Replaced points with electronic ignition , now tach will not work. Tach is Sun Tach, probably 20 years old. Do I need to install a newer tach?

 

Green wire still hooked to the - side of the coil and not broken?

 

 

Green wire was hooked to + side of coil ever since I have owned the car & it worked great, but I will switch it & see what happens, Thanks

 

If this is a Mopar or Pertronix system:

Make sure the coil is actually hooked up correctly. Coil + should go to ignition run, that is, battery, and should have a radio suppression cap

Coil NEG should have the ignition switch wire from the ECU and the tach

If this is an MSD or other capacitive discharge you do NOT hook the tach to the coil