diagnose it, specially if not an intermittent fault (about 1300 ohms between coil terminals in M50, both terminals open to third shield wire)

With a tester with frequency reading, you may be able to get a signal cranking the engine with the CPS unplugged to DME, CPS is a magnet inside a coil, when the steel tooth approaches it, the magnetic flux grows stronger and induces a voltage at coil terminals. Generally, also a small AC voltage reading will appear in the coil terminals when cranking.

Javier