which wire goes to the tacho

[Sam]

Hi Folks

On Alfettas, does the tach signal come of the coil's negative terminal, or does it get the signal some other way?

I can't imagine any other way, but ......

currently, the coil's negative terminal has 2 white wires coming from it.
One of them is wrapped up in insulation tape with other wires and It seems to go through the firewall.

When I open up the back of the instrument cluster, there are so many wires and crap in there, it's hard to tell whats going on. I looked pretty hard but couldn't see any white wire going to the instrument cluster (and hence the tacho).

I'm installing an EDIS 4 ignition module that I want my megasquirt to control.
I'm slowly working though the install and I have come to the point of getting my Tacho working with the EDIS 4, but dont know which wire to connect it to .

Thanks in advance
Sam

[Sam]

choderboy - thanks for your help,  much appreciated

Sam