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(QUICK ?) Fuel Pump rewire (searched)

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Old Dec 22, 2003 | 09:12 PM
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(QUICK ?) Fuel Pump rewire (searched)

in the write up on 1300CC.. the text part is hard to understand (the way its written).. the pen drawn is easier.. except i have one question. is the relay and the "aluminum box/heat sink" connected together? its raining outside and i have no garage so i cant look. and if they are connected.. is it telling you to cut it where the red mark i put is?....
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Old Dec 22, 2003 | 09:14 PM
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i know it looks like they are connected in the pic.. but im just being ****.
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Old Dec 22, 2003 | 10:09 PM
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No.. you want to leave everything on the relay/resistor unit intact, so that you can keep it working in the back of the car. They're run in parallel .. the resistor (aluminum box) is used by the ECU to lower fuel pressure (by dropping the fuel pump voltage to ~9 volts) when the ECU 'senses' a need for more fuel, it turns on the relay, bypassing the resistor (not completely, but now the relay is a lower resistance path, so current flows across it).

The common rewire proceedure has you moving that whole unit to the back of the car next to the fuel pump. That way you keep the ECU's capability to lower fuel pressure.
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Old Dec 22, 2003 | 10:23 PM
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you move the heatsink looking thing also? so where do you cut the wires??
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Old Dec 22, 2003 | 10:39 PM
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i cut the wires on the ecu side of the plug. this way i can bring both parts of the white connector to the rear. so that i can test/replace the resistor relay when necessary. i cut the six wires about 3 inches away from the plug to give me enough wire to work with at the rear.

1 2 3
4 5 6

on the ecu wires, use a butt connector or solder and hook the #1 and #4 wires together. then connect the #3 and #6 wires together. using speaker wire of at least 18GA, run the #2 and #5 wires to the rear along with a 12GA power wire from the battery. don't forget to fuse the power wire as close to the battery as possible. i'm assuming you have a diagram on the rest of the precedure.
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Old Dec 22, 2003 | 10:43 PM
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yes i have 2 diagrams and the writeup... i would be lost without the diagrams.. that writeup is so confusing (just the text). thanks for the confirmation.. one last thing, does the ecu side plug into the resistor or the relay? (car, rain, yeah)
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Old Dec 22, 2003 | 11:07 PM
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The relay / heatsink is actually the resistor pack + relay to activate it. There is no point in having the relay without the resistor pack as well. Thus you keep the entire unit functioning as one. What I'd do is cut the plastic back around the pins, use heatshrink or tape and solder each connecting wire to the appropriate pins, insulating where necessary. To this you need to ADD another relay (the 30A) unit to switch the ENTIRE fuel pump on and off with the normal signal from the ecu. That is the bare relay shown in the wiring diagram. Got it?
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Old Dec 22, 2003 | 11:20 PM
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yes but does the plug with the wires leading to the ECU connect to the resistor or the relay??
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Old Dec 22, 2003 | 11:28 PM
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Old Dec 22, 2003 | 11:43 PM
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Thanks for the image NZ, I also have tried to read through that rewire writeup only to be confused beyond belief 1/2 way though.

I will be able to do it now!
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Old Dec 23, 2003 | 01:37 PM
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still no one said what the plug u cut is connected to. the resistor or the relay.. doo dee doo
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Old Dec 23, 2003 | 04:06 PM
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Originally posted by imloggedin
still no one said what the plug u cut is connected to. the resistor or the relay.. doo dee doo
it's one plug for both... 6 wires.
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Old Dec 23, 2003 | 04:07 PM
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Okay. In general, you don't cut the plug per se. You take the wires BEHIND the plug on the HARNESS side (e.g. from the engine harness, leaving the plug (both sides) resistor pack AND relay unit all wired as you show in the pic, then mark each wire A, B, etc.. so you don't lose track of which one is which once you cut the plug off the harness, then cut them ALL, as you will end up using all SIX (6) wires in that entire set, e.g. both the relay AND the resistor (see all our posts before regarding how you need them BOTH). Does that make sense?

------- |------|=|--- >
------- |------|P|--- >
------- |------|L|--- > To resistor + relay pack
------- |------|U|--- >
------- |------|G|--- >
------- |------|=|--- >
^ CUT HERE
^ Label HERE according to pins in plug

Got it?
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Old Dec 23, 2003 | 05:36 PM
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i know where to cut it.. i understand why you cut the plug toward the ecu side.. i know this.. alls i wanted to know was where the plug connects.. to the resistor or to the relay.. and i think scott answered my question in saying that it connects to both. one set comes from resistor one set comes from relay and both run into the plug?
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Old Dec 23, 2003 | 06:50 PM
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Yes that is correct. The two big black wires leading to the box with fins are the resistor leads. The other wires are the relay leads (from the other box on the bracket). The ECU simply chooses, via the relay, whether the resistor is switched into the fuel pump circuit or not.

sorry 'bout that. Thought you were still confused about the location of the cut and the mechanics thereof.
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Old Dec 23, 2003 | 07:32 PM
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nope i just had lack of light and dryness to go check in my car lol thanks though.
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Old Dec 23, 2003 | 07:37 PM
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is 18 gauge speaker wire good enough?
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