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Join Date: Sep 2006
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2005 mustang Fuel pump wiring upgrade -
Do this at your own risk, I accept no responsibility for damage to you or your vehicle.
If you have any doubts, do not attempt this modification.
How to upgrade the wiring to your FPDM (fuel pump driver module) on a 2005 Mustang
This is to supply the FPDM with a less restrictive electrical supply, which can reduce the duty cycle of your fuel injectors when using 39lb injectors and a stock fuel pump. This could reduce the chance of the vehicles AFR leaning out at higher rpm’s. See VMPtuning ‘s how-to forums for dyno results of this mod on a 2005 V6.
Disconnect your battery first
Please read this and look at the pictures before beginning!
You will be running a 10 gauge wire from your engine compartment fuse box to the FPDM located in your trunk next to the spare tire, installing a 4 pin automotive relay, cutting the white wire in the FPDM wiring harness and installing a ground wire. You begin by taking everything out of the trunk and removing the passenger front tire and inner fender well.
You will need-
18’ of 10 gauge red wire, 12” of 8 gauge black wire, a 4 pin automotive relay, a 30 amp fuse and holder (the fuses do not come with the holder) spade connectors, electrical tape and wire ties.
1. Empty the trunk, the FPDM is located in the spare tire well on the left rear
2. Remove the front passenger inner fender liner.
3. Run your 10 gauge red wire from the trunk to the engine compartment. Route the wire along the passenger side of the car, under the rear seat interior panel (you do not need to take the panel off) Take the passenger side door sill off and run the wire under the carpet. Remove the passenger side front kick panel and run the wire through to the grommet that your antenna wire runs through. Cut a small slit and run your red wire through .
4. From the fender well route your wire through the slot into the engine compartment, the wire will come out under your battery. Route the wire to the fuse box.
5. Attach your fuse link to the red wire and to the fuse box. Do not inset the fuse yet.
6. In the trunk, disconnect the FPDM plug from the FPDM, then remove the electrical tape covering the wiring harness to the FPDM. Cut the white wire a few inches from the connector. If you cut the white wire in the right spot you will not have to lengthen it. Attach a spade connector to each end of the white wire you cut. Attach a spade connector to the red wire. Attach a spade connector to a 6” long piece of black wire, you will use this for your ground. Connect the wire coming from the harness to pin number 86 on the relay. Connect the white wire coming from the plug to pin number 87 on the relay. Connect the black wire to pin number 85 on the relay. Connect the red wire to pin number 30 on the relay. Attach the ground to the vehicle. I drilled one hole to mount the relay and attach the ground to.
Relay fully attached and installed
Now reconnect your battery , look over everything, then insert your fuse and start the car. Then re-attach the doorsill, kick panel, etc.
BECAUSE--- if this does not work for some reason, like you got a bad relay, or did not know that the fuse link did not come with a fuse and you don’t have any but you wired the car up and need to get to the store to buy fuses----You can make a jumper wire to connect the white wire back together again, which will get you to the store where you can disconnect the jumper, attach the white wires to the correct pins on the relay, install the fuse and drive home. Keep the jumper in the car, you might need it for something some day.
2005 V6 Automatic. Vortech V2, Chargecooled, 15 PSI. 4:10's in the 7.5.
12psi and 75 shot