R32 Gtr Tacho Don't Work..

[GreeceS13]

I bought r32 gtr tacho gauge to fit it in my S13 dash cluster.

Before fit it, I tried to confirm that the tacho works ok.

It has 4 holes.

1. Ign

2 Ground

3 Ground

4 Signal

I connect from my battery the ground and ignition.

I connect also the ecu rpm signal.

It doesn't work

But if I connect rpm signal throught "gizzmo shift light tach recall" ( ecu -> gizzmo -> tacho )

it shows the ceremony (ceremony= every time the ign turn on, shows early shiftlight rpm, final shiftlight rpm).

If I connect the rpm signal to the s13 tacho it works the s13 tacho.

Also it stay at 100rpm when it is connected to the 12V.

What is the problem?

It needs any special ground to work?

Or something other?

[GreeceS13]

Anyone who can help me?