The Vehicle starts, but the starter over/under cranks when starting;

Is the system programmed for Tach Ignition? If so, Follow “Reprogram Tach Ignition” steps as shown. Check the connection to the vehicle’s tach wire and make sure the wire is not broken or shorted to ground leading to the system. Try moving the Tach wire to another source, I.E. Negative Coil or Injector.