83 f100 won't stay on

[FordNoGo]

So I have a 83 f100 302 with EEC I just put a rebuild engine and when attempting to start it starts then I let go of the key to disengage starter the engine dies. So I tried to start again (cranking) it starts while I still have the key on to start (cranking still) I can rev up the rpms and hold the rpms where ever (running but starter is still cranking) but when I let the key go (key in run) engine dies. What do you guys think? Where should I start to find the problem?

 

[SuperCab]

Check to see if you're getting power to the coil when the key is in run maybe? Or maybe a bad ignition switch? Others will probably have better ideas.

 

[FordNoGo]

Check to see if you're getting power to the coil when the key is in run maybe? Or maybe a bad ignition switch? Others will probably have better ideas.

I am getting power from the connecter to the ignition module in run and to the coil which puzzles me why it won't stay on. the next thing I was gonna try was to start the engine and have someone disconnect the starter at the relay to see if the engine does stay running with out the starter but I need another person I'm by myself right now

 

[FordNoGo]

UPDATE!!!
So I bought a chiltons repair manual and me and a buddy ended up finding the fusible link from the battery had a open an wasn't getting power to the EEC relay so we cut the wire long enough from the EEC relay to connect the wire straight to the battery and now the truck runs an stays on PROBLEM SOLVED!!! Yay