That said, if you absolutely *must* (again, not recommended), you'll need:
* A complete understanding of your vehicle's ignition system: You need to know how the computer interacts with the distributor, coil, and other components. A wiring diagram is crucial. A mistake could fry components or cause damage to the engine.
* A suitable replacement ignition system: This would typically involve removing the computer-controlled components (like the ignition module that's likely controlled by the computer) and replacing them with a non-computerized system. This might mean sourcing a distributor and ignition coil from a non-computer controlled engine of a similar vintage. Finding the right parts and ensuring they're compatible will be difficult.
* Extensive mechanical and electrical knowledge: You'll need to be comfortable working with automotive wiring, understanding electrical circuits, and working on the ignition system. This isn't a beginner project.
* A wiring diagram: This is absolutely essential to trace the wires and understand how to disconnect and re-route them safely and effectively. You'll need a wiring diagram specifically for your 1985 Dodge D100 with the relevant engine.
Even with all of this, the resulting system will likely run poorly, be unreliable, and fail emissions testing. The computer's control is integral to the efficient and safe operation of the engine. If you're having problems with the ignition system, it's much safer and more effective to diagnose and repair the existing system or replace the faulty components rather than attempting to bypass the computer entirely. Consider consulting a qualified mechanic instead.
