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Old Sep 21, 2012 | 01:28 PM
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Ok, well, got a mp-4303 fuel pump, and i wont be using my old pump whatsoever. Is it possible to just splice into the old fuel pump wiring harness that plugs into the sending unit to power my fuel pump? Any help will be appreciated. yes, i searched, but nothing specific came up for my current question.

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Old Sep 21, 2012 | 01:51 PM
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That's a big pump that should run a heavy gauge power and ground wire with a relay. I would not splice into the stock wiring for that.
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Old Sep 21, 2012 | 01:55 PM
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ya, sort of figured that. ohh well, guess ill just order the racetronix PNP hotwire kit. Thanks for the info DopeFedZ
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Old Sep 21, 2012 | 01:57 PM
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Next question, i see on the racetronix PNP hotwire kit, that it uitilizes the factory pump power harness. Could i just splice into that for power to my 4303 since i wont be utilizing my old fuel system whatsoever?

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Old Sep 21, 2012 | 11:30 PM
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I'd do a separate harness with power direct from the battery and use the factory wiring to trigger the relay.
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Old Sep 22, 2012 | 02:12 AM
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Originally Posted by Blown06
I'd do a separate harness with power direct from the battery and use the factory wiring to trigger the relay.
are there any diagrams/write-ups on how to do this?
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Old Sep 22, 2012 | 10:52 PM
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It's pretty easy. I've run mine that way in the past and it works just like a factory pump.

Run a heavy gauge power wire direct from the battery (or even back of the alt.) to the input side of a 40amp relay.

Run a heavy gauge power wire out of the relay directly to the pump

Ground the relay

Ground the pump

Use the factory fuel pump power wire to trigger the relay.
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Old Sep 22, 2012 | 10:53 PM
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Might be a good idea to put a fuse before the relay. 30 amp should protect you.
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Old Sep 22, 2012 | 11:53 PM
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Originally Posted by Blown06
It's pretty easy. I've run mine that way in the past and it works just like a factory pump.

Run a heavy gauge power wire direct from the battery (or even back of the alt.) to the input side of a 40amp relay.

Run a heavy gauge power wire out of the relay directly to the pump

Ground the relay

Ground the pump

Use the factory fuel pump power wire to trigger the relay.
Thanks a TON Blown06, it makes perfect sense, and actually sounds as easy as you say haha. Which is the factory fuel pump wire? there are several wires on the harness that plugs into the old sending unit.
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Old Sep 23, 2012 | 12:09 AM
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disregard, found an exact diagram showing what you said. shows the red wire for fuel pump power. Thanks again
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Old Sep 23, 2012 | 12:18 AM
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another quick question, might be dumb, but would a 10ga or 12ga be to big?
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Old Sep 23, 2012 | 02:59 PM
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I would do 10.
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Old Sep 23, 2012 | 03:03 PM
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Originally Posted by DopeFedZ
I would do 10.
Thanks alot for the help! got it all figured out on fueling now, and 10ga it is!
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Old Sep 24, 2012 | 12:00 AM
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Good decision on the 10
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Old Sep 24, 2012 | 05:12 AM
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ordered a 10ga fuse holder with 30amp, and my 30amp relay. Now just got to get some 10ga wire and im all set on my fuel system wiring. Once again, Thanks Blown06 and DopeFedZ
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Old Sep 24, 2012 | 06:14 AM
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Originally Posted by nick.celis
disregard, found an exact diagram showing what you said. shows the red wire for fuel pump power. Thanks again
Can you post the diagram. Might help someone in the future.
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Old Sep 24, 2012 | 08:06 AM
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Originally Posted by Ollie8974
Can you post the diagram. Might help someone in the future.
Not a problem, hope it helps someone else in the future! I actually found it off Ls1tech, so all credit goes to original poster!

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Old Sep 24, 2012 | 11:37 AM
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Good stuff. I use the racetronix pump setup and their harness for my main pump and turn on the other intank when I turn on either nitrous kit. Simple enough to do. Good luck!
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Old Sep 24, 2012 | 12:13 PM
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im only running one big pump didnt want to have to rely on a hobbs switch, and its not my DD so im not to concerned with the heat/vapor lock, not to mention im running a -10 feed and -8 return
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