Problem with a tachometer on a Skyline R33 with an RB25DET Neo engine

[kike_kike]

Hello

First, I apologize if this is not the correct forum. Let me know and I will move it to the correct one.

I'm having a problem with the tachometer on my Skyline R33 with an RB25DET Neo engine.

I'll tell you from the beginning.

I'll tell you from the beginning.
I have the RB25DET Neo engine installed in a Nissan Patrol GU, with a Link G4X control unit specifically for that engine, 
and I have fitted a Skyline R33 tachograph to the original GU dashboard, but it doesn't work properly.

I have the tachometer connected to the positive and negative terminals of the GU panel's wiring, and the signal cable is connected directly to the ECU output pin, but the rpm fluctuates widely.

Can anyone tell me if the output signal from an R33 ECU is the same as the output signal from an R34 ECU, or if the voltage and signal type are different?

Regards and thanks.
 

[Dose Pipe Sutututu]

it's exactly the same

sounds like you have either a faulty tacho OR issues with wiring

[MBS206]

GU dashes are also know, especially on the tach, to have issues with one of the caps and another module for the power supply, and it will cause tacho to drop, also happens on the odo/Speedo too.

It's why you never trust a GU patrols Odo, as when the Speedo drops out, the odo stops counting too...