1990 Oldsmobile 98

There is a new starter in it and new battery and alternator but u can go out and start vehicle just fine and shut it off two seconds later and go to start it back up again and it wont even turn over the starter wont even ingage so then u turn key off again and try it again and nothing happens and then shut it off and try it again and it will start up. Idk what is wrong but the battery is fine cause all dash lights come on and everything like that. Any suggestions
December 14, 2012.

There are two voltage circuits at the starter solenoid. One is battery voltage, hot all the time. The other feed comes from the ignition switch, probably a purple wire, Goes hot with key in the crank position, is routed through the neutral switch for automatic tranny. Any testing at the starter, make sure tranny is in park or neutral and the parking brake is set. Check the actual voltage reading.

Dec 14, 2012.