Mr. Walker said what I would get around to if all else fails.
So far, you are coming back so you have not failed us.

If you read the posts between Art and I, you will realize that not everyone knows everything.
No one has a "long distance magic wand" but sometimes we get lucky and your problem matches our experiences. That's it!

You purchased the Power Stage on your on and since not being the smartest thing to do we all regret that happening to cause a frustration.
The parts house is not so much. I doubt they will let you return it. They are an expensive and remote Tool Box.

In Art's post to me, he says, the Power Stage has brains. If you look at the pictures of the one he provided me or us, the traces going ever which a way and it looks like a brain. Especially, that very center chip with really fine wires. He got that opened up and it still works.
This is Truly amazing, if you have ever unsealed something that was not supposed to be ever repaired or seen into again. His point overall is they are rather rugged.

Your car is a lot bigger and those wires look like blood veins to me. You probably think you are staring into an abiss but even an abiss has its areas named.
Art is more like a Brain surgeon, as you can tell from the gloves in his pictures. (:-) I myself it's all about being grubby! Very seldom I wear gloves but I have gotten better.

My tricks were learned mechanically and are not with sophistication at all.
Art knew to call me on my statements in your post. He knew I needed help to understand that a capacitor or an old term "condenser" does more than just suppress spark across a set of breaker points or a flick of a wire.
It shifts the relationship of time and current to voltage like a Beaver Dam in a water stream.
Most of the time I did get a weak spark unless I opened the points manually. I never realized what I was doing but a condenser was on them.
Now this is all a layman's analogy because a condenser is a simplistic device in a voodoo magic world to me. The Power Stage, as you can see, is more than a non-clicking relay or a set of breaker points.

My point is despite the frustration if you will take the time to learn and ask enough questions you will come out "down stream" with a whole lot more behind you.
Yes I have the book he recommended that I purchase. It covers a lot of German or Bosch ways of engineering things but it is a collaborative work. Unfortunately, it got left at my other house in a drawer of my reading and restroom. (:(
I'm sure there is a reason he is working from the ICU side of the circuitry and pokes the Power Stage with pins instead of a voltmeter. He is humoring me, a bone head, that my idea has some merit.
Art is the man who has answers and maybe a "wand or two" but like any "good teacher," he lets the student work a little, as he did once, to earn those wands!

Yes that fuse in not on the car at that battery location.
It was moved by '90 or '91 to the fuse panel inside of the car. It was due to problems or an engineering consolidation, I believe?
Like Mr. Walker states, it appears the issue is not there since you have fuel into the engine.

Check Art's web site at Cleanflametrap.com site or search the Brickboard related to ICU and a non firing ignition.
I might mistaken but I think there might be a connector related to the ICU that he inspects for corrosion on the nineties cars.
You might ask him directly, if he see's your post. Adding better clues to work with helps but there is no straight forward "wiggle your nose" fix.
Developing a little bit more skill set using a voltmeter with BB guidance is what you need to work for.
Lady Luck was never a fair playing mythology.

All People on the Brickboard borrow and share. I deserve my hard knock lessons for being who I'm! (:-) all in all, it makes for a better thought process.

Don't be frustrated and go with flow. In my case, it helps to be fluid! (:-)

Edit:
I spent too much time on here and Art already responded. You see!

Phil