OK, well I powered up the tacho using the black ignition switch lead as advised by pop earlier. Worked fine. Then came splicing the sensor wire into the coil. I tried using the green/ground line first but no signal. Perhaps there was a signal but not the kind the tach needed? There are was a voltage setting that I had to use when calibrating the tach and in the manual it says to set it to the "hi" setting when going off the coil, so my guess is that they are expecting the pulse to come from wire to the CDI...and that was what it required! Thanks guys for sending some comments to help this thing along!
I love how the needle changes color: