Hi Nautilus88 and welcome to Kzrider,
Thanks for the kind words. Yes, I agree, the simplicity of the final design can hide the amount of work it took to get there. I find it's really easy to make a really complicated solution, and that solution appears to have taken a lot of work. It's exactly the opposite most of the time. Throwing a bunch of parts at a problem looks impressive, but it's often a shortcut.
Regarding the 4-pin modules:
I have pretty much abandoned working with them because there are so many different manufacturers now, and they all can easily change the module's operation with a simple firmware change without notice, and none of them have a datasheet to begin with. It's a designer's nightmare, really. It's like designing a guitar for mass-production, but your neck supplier keeps changing the tone-length randomly without any notice.
20 years ago, most/all modules were based on the Wells DR100 and were actually made in Wisconsin. Now they can be made anywhere and in many different factories. The original DR100 conformed nicely because it was based on the Motorola MC3334 chip, for which there was an actual datasheet. Most new ones are not, and most likely the chip will become unavailable, if it isn't already. The new ones most likely use the ubiquitous micro-controller which is a firmware based design.
The only reliable, simple test I could come up with is the 9v battery test. But it requires the module to be removed from circuit. (I see it looks like you soldered the modules into the wiring.)
Your CBE4 looks like there is no ground tab on the side with gray plastic. This is promising since the older CBE4/CBE4P were from the 1.25v family (DR100 family). The newer, non-conforming CBE4/CBE4P modules have a little ground tab on the side. At least the ones I bought had the tab, and they were black plastic.
Also, regarding the solder (you've obviously had experience soldering to components! ) , be aware that some modules don't use the bolt-holes as the actual ground. The real ground point is the heatsink on the back. The bolt-holes become grounded when a mounting bolt pinches the bolt-hole's metal tube against the heatsink on the back. If there is no bolt going through the bolt-hole, the heatsink may not make good contact with the bolt-hole. This results in a flakey ground which is difficult to diagnose.
Here's a link to the test page and more details about HEI modules in general in case you haven't seen it.
s3.amazonaws.com/gpzweb/Ignition/HeiModules/HeiModules.html
There are many websites that store old, outdated versions of my webpages. The only one I keep current regarding the HEI modules for Kz's is the following one (at least for now).
s3.amazonaws.com/gpzweb/Ignition/GPZgmHEImod.html
I am slowly working on ignition circuits that will replace the HEI-based ones. They will use discrete parts so will be a bit more involved parts-wise, but the parts will be non-changing with datasheets, and will likely be much cheaper than the HEI modules anyway.
So far I have only finished the coil tester.
s3.amazonaws.com/gpzweb/Ignition/CoilTes...ilTesterIgbt555.html
Next will be a points-driven module, as that should be relatively simple.
Then I'll start on KZ electronic ignition modules.