If I have the black and purple wire connected to the coil (same side as the condensor) the car wont start. As soon as I unplug it the car starts right up. I figured that maybe there was a short in the wire, so I made a test lamp, touched one side to the tach wire and the other to the + side battery term (I checked the bulb by touching the wire to a ground and it lite fine. I then ran a seperate new wire from the tach to the coil and still the same, no start. I checked the wiring and it is connected fine, there is power to the tach and the ground is fine. If the car is running and I connect the wire the tach works fine and the car still runs. Oh I also tried a second tach I had.

Check out this link - it may help you with your wiring. You may accidentally have an anti-theft device.... http://www.pelicanparts.com/techarticles/M...tion_cutoff.htm

I thought of that, but I ran a new wire from the tach over the rollbar and onto the coil with the same results