I do a lot of auto work, between restoring cars to repairing my own. But modern fuel injection systems run on a razor’s edge of tolerances and often getting to some part requires dismounting a turbo, which is all sorts of pain in the ass, and not something I’d recommend for an amateur.
The only cool thing is the wiring harnesses and everything are fully analog so like, you have fuel injection mechanically, i mean that in itself is cool. it's just a pain
My tractors are something I always marvel over, besides the starter you don't need any power. I have an old Cat diesel that doesn't even have an electric starter! Uses a small gas engine (called a pony engine) to start the large diesel engine, and the gas engine uses a pull start, very similar to a lawn mower engine.
They always have direct injection into the cylinder as far as I know. Maybe in the early 1900's they did manifold injection but I don't think so.
It's just a total different concept.
How the metering is done (IE How much fuel to meet load) though may have been similar, I am not sure. I 'asked a friend' on this one, since I am really unfamiliar with diesels in general.
And there are some engines that are indirect injection (called IDI). I've been on the hunt for a 90s 7.3l IDI. They're gutless without a turbo, but slap a pair of turbos on and it makes a heck of a towing machine. But I don't know as much about diesels, partly because they just never break the way a gas engine will. I've rebuilt a few gas engines, diesels just seem to be made of tougher stuff.
I have always stuck to American muscle and diesel tractors. The amazing simplicity of those machines has always attracted me. I love that I can hold a complete understand of the entire vehicle in my head. I'm sure you can even for modern vehicles, but they're not simple at all!