In ~2005 I worked with a world-renowned expert on industrial automation and computer control of machines. He drove a 1989 Mercedes 300 sedan with a manual transmission, which he claimed was the last car made with no software in it at all. These two facts are not un-related.
By the 80s electronics were common with fuel injection, but I consider them more like factory controllers than what we call a computer. They're little 8080 variants running closed loops and activating or deactivating output pins
pre 1997/8 Dodge 2500/3500 diesel trucks have mechanical engines in them. Other than the starter you really only need one other wire... goes to the shut off solenoid.
