Two thoughts.

First, ground a test light, probe the output side of the coil - the one with the red/white wires - and crank the engine. Before cranking, the light should stay on. While cranking, the light shoud flicker steadily. The flickering light generally means that the ignition parts that sit behind the coil - the CPS, the power stage and the ECU - are operating properly.

Second thought. You should have two red/white wires on the output side of the coil. One goes to the power stage, the other to the tach. The tach wire is there even if you don't have the instrument. Remove the tach wire and try to start. If the car starts, the tach wire is grounding somewhere, and preventing the ground interrupt necessary for the secondary ignition system to function.