You need to start over with your question. We've learned from someone else you changed the harness, have an MSD, etc.
Otherwise, the best answer to your question of why your engine turns over but doesn't get any spark is, "We have no freakin' idea."
Try this:
I have a B---- engine that is OBD -----. I recently changed the wiring harness because ------. It ran fine for ----- days, but one day while ------ it ----, and it hasn't been getting spark since. The only thing I did between the time it was running good and when it died is ------.