Electric fuel pump re-wire
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Junior User
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Electric fuel pump re-wire
I bought my 78 f150 with an electric fuel pump used to fuel the engine. Only thing I don't like is how they wired it in. The fuel pump gets power in the acc. mode. I don't like this because sometimes I want to listen to the stereo when I'm outside of the truck but I can't because the pump powers up. Is there a place on the 78 I can wire it to for key-on only power or, should I just tap in an on/off switch which can possibly also be used in the event of an accident.
Lead Driver
Joined: Nov 2000
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From: Albuquerque
I would use a relay with power from the battery.Use ignition hot to energize the relay. Mount the relay under the hood. You could use a fuse tap on the fuse box for a circuit that's only hot with ignition on. Use a large wire for power to the pump.
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Better yet is to hook it up to a oil pressure switch.
It doesn't power up until oil pressure reachs 5 lbs.
It will also shut the pump down when the engine stalls in case you're in a collision .........which a safety concern
It doesn't power up until oil pressure reachs 5 lbs.
It will also shut the pump down when the engine stalls in case you're in a collision .........which a safety concern
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Originally Posted by Mrcorey5
Mr. mil1on,does that work with a gauge and /or idiot light sending unit?
All it is is a switch.. Pressure hits 5lbs..the circuit closes ....the pump starts up and as long as the PSI is above 0..it will keep running.
see second item listed.
http://www.marineengineparts.com/sho...ml/page81.html
Last edited by Mil1ion; May 3, 2007 at 07:45 PM.
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The truck runs an aftermarket oil pressure unit. I notice the idiot light never lights up, even when just turning the key to the 'on' position so I'm not sure if it is still even functional. Where is the actual switch located?
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New User
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It Tees into where the sending unit screws in.
I did this with a 80's Cadillac going from EFI to carb.
I interrupted the ground wire and tied into that for grounding out at 5 psi.
It worked like a charm.
to see an illustration scroll 1/2 way down this page.
Picture #3
http://www.allpar.com/history/mopar/electrical2.html
I did this with a 80's Cadillac going from EFI to carb.
I interrupted the ground wire and tied into that for grounding out at 5 psi.
It worked like a charm.
to see an illustration scroll 1/2 way down this page.
Picture #3
http://www.allpar.com/history/mopar/electrical2.html
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Post Fiend
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From: Across from the neighbors
It is located on the back of the block just behind the intake manifold. If you have an aftermarket unit then it works off of oil pressure going to an analog gauge instead of electiral current.
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Originally Posted by crazyredneckanyhow
It is located on the back of the block just behind the intake manifold. If you have an aftermarket unit then it works off of oil pressure going to an analog gauge instead of electiral current.
Lead Driver
Joined: Nov 2000
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From: Albuquerque
For clarification, Dennis is talking about an aftermarket OP switch you add with a "T". If you turn over or whatever and the motor quits it will shut off the fuel pump. It's in addition to a relay and ignition on trigger.
Posting Guru
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From: Northeast Nebraska
Dont forget to mount the fuel pump lower than the gas tank, like on the frame and keep it as close to the tank as possible. Also its a really good idea to have some sort of bypass that recirculates back to the gas tank so the pump doesnt overheat while idling. Remember the pump pushes the same pressure no matter what the demand is from the carb. I have an electric pump on my 79. I added a fuel filter with 2 oulets. One goes to the carb and one goes to the recirc line on the evap system.
More Turbo
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I thought i'd let you know what i just ran across on my 78 with an electric fuel pump that the original owner said he or had installed. The mechanical pump was leaking a little oil so i bought a plate to cover the hole after removing the m/pump. after doing that i noticed that the rubber fuel line next to the original steel line from the e/pump was run threw the m/pump.why i dont know.after rerouting and reconnecting the steel line i went to check where the e/pump was getting power and found that it wasnt enen hooked up.when i powered the e/pump i couldnt believe how loud it was.so i figured it would be easier to put a m/pump back on replace the steel line with s/s incase its rusted on the inside. this way i wont have to install a return line which would be a problem with two tanks because you would be transfuring fuel from one to the other. hope this was helpful.
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