Tacho not working with coil over plugs setup

[ATAl]

I'm running coil over plug ignition in my ae92 levin gtz and the tacho isn't working.

Using 1zz-fe coilpacks.

Currently I'm just taking the IGF signal off each coilpack then all four wires are joint together and connected to the tacho wire. I'm assuming this will create a 5v square pattern (might be 12v haven't measured it yet).

Can anyone tell me what the gtz tacho is expecting to see? Voltage spikes or square wave, and how many volts?

Or have I done something fundamentally wrong here?

Cheers.

[ChaosAD]

http://www.autoshop101.com/forms/h39.pdf

[ATAl]

Ok, so basically I'm going about this the wrong way and the IGF signal is no use as a tacho drive?

[matt dunn]

what ECU are you using to run 4 coils?

[sergei]

Ok, so basically I'm going about this the wrong way and the IGF signal is no use as a tacho drive?

IGF is not a tacho signal, it is feedback signal to ECU so it knows coil has fired. It is not a square wave.

[MAGN1T]

So what would you do then?

Steve

[sergei]

So what would you do then?

Steve

obviously he is running some aftermarket ECU to drive coils, so get that to drive tacho.

[ATAl]

Yip, running a link g4 so am going to use an aux out as the tacho signal.