Hi Jim,

For openers, go here and get the 1994 850 wiring diagram:
www.matthewsvolvosite.com/downloads/1994_850_wiring_diagram.pdf

I'm not sure if it's complete or not, there being multiple sites that offer
the Volvo 850 wiring diagram (my 1995 book is 41MB)

The Volvo wiring diagram is terrific, system diagrams and component locations.
Look in the index for multiport fuel injection EZ129K

and find the ignition parts on the lower right portion of the schematic.
You will see that there's an ignition module (ECU) and a power stage.
and it should be much easier for you to troubleshoot. Everything is carefully
documented.

The index explaining component ID starts at page 200 in my book. It helps to print that out so you can understand the schematic.

The schematics page is followed by a parts location page

They will have a pictoral showing what pins are what.

Soon you will ignore that Chilton's :-)

Bill