"What about "Limp Home Mode"? when will it default to run that way? trouble seems to be most likely in pulse path or pulse generation, right? That's where I'll look next."

Forget "Limp Home Mode" and the LH FI system for now. You have a no-spark problem, and the FI system can't cause that. In my previous post, I explained that the CPS pulses to EZK and EZK's propagation of those pulses to the LH ECU is working—as shown by the FI operation. Does that make sense to you? Or am I assuming it's simpler than it appears?

Your coil should be Bosch # 0-221-122-364* (stamped on the bottom). FWIW, I've never had one fail in 40+ years. But you can test it manually by using a grounded test wire to substitute for the Power Stage like this:

1) Pull the main coil wire end from the distributor and connect it to a spark plug that you can observe (the plug body must be grounded).

2) Temporarily remove any wires from coil terminal #1

3) Turn the Key to II, and use the free end of the grounded test wire to "make and break" contact with terminal #1. (Be prepared for some harmless sparking at terminal #1.)

The test wire should "trigger" a spark at the plug every time it's removed from terminal #1, which is just what the PS should do when and IF it gets "triggered" by the EZK CU.

You don't have to be real fast with this. Be methodical enough to satisfy yourself that the coil is (or isn't) capable of generating a spark. And let us know how it goes.

* Volvo part # would be 1317810-8 or the superseding # 9438228-0.




--
Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.