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369

R34 Gtt Neo – Fuel Pump Direct Feed Rewire

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R34 GTT NEO – FUEL PUMP DIRECT FEED REWIRE

Stock fuel pump wiring on an R34 GTT will supply the fuel pump with around 11v. This is not ideal when you are running an aftermarket fuel pump rated at 250L/hour + which requires around 13.5v or even up to 14.5v of power to run at its optimal efficiency. You can use this setup even if you just want to make your current pump more efficient and add a couple of ponies at a low cost. The following guide relates to an intake fuel pump NOT EXTERNAL.

DISCLAIMER

Attempt this at your own risk. The following tutorial is as clear a guide as I could piece together on how to rewire your fuel pump to run at 14v using information gathered from the SAU forums and from hands on experience on my own R34 GTT NEO. I am neither an auto electrician nor a mechanic. I take no responsibility for any damage that you do to your vehicle in the process of following this guide. Consult your tuner or auto electrician or mechanic before you undertake this procedure to make sure it suitable for your R34 GTT NEO.

PARTS

These parts can be purchased from Jaycar, supercheap auto or autobarn.

  • 8GA OFC Red Power Cable x 6m
  • 8GA OFC Black Power Cable x 6m
  • Fuse Holder x 1
  • 30AMP Fuse x 2
  • 30AMP Horn Relay x 1
  • Red/Black Large Eye Terminals for 8GA x 2 packs
  • Yellow 5.3mm Insulated Eye Terminal x 1 pack
  • Yellow (male) 6.4mm Insulated Spades x 1 pack
  • Blue (female) 6.4mm Insulated Spades x 1 pack

TOOLS

  • Crimping/cutting tool
  • Socket wrenches
  • Pliers
  • Screwdrivers
  • Cable ties
  • Electrical tape
  • Multimeter

COST

  • If you already have the tools then the parts cost approximately $55 from JAYCAR.
  • With tools it's somewhere around $110.

DIRECTIONS

  1. Disconnect negative terminal on the battery so that sh*t don't blow up!
  2. Locate the fuel cell lid in the boot underneath the boot lining. You will see 4 to 6 wires leading into the lid from the ECU. The black/yellow wire is positive and the green/white is negative. The other wires are for sensors.
  3. You will see cables taped up leading towards and into the fuel cell lid. Start un-wrapping the tape approximately 100mm from the fuel cell lid until approximately 150mm of cable is visible. This allows enough cable to be cut and joined.
  4. Cut the black/yellow (POSTIVE) wire into two.
  5. Connect the side of the black/yellow wire that comes from the ECU to PIN85 of the Relay using a female spade connector.
  6. Connect the other side of the black/yellow wire that leads to the fuel pump to PIN87 of the Relay with another female spade connector.
  7. Connect the 8GA red cable to the POSITIVE terminal on the Battery with the Large Eye Connector.
  8. Connect the 8GA red cable to the 30A fuse (in fuse holder) using male/female spade connectors on either end of the fuse holder.
  9. Connect the 30A fuse to PIN30 on the Relay using male/ female spade connectors.
  10. Cut the green/white (NEGATIVE) wire into two.
  11. The green/white wire from the ECU is cut and capped/taped.
  12. Cut the green/white wire once again into two.
  13. Connect the 8GA black cable to the end of the green/white wire that is still connected to the negative terminal on the fuel pump using the male/female spade connectors.
  14. Connect one end of the green/white wire leftover to PIN86 on the Relay using a female connector and the other to the Chassis bolt for Earth using a yellow eye connector.
  15. Connect the other end of the 8GA black cable to the NEGATIVE terminal on the Battery (or Chassis bolt for Earth) with the Large Eye Connector.
  16. Double check all connections and ensure all it properly connected. Wrap any loose wires together using electrical tape and/or cable ties.
  17. Use the multimeter to test voltage.
  18. Start her up with fingers crossed!

NOTES

  • Run the 8GA red and black cable along the fuel line and ties together with cable ties.
  • Alternatively you could feed the 8GA red and black cable into the back seat somehow and under the carpet along the driver's side of the car.
  • If your battery has been relocated to the boot of your R34 then a meter or so of 8GA red and black cable is better.

R34 GTT fuel pump wiring

NEGATIVE Green/white needs to go from fuel pump to chassis earth.

NEGATIVE Green/white from ECU to pin 86

POSITIVE Black/yellow from ECU loom to pin 85

POSITIVE Black/yellow from fuel pump wiring to pin 87

POSITIVE battery 12volt supply to pin 30 with a 30amp fuse at the battery end of this wire

ACKNOWLEGMENTS

Cubes – SAU member

http://www.skylinesa...ct-feed-rewire/

R 2 THE J – SAU member

http://www.skylinesa...your-fuel-pump/

Gumflapper – SAU member (wiring diagram) http://www.skylinesa...ttach_id=289665

Thanks to SAU members who provided their hands on experience and technical input on various threads.

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I did this , but people it seems some people swear by it ground for has to be connected to the negative terminal on the battery. Personally I think a good ground is all it takes and the most direct route is best. My Japanese friend swears by everything direct from the battery terminals. Has one way been confirmed bettwe than the next?

