HOW TO: Getting tach to work 90-93 MS3Pro R8 coils
 

This is basic instructions on how to get your tach to work if you're running R8 coils and have a 90-93 Miata
If your Megasquirt is setup for a 90-93 then pin 4I inside the ECU case won't have a jumper. You'll need to install one here.

Next take pins 4/5 at the ignitor and connect those together preferably with solder
Then use a 1k ohm resistor in the Diagnostic box between B+ and IGN-
In MS the tach should already be set to TACH OUT. If your tach settings are correct you should have a working tach.