JD 410C Start, Run 3-5 seconds, quit

This machine was used very little in previous years. We started to move it to a new location when just before loading, it quit. Looked like it was out of fuel, so we added a few gallons (Diesel). It restarted, ran fine, got loaded onto trailer. 20 mile trip. It would not start when we went to unload it. Using either, we could get it to run, but not stay running. We have since installed a new fuel filter, bled the fuel filter housing at the top, and have cleaned and checked air intake filters, all ok. Now it consistently starts no problem, and at any throttle setting, but it only runs for 3-4 seconds and then stops. I have cracked open the injector lines at the top of the engine, have checked to see if there is sufficient fuel supply to the fuel pump, and have tried to run it on quite a few different days and quite a few times each try. Always same result: start fine, run 3-4 seconds, quit. If I try to restart it immediately after it quits, it will restart, but run a bit shorter on time. If I leave it sit for even 30 seconds or more, it will start and run 3-4 seconds. Is there anything electrical that would cause this? I noticed a wire going to the injector and disconnected it at a quick connector and the machine would not start at all. Reconnect, and same 3-4 seconds run. Could something have shaken loose during the 20 miles we trailered this machine? Please help. Thanks