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I have a white wire with a green stripe and a black with yellow stripe, their is 13.6v at idle on the black wire and the white one has 5.6v which increases as you rev the car is that right or shouldn't the white have anything? Thanks

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Did this to my 34, very easy to follow and materials were around $65 from Jaycar in Adelaide, I did 2 mistakes which I will describe below and this might help anyone doing this mod, Also I fitted a Walbro intank pump whihch required the existing filter sock to be used:

Firstly I cut the original wiring between the Fuel tank Lid and original pump wiring. I had a brain fart and realised after cutting that the Nissan loom plugs straight into the Walbro, I like to try and eliminate connectors/joins but when I saw the spade connectors on the Walbro harness I thought I had to cut and join that to the Nissan loom. I also opted to use the red type crimp joiner rather than the spade connectors supplied in the Walbro loom.

Secondly I mounted the relay to one of the screws that holds the fuel lid cover on, reason been was because I cut the loom a little bit too short and didn't have the room to stretch it any more but I would have prefered to mount this else where as the boot carpet linings sit ontop of the wiring and relay. I might opt to move this or somehow cover the relay and wiring. I'm abit padantic and even though the car has wiring all over the loom having a relay hard wired to 12V covered by insulation and carpet isn't something I like to do.

Once again great write up

Edited by rb2534
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thanks for the mod. guys if i will buy GTR (r33 or r34) fuel pump will i need to do this mod?

and what problems may occur if i will install univeral Tomei (made by walbro) fuel pump without doing this mod (FPR + boost 0.8 bar = 11psi)?

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Hey 427

Are you planning on buying a brand new 33 or 34 GTR Pump? Reason I ask is I went down the same path and realized that they are at least 10 years old. I bought a brand new Walbro from Kudos for about $120. Brand new in the box ready to go.

Just some food for thought

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Hey 427

Are you planning on buying a brand new 33 or 34 GTR Pump? Reason I ask is I went down the same path and realized that they are at least 10 years old. I bought a brand new Walbro from Kudos for about $120. Brand new in the box ready to go.

Just some food for thought

yeah i know the prices for pumps. used 34 GTR is about 50-100 usd from yahoo. i bought used Tomei (which is walbro made) for 40 usd from yahoo, but it needs to be rewired, actually i don't want to make any mods to my wires in car, better get a user R34 GTR pump and fit in withou any wire mode.

but the questions are still opened:

if i will buy GTR (r34) fuel pump will i need to do wire mod?

and what problems may occur if i will install univeral Tomei (made by walbro) fuel pump without doing this mod (FPR + boost 0.8 bar = 11psi)?

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^^ good question and great tutorial, but I would also like to know this.

If replacing the standard gtt fuel pump with a gtr one, would one still have to rewire it or will it be fine to 'swap n go'? And same with the tomie / bosche pumps any detremental effects from not doing this mod?

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Did this to mine the other day, so easy to follow cheer's!

I used a relay i had in the shed with a nice plug on it and loom, finished the job and hooked the battery back up and fuel pump started, was like WTF, triple checked wiring, all good. Ended up being the relay was a change over realy! Took me a while to figure that one out lol.

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I did this rewire on my GTT, worked okay the fuel pump much louder, weird was it was only sometimes louder like it switches on more at times.

Problem is now it sounds like a powerstation, makes the loudest buzzing noise! What could that be ? It works fine still pumps fuel at boost.

Thanks

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I'm finding it weird that the negative wire from the ECU is taped off.

I followed this tutorial, but when i try to start her up, it won't start up. It just tries to?

Does the negative wire from the ECU really get taped off, or am i supposed to ground that wire to the chasis?

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Have you earthed the relay?

You should have the two smaller posts Yeh? One of which is connected to the black/yellow positive wire? The other one needs to be earthed. So you cut and tape the green/white (or black/red in some cases) wire from the ecu, and earth pin 86 of the relay.

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what do you mean 2 smaller posts?

ok so i've done this:

1. pos wire from ecu to relay terminal 85

2. pos wire from pump to terminal 87

3. neg wire from pump to battery

4. neg wire from ecu to nothing (taped off)

5. wire from pin 86 to bolt on chasis for ground.

no start, just struggles.

i also tried connecting neg wire from ECU to pin 86 and nothing as well, just car struggling.

the pos black/yellow wire joins into 1 from 3 separate ones, so i just cut the joined single one (if that makes sense)

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Well there's the issue. Where's your positive wire from the battery to pin 30?

Relays have two circuits, a low current circuit and a high current circuit. The low current circuit is your ecu wires, they give power to the relay coil which completes the high current circuit. You've done this part correctly. But you don't have a high current circuit. You need to wire a 8ga cable with an inline fuse from the positive terminal of the battery to pin 30 of the relay. This is where your fuel pump will get its power from.

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oh i forgot to mention that too. i have power through 8g cable to inline fuse (30A), and that's connected to relay terminal 30.

So in saying that, i have no idea why it isn't starting up if you say that's the only issue?

:(

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