problem with defi rpm gauge

[Project D]

The dizzy signal (toothed wheel + vr sensor) don't go straight to the ECU, it go to the igniter (small box over the coil) and the igniter convert this signal to the Ne Signal for the ECU...
But maybe you're right about the frequency (too high ?)

Instead, the IGT signat goes from the ECU to the igniter,
it "drive" the coil so the signal must be good
(2 spark / rev, like any 4 cylinders engine)

here is how it work: