32 Gtr Fuel Pump Rewire

[33SOM]

Hi all,

Rewiring my fuel pump with a relay to suit a Walbro 460l but have ran into some problems..

It's wired as follows

On the relay terminal 30 goes to the battery via 8g wire

Terminal 85 goes to the chassis

Terminal 86 is from the old fuel pump wire (the side going to the fuel pump controller)((the trigger wire))

Terminal 87 is going to the fuel pumps positive wire.

The pump is earthed directly to the chassis.

Problem is the car turns over but won't fire. I can hear the fuel pump priming. It only runs when using the original positive wire on the pump

I have tried using different relays

Disconnecting the fuel pump controller

I even ran a wire directly from the battery to the fuel pumps positive just to see if it would start... And it wouldn't

The previous owner had wired the pumps earth directly to the body

Any help appreciated!!

[Hadouken]

edit**

Seems yours is wired the same.

Are you sure it is the fuel pump priming and not the attesa pump you are hearing?

It doesnt make sense that it will work with the original wire and then not through the relay.

Have you checked the terminals on the relay after you have switched the ignition to reds? By that I mean go to pin 86 make sure you have your pump signal then go to 87 and check to see if power has come through.

this is very weird.

maybe post some pictures

[33SOM]

That's how its wired with the exception of the "red wire" being yellow/black in the 32r

I have tried a narva and a bosch relay with no luck.

Bypassing the relays it still wouldn't start..

[Hadouken]

I edited my post sorry

[Hadouken]

Is this with the standard ecu?

[33SOM]

Cheers for the reply,

Yeah pin 86 gets power for a couple seconds after flicking the ignition on.

Pin 87 has power for a couple seconds also after turning on the ignition, I can heaR the pump and have checked with a multimeter that it's getting 12v through the relay

Something else is stopping it from firing...

Ecu is Nistune.

[Blackkers]

Something that needs to be double checked:

The polarity on the pump. Don't be embarrased if you get it wrong. From memory the black wire is positive on the fuel pump or something weird.

If the polarity is reversed it will sound like it's running but really it's going backwards and the car won't fire

[Hadouken]

What a good point!

make sure you let us know how you go

[jiffo]

Are you sure you have the correct voltage on the wire going to 86 of the relay?

I wonder if you have the reduced voltage signal (the output of the FPCM) which would have difficulty holding in the relay when the engine is cranking.

[33SOM]

The earth is attached to the chassis whether the pump is powered via relay or the original wire so polarity must be correct.

I did think the voltage going to terminal 86 might of been too low to turn the relay on (pump is getting 9.4v when the car is idling) hence why I tried with the pump connected straight to the battery.

Cheers for the replies!

Edit: I have a feeling the wiring has been messed with further up the harness

Edited June 5, 2015 by 33SOM

[Hadouken]

Good luck.

[jiffo]

I don't like having a relay operating the FPCM operating another relay, simple is best.

So I'd use the ecu Pin 18 as my trigger. (Pin 18 goes to ground to activate the pump)

My relay would have:

Relay 85 to Pin 18 of the ecu.

Relay 87 to positive feed for the fuel pump.

12V+ in to Relay 30 and looped to Relay 86.

[33SOM]

I like the sound of that.

Does pin 18 on the ecu end up at the fpcm? Or should I just run a wire straight from the ecu?

[33SOM]

Plug at the fpcm..

Edited June 5, 2015 by 33SOM

[iruvyouskyrine]

That's how its wired with the exception of the "red wire" being yellow/black in the 32r

I have tried a narva and a bosch relay with no luck.

Bypassing the relays it still wouldn't start..

The 'red wire' is not the yellow/black one that is earth. The power wire is white/purple. This is the case in 32 gts-t anyway I imagine it would be the same in GTR.

[Blackkers]

The 'red wire' is not the yellow/black one that is earth. The power wire is white/purple. This is the case in 32 gts-t anyway I imagine it would be the same in GTR.

I think it's different. From memory there was a brown/white and black wires

[jiffo]

My experience with re-wiring has been with re-powers where there's no problem cutting into a harness, and I haven't touched my GTR so if my info isn't right feel free to correct.

To me Mr Nissan has already done the job for you.

For the positive feed, you just have to install larger cable to the fuel pump relay and of course larger cable from relay to the pump.

On the negative side of the circuit, the FPCM etc can all stay where it is, simply supply the pump with a larger cable chassis ground.

I believe the fuel pump relay for a 32 GTR is behind the centre boot trim. You should find 2-relays, one is fuel pump the other is ATTESSA.

[33SOM]

Cheers for the replies.

I have tried with the fpcm hooked up and disconnected.

I also tried using the trigger wire before the factory fuel pump relay to trigger my relay

I tried switching polarities. The pump just blew a fuse.

As stated earlier the pump directly to the battery running at full noise still won't get the car started.

Positive wire on a 32gtr is 100% black/yellow. I pulled the pump out to confirm..

[Blackkers]

Maybe check other fuses?

[33SOM]

But it fires when the original wire is on the pump.