I would like to thank everyone beforehand. Here is where i stand, I have old blue (73 F100 302 V8) parked for a while, when i would attempt to start it, the starter would get stuck (it would keep cranking). I jumped the gun and replaced the starter and solenoid. (being careless, when i was uninstalling the solenoid, my wrench touched the horn relay and caused a spark and blew a fuse) When i finished installing the starter, solenoid, and fuse, i proceeded in connecting the battery cables but as soon as the battery cable touched the terminal it sparks and the truck starts cranking nonstop w/o keys. What can i do to fix this, i made sure to install all wires in its appropriate places.

I'll see if i can upload any photos this coming days but for now please advise!!!!

 

TIP:

1. Remove the negative battery cable terminal from the battery if working on the underhood starting system. See, there would have been no (ground) path back to the power source (battery) to complete the circuit.

I'd say you probably have a bad ignition switch.

 

Sound advise and I 2nd on the ignition switch.

 

Check if there is voltage on the 'S' terminal (Starter Relay/Solenoid). If there is volts with the ignition switch NOT in start position, then it's most likely the Switch.

Alternatively, pull the 'S' terminal to see if it continues to crank... Might be a brand new Starter Relay/Solenoid Dud!