I do appreciate your input...all ground connections are clean and solid..the voltage at the primary side of the coil never drops below 12+ while cranking...the vehicle does NOT start with key in the on position...jumping the starter motor to the battery with the ignition in the on position produces same results...no spark while cranking...as I stated, the only spark occurs as the engine turns to a full stop, with the starter completely out of the circuit....the vehicle has effectively destroyed 3 different, perfectly functional ecu's...I know this because I can produce the same condition in another 850 by swapping the ecu... the initial replacement of the ecu resolved the issue...THAT replacement is now junk...it lasted 2 days...once the vehicle has smoked the ecu, I find that there is no 5 volt signal available at the cam sensor connector, only 12, 12, and ground...this is wrong, and is the RESULT of the problem...the return signal is required for timed spark while starting....I'm left thinking that my harness is compromised in such a way as to create whatever condition is possible to render the ecu inoperable...has anybody ever seen a harness issue create such havoc?? btw..Volvo states that this model year ecu is non programmable....just replaceable...Thanks again for your response
MJ