Use a new battery.

<12v means the car purposely won't start.

Also replace the CAS. The sensors after 20 years are getting flakey.

Neutral switch etc doesn't affect spark. The debugging guides in the factory manual will tell you this.

If you've checked everything else...please put the battery on the charger overnight, and try again tomorrow.


ps (edit) also check you are still getting 12v at the ECU during cranking. As I'm sure you are aware, the 1200 has 2 terminals for ignition, one for cranking, and one for running. Please bridge these two, to create an ignition always pin.