DIY: GTM Fuel Pump Voltage Stabilizer installation
 

I know GTM includes this with the Stage 1.5 and Stage 2 kits and if I remember correctly, GTM recommends the upgrade if you are near 450WHP. It does give a more steady supply of electrons to the fuel pump when compared to the tiny factory wires. I am at 419WHP, and I decided installing this could not hurt.

Copied from the GTM website:
We found that the 370Z and G37 encounter problems where the voltage drops significantly through the small gauge factory wires to the fuel pump. Our GTM Fuel Pump Voltage Stabilizer Kit not only replaces the puny factory wires with a heavier gauge, it provides a dedicated circuit to ensure that your fuel pump gets the voltage necessary to keep your car running optimally all the time. Remember, stable fuel pump voltage means stable fuel pressure!

Tools and items needed:

• GTM Fuel Pump Voltage Stabilizer ($69.05 plus shipping)
• Moving blanket on the work area as knee padding and a place to lay out the tools (just something I do)
• Heat gun, heat shrink, soldering iron, and solder to make secure connections on the wires
• Something to use as a fish wire to drop the wire through the firewall
• A pair of dikes/diagonal pliers/wire cutters
• Split wire flex loom and/or abrasion resistant sleeving (just something I do to give an OEM look for the wiring)
• 3M Electrical tape
• Ratchet and 10mm socket (to remove the fuel pump access door)

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Disclaimer
I take absolutely no responsibility if you decide to perform this DIY. The install deals with electricity and your fuel supply from the fuel pump, so do it at your own risk.

Step One – Windows and battery
Write down your radio presets, roll down both of the windows and remove the negative battery terminal. Also, remove some trim pieces and a piece of the cowling to reveal a large factory grommet. All of the pieces are retained with simple pop clips.

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Step Two – Mount the Relay
Find a suitable location in the passenger side kick panel and mount the relay assembly. I used a small screw and some Velcro. Remove the passenger kick plate to give access to run the wires towards the fuel pump behind the passenger seat. I took some time and wrapped my wiring in sheathing, flex loom, and/or electrical tape.

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Step Three – Gain access to the fuel pump wiring harness
Slide the passenger seat as far forward as possible and open the storage compartment door. It takes a little force, but lift up one side of the door and then remove it. You can now remove the carpeted access cover and then the sound insulation mat. You should see the fuel pump access door and wiring harness for the fuel pump. Remove the fuel pump access door with four 10mm nuts. Then unplug the connector.

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Step Four – Wiring up the fuel pump voltage stabilizer
Terminal 87 (Yellow Wire) – Run this wire through a grommet on the firewall and connect to the positive battery terminal. DO NOT put the fuse in the fuse holder just yet.

Terminal 86 (Grey Wire) – Connect this wire to a suitable ground location. I grounded in the kick panel where I mounted the relay.

Now, separate the flex loom for the fuel pump access door on the OEM wiring harness, isolate the pink wire and cut it.

Terminal 30 (Red Wire) – Solder and heat shrink this wire to the pink wire on the fuel pump wiring harness on the connector side, meaning towards the fuel pump itself. Note: I ran this wire in some abrasion resistant sleeving inside some flex loom for an OEM look down the passenger side of the car.

Terminal 85 (Orange Wire) – Solder and heat shrink this wire to the other end of the pink wire on the fuel pump wiring harness.

This is not my picture but shows the reference for the red and orange wires. Note that the orange wire looks a little yellow in the photo.

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Use some electrical tape to conceal your work on the OEM wiring harness and then reinstall the fuel pump plug, bolt down the access door, reinstall the carpeted cover, reinstall the storage compartment door, and reinstall the passenger kick panels.

Plug in the fuse to the fuse holder at the battery and reconnect the negative battery terminal.

You will have to do the window reset so they go up and down correctly and reprogram your radio presets and maintenance minders if they are set.

Hope this helps someone out for this install.

Don't need to do this, but awesome DIY!

im guessing running a wire from battery to toggle switch to fuel pump would be too much power for the fuel pump?

isnt the current still being suffocated at the thinner wire anyway? therefore heating that wire?

As long as the voltage is right, the pump (or any other electrical device) will only pull as much power as it needs. You can run welding lead to the pump, if you want to, with no ill effects. The larger wire would mean less voltage drop but it would be a PITA to run.

I'm confused about this, myself. The intro mentions using bigger wire but it is not shown being run. Just installing a relay, without running larger wire, will have little or no effect.

I did that as I am boosted and using a walbro 485lph pump the factory cable did not had enough power and my fuel pressure drops at 7000 rpm on the dyno after couple runs, its good idea for boost people to do.