Alfa Romeo Repair: Alfa 75 ignition failure without warning., random faults, ac volts

Question
I have a 1987 Alfa 75, 2.5litre V6 with a history of ignition failure(that's why i got it cheap).On receipt the car had a flat battery and when I fitted a new battery the car started immediately. I thought I had a good buy. So I drove it for a week until it just lost power and stopped one day and refused to restart. A roadside mechanic checked out the coil and distributor and while there was power to and from, there was no spark at the plug leads or coil lead...so I towed it home. The hint was that the Ignition Control Module under the coil may have been at fault but on exchanging that with a known good one it still failed to fire. All the earth leads were cleaned and tightened. Another I.C.Module was fitted (just for luck) but still failed to start. Meanwhile all the pesky self diagnosis warning lights on the dashboard are showing incorrect and random faults in everything from all doors being open to.....I don't believe this is tied in with the ignition though. And then on two occasions of the many times I turn the engine over...just on the offchance that it might start....it actually did, and purred like a kitten for about 3 minutes before turning itself off and not starting again....to this day.
Have you heard a story like this before?

Answer
This is a common story with poor grounds. Did you also do
the grounds under the dash. Also, there are two units that
control the ignition plus the sensor in the distributor.Thus,
the first thing to do is test the output of the distributor
with a digital multi-meter set to ac volts. Disconnect the
plug on the side of the distributor, there are 3 connections.
Turn on the starter and test for pulsing voltage from 2 of
the connections. If it tests good see if she starts again and retest
when engine will not start. But first, with a fully charged
battery (12.66 volts), diconnect the negative lead of the
battery for 30 minutes then touch the postive lead with the
negative lead (the negative terminal of the battery still
not connected) for 3 seconds and then reattache the neg.
lead to the neg. terminal of the battery.