HOWTO: Fuel Pump Rewire

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dawm
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HOWTO: Fuel Pump Rewire

Post by dawm » Mon Oct 01, 2007 9:16 pm

Seems to be alot of commotion on srtforums about the fuel pump rewire mod, couldnt find any pictures of the original instructions but theres a couple venders charging $90 for a plug in play kit (still gotta cut 1 wire). so i figured id draw up the instructions.

apparently the SRT computer drops the voltage to the fuel pump from 12v to 8v around 4800rpm. running the pump under voltage isnt good on the components inside which shortens the life of the pump and it also slows down the flow. so supplying a 12v feed (from the alternator) all the time (triggered thru a relay via the stock feed wire) gives the pump the power it requires all the time. they claim this will improve AFRs and MPG.

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04 Dodge Neon 2.4L - Going full SRT swap (project)
12 Subaru WRX Hatchback - Stage 1 (daily driver)
98 Neon R/T Coupe 2.4L - Going NA w/ ITBs (project)
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Post by -db » Mon Oct 01, 2007 9:50 pm

Why run a new wire all the way back there? Are they saying there is a large enough current drop on the line to warrant running the 10ga? If just making a constant 12v on the line will make the difference, then why not just install the relay up by the pcm? You would still only just cut the one wire, but you would want to use a weather pack relay socket.

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Post by dawm » Mon Oct 01, 2007 10:02 pm

-db wrote:Why run a new wire all the way back there? Are they saying there is a large enough current drop on the line to warrant running the 10ga? If just making a constant 12v on the line will make the difference, then why not just install the relay up by the pcm? You would still only just cut the one wire, but you would want to use a weather pack relay socket.


not sure why they are using 10 gauge

i just made a diagram of the mod after seeing some vendors starting to sell it and the lack of instructions in the original howto thread on srtforums.

http://www.srtforums.com/forums/showthread.php?t=389383
04 Dodge Neon 2.4L - Going full SRT swap (project)
12 Subaru WRX Hatchback - Stage 1 (daily driver)
98 Neon R/T Coupe 2.4L - Going NA w/ ITBs (project)
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02 Neon R/T - 08/08/08 traded for the Caliber (which was traded for the STI 03/14/11)

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Post by ZippyR/T » Tue Oct 02, 2007 1:17 am

but why does the srt pcm drop the voltage... hard to believe its an accident unless its running something else thats stealing power. why would chrysler do stuff to hurt the car
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Post by -db » Tue Oct 02, 2007 8:04 am

Most all of the answers are posted in the SRTforums thread. Basicly people are saying the voltage drop is due to haveing a to small of gauge wire back there. They also stated that the wire has 4 seperate connection points. This causes a couple volt drop at idle and once driving the wire heats up and causes an additional voltage drop. The 10ga wire is well more than suffiecent, maybe overkill for running back there. I have not done any testing, I just read the post over there.

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Post by 2KNightRiderES » Tue Oct 23, 2007 4:53 pm

Crap... and I just re-installed my tank w/255 and half a tank of gas. :-/
jonnymopar wrote:If it's got 4 wheels and you enjoy it, it's a money pit :D

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:lol:

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Post by dawm » Tue Oct 23, 2007 5:19 pm

2KNightRiderES wrote:Crap... and I just re-installed my tank w/255 and half a tank of gas. :-/


you only mod the connector, shouldnt have to do anything but unplug and rework
04 Dodge Neon 2.4L - Going full SRT swap (project)
12 Subaru WRX Hatchback - Stage 1 (daily driver)
98 Neon R/T Coupe 2.4L - Going NA w/ ITBs (project)
Image
02 Neon R/T - 08/08/08 traded for the Caliber (which was traded for the STI 03/14/11)

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