fuel pump power?
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fuel pump power?
hey im converting my 87 efi 302 in my f-150 to carb .....my question is ......i was told in a previous post that my fuel pump is powered through my computer....can i just run 12v straight to the wire that leads to my pumps, or should i buy an aftermarket fuel pump...(dual tanks, with low pressure in tank pumps .....and going to remove frame mounted high pressure pump) thanks
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From: Louisville,Ky.
You can just wire a power trigger wire to the green fuel pump relay trigger and attatch the ground to the chassis. Run your trigger wire from a power source that is only hot with the key on.
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thanks lxman.....by relay trigger...im assuming you mean the outgoing wire on the relay that heads to the inertia switch next...i think according to my haynes schematic there is 12v ignition power going in to the relay, but it looks like the eec iv somehow switches it....looks like i could just bypass the eec connection.....thanks much
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From: Louisville,Ky.
Yes, the two smaller wires trigger the relay to close and power the pumps. The reason that I said to ground one side is because the ECM actually supplies a ground to energize the relay coil. You will switch the positive relay coil wire and connect the ground to the chassis.
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From: Louisville,Ky.
Or you can get a set of pumps for an 85 F250 with a 460 4bbl with the hot fuel option. You will probably need like a Mallory or Holley regulator. The low pressure pumps in the tanks are probably about 12psi and you don't want any more than 6.5psi with a carb.
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ok...i was told in my engine swap post that the low pressure intank pumps make about 6psi, which is why i was going to just use my whole setup, and remove the frame mounted pump.....i wonder if i just installed a pressure regulator if it would burn the pumps up? if theyre putting out 12 psi that is?
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Hotshot
Joined: Oct 2002
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From: The Big, Oregon
I would recommend a regulator, it will actually improve the life of the pumps since fuel would be able to flow constantly. Use an adjustable Edelbrock or Holley regulator, set it for 7-ish, and you'll be good to go.
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I thought even the throtle body pump make about 16psi but am not sure on that one. If it only makes 6 you should be fine. A bypass regulator would send the extra fuel back to the tank which help the pump run free and the gas stay cooler.