I have a 1986 iroc it wont crank over but can jump the starter and fires right up any ideas of what it could be

 

1st guess is battery.

 

jump the starter? You're talking about from the main positive wires on the starter solenoid to the small terminal with the purple wire on the solenoid? If that's the case, it's looking like a starter switch under the column. Before you go changing that out because a part was mentioned, test for power on the solenoid purple wire when the key is turned. Car on jack stands, a test light and a helper to turn the key is required. If there is no power then start troubleshooting backwards from there. Seen at the bottom of this diagram http://austinthirdgen.org/mkportal/m...ine_wiring.gif