You need to get down to basics and start from there. With ANY engine, the basics are fuel and spark. Check fuel pressure. This requires a rather elaborate fuel pressure gauge, but you MUST know if you have fuel pressure or not.

Secondly is there a spark? Pull a plug wire and see if it will jump a spark to ground. Do this very briefly with a helper to turn the engine over while you observe. The spark should be BLUE. If it is orange, it is a weak spark.

At this point, if the problem is spark start by pulling the distributor cap and while it's off, make sure the rotor turns. If anything is burnt or looks bad replace it. If all that looks good test the coil.

If there is no fuel pressure start by looking at the fuse on the fuel pressure relay. Check voltage at pump. If there is voltage on the pump and still no pressure, the pump is at fault.

Good luck.