[MustGoFaster]

Stock they do not prime the FP at a "key on" event, only while cranking.

There is one potential issue with the starter trigger wire. Mitsu used a wire that is right at it's maximum capacity for the trigger wire. Age+heat can increase the resistance and make it not trigger the starter.

You could also just try hitting it with a hammer, as sitting for a few years it might just be a stuck solinoid.