Wiring an electric fuel pump

grumppyoldman

grumppyoldman

Well-known member
i had my electric fuel pump wired through the ignition switch when I first installed it, but you guy's said it might not handle the amps. I put a toggtle switch under the dash knowing I would probably forget to turn it off when stopping, and sure enough that's what I did. It stayed on for about 10 minutes before I thought about it, and turned it off. There is a 10 amp. inline fuse from the pump that was included with the pump. Do you still think the ignition switch would be harmed? This is a 6 volt system on my 41 Ford. Al
 
Why not use a relay? The relay allows full current flow and the ignition switch is only providing the relay trigger current.
 

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I have two old Fords with electric pumps wired through the ignition switch and a shut off switch. Both have been converted to 12 volts. I have had no electrical trouble with them. These Fords have been driven on long trips in hot weather with no trouble. These pumps don't draw much current.
 
Thanks for the reply's, I think maybe the relay will serve the purpose and not burn out the old switch. I use a starter relay on my tractor for the glow plugs and it stopped burning out the ignition switches and I didn't even think about doing the same on the fuel pump. DUH Al
 
You should also consider an electric fuel pump safety switch, as outlined in the July/August, 1999, V-8 Times. The last thing you need is a electric fuel pump feeding a fire in the event of a crash.
 
Always a good idea. I use the 5.0 Fox body mustang ones just because I am familiar with them.
 

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Yes. On the mustangs it is mounted in the trunk, right where you open the trunk lid. But you can mount one about anywhere.
 
If the pump is rated correctly, it shouldn't burn out a wire or switch. It will drain the battery.



Relay or a switch with a light. I would think having it connected to the shut of (power or coil feed) of the ignition switch it would turn off when the engine is off. Otherwise coils would burn out.


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That's what the relay trigger connects to, the ignition switch. The pump via the relay is turned on and off by the ignition switch. This off loads the current used to operate the pump from the ignition circuit. All modern electric fuel pumps I have worked with operate this way. The safety switch is a crash/rollover protection device that turns off the fuel flow (pump) in an accident.

Note: updated to clarify.
 
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Still not sure how turning the power off at the switch lead, powers a pump. Less it's connected to the lead power.



A inertia switch is a different animal. A good thing. Not that I worried to much with my model a and gas tank in my dash. nor used a electric fuel pump.


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i have a toggle switch mounted under the dash bu the door that will act as a kill switch. it's connected between the power source and the fuel pump along with a 10 amp fuse which is supplied with the airtex pump. Al
 
That only works if you are able to turn the switch off. In some accidents that is not possible. It would be rare to have such an accident, but they can and do occur.
 
grumppyoldman said:
i had my electric fuel pump wired through the ignition switch when I first installed it, but you guy's said it might not handle the amps. I put a toggtle switch under the dash knowing I would probably forget to turn it off when stopping, and sure enough that's what I did. It stayed on for about 10 minutes before I thought about it, and turned it off. There is a 10 amp. inline fuse from the pump that was included with the pump. Do you still think the ignition switch would be harmed? This is a 6 volt system on my 41 Ford. Al
Click to expand...



I also own a 41 and am curious why you had to add the electric fuel pump. Was the mechanical not able to do the job? I have a problem with mine that my check valves in my factory pump are not working as well as they should and the fuel drains back into the tank overnight. I think an add on fuel pump to prime the system may be something I will add if I can't get the check valves to work properly. It would only need to be used to get the car to start. Once it starts I have no problem starting it the rest of the day.
 
I think what i'll do is get a new mechanical pump, and use the electric one before start-up then turn it off aftter the engine is running. I also have a fuel pressure regulator and gauge between the fuel pump and carburator. It runs best at 2 1/2 3#. Al
 
When I used an electric pump I wired it to the accessory terminal on
the ignition switch. The small ball shaped ends on the triangle shaped
copper or brass contact plate won't carry much current with the small
contact area. I put the ball end on 2,000 paper and with a LITTLE pressure
move the ball ends on the paper until you get a good flat area on the ends
of the balls, don't go through the material. Before sanding I bend the balls
down slightly so when put back together it has a little more down pressure
on the contact surface. G.M.
 
the cup on the end of the fuel pump arm was turned back towards the firewall and was not pumping well, so I put the electric pump thinking I was taking some pressure off the cam an doing away with the electric pump. I don't know what the push rod bushing looks like, but there was only a piece of tubing in there and that didn't look like a very good bushing. Maybe something was missing, and that tube was supposed to have a bushing inside it, any thoughts? Al
 
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