

A couple of pages of dies:
https://eclipsetools.com/default/cable- ... t_limit=36

[Caveman49]

Thanks Jim!

[tomb22]

Here is another very good crimper that I used for 32 years as an electrician. It's made by Thomas & Betts here in the states.


I would also suggest a inertia activated fuel pump cut off switch which is inline with the pump feed wire which cuts off the fuel pump if your in an accident. Very easy to install.

Tom

[A/FX]

Here is another very good crimper that I used for 32 years as an electrician. It's made by Thomas & Betts here in the states.


I would also suggest a inertia activated fuel pump cut off switch which is inline with the pump feed wire which cuts off the fuel pump if your in an accident. Very easy to install.

Tom

That is also a great tool, I have the same one. I carried the T&B crimper, a Klein Linesman, a “dykes” side cutter, needle nose, and a couple of good screwdrivers in my pouch. ( not an electrician but a maintenance tech for 20 years)
Jim

[FuzzyDriver]

I have it wired as shown on the drawing, I believe I used a five pin but did not use 87a.
I have a bank of relays mounted under the dashboard just below the glove box that control all of the high draw accessories. I do not hear or feel the fuel pump when it is turned on but the engine and exhaust noise could be drowning it out. I have a Carter pump mounted in rubber, it feeds a canister type fuel filter mounted on the frame rail just in front of the LH axle tube. Remember an electric pump is designed to push fuel not suck fuel, it needs to be mounted lower than the outlet on the tank.
Jim

Well, here's an issue I identified today and it reminded me of this post of yours immediately, LOL:

"...an electric pump is designed to push fuel not suck fuel"

I found the gas cap a previous owner put on my baby is non-vented. Once it draws a vacuum on your gas tank we're looking at the equivalent of the pump being mounted up to 30 feet above the tank (exact value depends on how much air was in the tank when you turned the pump on and how long you draw the vacuum on it). I can't wait to hear the difference in pump noise when I get the right, vented gas cap!