I change distributor and still no spark on spark plug what is the problem?

and yet again , another reason for...............nevermind........

i have a 1993 3.0 and i had no spark,but it cranked over for some reason if the thermostat wires or thermostat,broken,it will not start,the mass air flow sensor is bad it will not start.check thermostat,and wires one for hot and cold,maybe it will start.