[Bill Edgeworth]

You should check the voltage the MSD sees during cranking. An MSD box will not operate properly if it sees less than 10 volts. Also if you have an Optima battery they operate at about ½ volt lower than a conventional battery. They are good batteries but put you ½ volt closer to your box not working if you are experiencing major voltage drop during cranking. Cranking voltage drop is one of the reasons most ignitions have a direct to battery lead to bypass all voltage drops that can happen in cables and connections.