after about a year building a 414 stroked 6.0, i finally got the engine in the car, I connected the battery and the starter starts turning over the motor without the key ever being in the ignition. I checked the wiring on the starter and its stupid proof, two wires, a big on and a small one so i couldnt of got them switched. I followed the wire harness and everything seems to be in its correct location. I took off the starter (wires still connected) and connected the battery and everything was fine, it wasnt until the starter was bolted back up that it started to go off again. (maybe bolting up the starter grounded it?) I thought it was the starter solenoid but everything checks out ok....does anyone have any ideas?? thanks for your help

 

when it is bolted up its grounding it allowing it too spin over. i wouldnt hook up the keyed hot wire(the small one) and just the constant hot and try to ground the starter if it turns over then it is the solenoid and you just need to get a new starter.

 

well it actually was the starter relay