autometer tach and msd 6AL box install
I assume this is the wiring. First check would be to use multi-meter to verify ground connection and 12V power. You can use meter on AC volts, to see what is happening on tach wire, it should vary some with RPM.
I assume this is the wiring. First check would be to use multi-meter to verify ground connection and 12V power. You can use meter on AC volts, to see what is happening on tach wire, it should vary some with RPM.