I would look at anything spliced into the original wiring harness.
Think about replacing crimps with soldered and heat shrink tubed splices.
Clean all the ground connections. (engine, transmission, body, thermostat housing?)

won't fire:
-do you have spark?
-do you have fuel? (do you hear the fuel pump spin for a couple of seconds when switching from ACC to ON?)
-check timing belt (broken? jumped a few teeth?)
-check timing (in spec?)
-pull and re-gap spark plugs

take care,
ChrisS