Thanks for your interest....
The vehicle in question never exhibited any symptom other than refusing to start after being used every day for a long, long time. no codes were set...when I borrowed the ecu from another 850, that module was ruined by the suspect vehicle..i.e....when the ecu is returned to it's original vehicle, that vehicle is now disabled....
The only diff between the "donor" and the original is the last digit of the Bosch serial # which I understand to be the designate between an automatic vs. a 5 speed...which is the case....replaced the donor ecu in the second 850...it's running fine......will not try that again..
Thought about the voltage regulation issue....there are no indications, including digital voltage checks, that would indicate the regulator is bad...never blown a bulb, never witnessed dimming and or bright lights at idle or at speed...
Bear in mind that this issue of no spark was rectified for 2 solid days simply by replacing the ecu with a used module from a local bone yard....suddenly, one evening, the car died in an intersection....a quick check for spark revealed the exact same condition....very itermittent,I would say......
Anyhow, as I type, I have replaced the front harness from the ecu through the starter and on to the various sensors....my replacement wiring came from an 850 with an automatic....mine is a standard.....replaced the ecu again......IT RUNS....again....I'm looking for the color code for the neutral safety switch on a vehicle with the automatic, as I had to jump the starter due to the extra piece of harness for the different tranny.....
Thanks again for your input.....MJ