PINTO CAR CLUB of AMERICA
Welcome to FordPinto.com, The home of the PCCA => General Help- Ask the Experts... => Topic started by: biggrgivens on January 03, 2015, 04:15:57 AM
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What wire off the ignition switch should send power to the fuel pump. Currently my pump pulses when turn signal switch is activated. What color wire from switch should the fuel pump be tapped into?
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According to my 1972 wiring diagram, the blue wire with light green hash marks will provide + voltage in the start and run ignition switch positions only.
Note this is not the typical method of powering a EFI fuel pump. Normally the power comes from a "hot at all times" fused source via a relay (controlled by the EFI computer pin #22) and then via the safety impact switch, see link below. Since you moved the battery to the back, a direct fused wire off the battery to the relay would reduce wire length and associated voltage drop.
http://ohreally.mnsi.net/wiring_86-88.jpg
By "pump pulses" I assume you mean its speed varies with the turn signal lamps going on and off. If so, maybe pick up the idle rpm some to help the alternator keep the system voltage up. Assuming this occurs during no load situations (slowing down for a turn or at a stop light), the pump varying in speed some should not cause a problem that I can envision. Note all the assumptions, I could be out in left field again.
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I tapped into the coil + wire to activate a relay to power my fuel pump, back when I had a carb'ed engine with an electric fuel pump. Now I have an EFI engine in my pinto and the computer controls the fuel pump. I forgot what I did with that, but I used the coil wire again to control a relay for something in the swap. Probably for the hot-in-run wire to the computer which would ultimately control the fuel pump and other things as well....
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you should hook the computer into the fuel pump relay, the way you have it now if you had a wreck the fuel pump would still be running and with the EFI fuel pressure at almost 45 lbs is a lot fuel on the ground if it did leak, (a weenie roast is fine as long as you not the weenie :o) but a easy fix , take the ground side off the relay and run it to pin 22, so when you first turn on the car the pump will run for 2 or 3 seconds to prime up the fuel system and cut off , will start again when the engine starts , leave the wire from the coil + there , the computer grounds the other side to make it work,
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However i have it wired, i know that the computer controls the pump. It will turn the pump off if the engine isnt running after a few seconds....
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Did you install the inertia switch? without that it can still pump fuel in a wreck. at least it will shut off.
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I didnt. I dunno about the OP tho.