Have you checked that you have HT from the coil to the Dizzy Cap? Have you checked the cap and made sure that the spring loaded contact in the middle is making contact with the rotor arm? If all is ok and you have LT to the module, it sounds as though you have an issue with the internal parts which may be worn and not contacting somewhere. From my recollection (and I haven't looked at mine to confirm) there is a small wire from the module that runs inside the dizzy and screws down a bit like the points based dizzy. Is that all secure? There is a way of testing LT from there but I cant remember how without looking at mine which isn't possible at the moment.
The other thing to check is whether you have a ballast resistor. If so and you are getting spark on cranking, you may have a duff resistor that cuts power to the coil. If its rusty that would hamper it.
Finally, I notice that you are using a 3ohm coil. The 280ZX coils are 1.5ohm and when I used a 3ohm as recommended in various sources, it caused no end of problems with starting and running. It was totally cured when I swapped to a 1.5 ohm 280ZX OEM coil. Try swapping to a 1.5 to start with.