What causes the mysterious ST1300 FI light that I see threads posted on?
And the search for a spare ECM that pops up?
Overwhelmingly, it is a fault code 25 or 26, which is a problem detected in the knock sensor system. This seems to affect 2007 and older model years. Honda changed something in the ECM for the 2008 and later model years which seems to have fixed the problem. The search for ECM's is usually to deal with this. I don't recall much in the way of people looking for an ECM for 2008 and later model years.
I have to wonder how much of what you write is because carburetors is what you are familiar with, and what you know and understand. I used to work as GM factory certified mechanic in a GM dealership. I grew up with carburetors, and started working in the dealership when there was both carbureted and fuel injected vehicles. Consequently I had to be trained on and learn both systems and how to work on them. By the time that I left, there were no carbureted vehicles, they were all fuel injection in Canada starting in 1985. When I left that dealership, all of the younger mechanics had never worked on a carbureted engine, didn't study it in school, and didn't know anything about them. I can tell you that all of them would find diagnosing and repairing a fuel injected engine to be much easier than a carbureted engine, because it made sense to them and because they understood how it worked and how all of the various parts interacted. They had no idea how a carburetor works, or how to diagnose it. Give them a carburetor for a full strip and rebuild and they would shake.
I personally have no doubt that a fuel injected engine is far better at controlling the fuel delivery and is more reliable than a carbureted engine. The problem with them has nothing to do with their difficulty to diagnose or repair. The problem for people like yourself who will try to fix a vehicle on the side of the road, is their difficulty to diagnose and repair on the side of the road compared to doing the same with a carbureted engine. There is a greater inability to diagnose a greater number of symptoms without special tooling, even if that is only a scanner and a multi-meter, as compared to a carbureted engine. In a garage setting where the diagnostic tools are available, competent younger mechanics now a days would have no more difficulty diagnosing and repairing the fuel injection system than old timers had repairing engines aspirated with carburetors. They have all grown up with electronics and understand it, so it is not intimidating to them. They would find a carburetor intimidating.
This assumes all things being equal of course, such as competence and skill level.
i.e. An incompetent mechanic working on a carbureted engine that had a sophisticated induction system such as what was in place just before fuel injection took over, doesn't fair any better diagnosing a fuel delivery/induction problem on that carbureted engine than an incompetent mechanic who is working on a fuel injected engine does.
I suspect that XX number of years from now when vehicles have been electric for a long time, everyone will look at fuel injected ICE engines and wonder how they work, won't be able to diagnose them very well, and will refuse to even consider looking at a carburetor because that would be beyond foreign to them.
