Nissan Repair: 93 hardbody wont start after tach install, nissan hardbody, turning the key

Question
i have a 1993 nissan hardbody 4cyl automatic. i installed an aftermarket tach the other day and it ran fine the next day. i went to leave to get lunch and it wouldnt start. it would crank but wouldnt kick over. i did get it started that day by turning the key on and cycling the gears and it started right up. over the next 3day it happened 3 more times. i went to leave for work today and it wouldnt start did the same thing and still wont start. is there possible an exposed wire thats causing the truck not to start? thx for all your help
P.S. i have a bad tranny that is missing 2nd and 4th gear. tranny fluid is full so thats not an issue either. vehicle is only used to a from work

Answer
Andrew,

I would look over the tach wire installation.  If it is allowing for a second ground the coil will not fire properly.  Disconnect the aftermarket tach and see how it does.  Email me back and let me know and I will look up the specific wiring on your tach to the truck.