I have an 850, I think the EZ-129K type system that gives no spark. I have another 850 that ran right up to the point of the moment the timing belt broke, so I think it would be reasonable to assume all the ignition components function. I have switched into the no-spark 850 these items:

1. coil
2. crank position sensor
3. camshaft position sensor
4. ECM (middle one in the case I think) but did go back to the original one when this made no difference.
5. tried a different coil high tension wire

All connectors look clean and wiring shows no damage anywhere that I can find.
All grounding straps I could find look great.
Car cranks over fine, dash lights come on as they should, the distributor rotor is turning indicating the timing belt has not given up.

This may or may not be related, but the data link connector led comes on when I push that button with the key on and the probe in socket #2, but I get no response.

Does anyone have suggestions for this seemingly elusive problem>?