This is one of the wierdest problems I've run across- 89 5.0 FI usually fires immediately,Today it doesn't and second attempt the Starter runs on.Solenoid stuck closed. We get a new solenoid.Same exact thing again! Lots of fiddling,jumping ,head scratching-Then noticed the very nearby coil wire clicking-to ground,Hmmm.Repair coil wire connection at coil, Then test the hell out of it and no more prob.
Anyone ever see a high voltage short circuit lock up a starter solenoid(relay) Before??? Thanks,Please reply !

 

Never have seen that before, but electricity is just a theory. Glad you found the problem. Welcome to the board.