Check for disaster first. 1) not really a disaster but inconvenient; see if the timing belt at the top rear of the engine is broken. It runs the fuel injector pump. You can see it without removing anything. 2) this is a disaster: pull the top half of the sheet metal timing belt cover at the front of the engine. This belt drives the camshaft and if it breaks pistons and valves run into each other and bend things as well as probably breaking the camshaft bearing supports. In either case the engine won't run. If these are ok then look for the wire to the front of the injector pump that causes the solenoid fuel valve in the pump to stay open while the ignition is on. It could have fallen off or have an open or short somewhere in it. Diesels are pretty brute simple but expensive. If they have compression and get fuel in a reasonbly timely fashion they usually run. The D24T is actually a pretty good engine and can do good work and lots of it. If it did not swallow valves and you can make it run you probably got a good deal.

Hope this helps.