Need some help with a starting problem
My 90 will not crank with the key
I can jump the starter with a screw driver and it fires
when I turn the key to start the electrical goes dead
I have put in 2 new ignition switches a start run relay and cleaned the battery posts. If I turn the key a bunch of times it will start and then works for awhile
but then it goes dead and Im stuck for 20 min. or so unless a jump the starter
I also did notice that when I cycle the key a million times the buzzer goes off and that's my clue it will start with the key any help would be great
Thanks Robert

 

It may be a corroded connector. Try unplugging, then reconnecting all of the connections in the start circuit. Two or three times. That will clean them. Including the big connector block at the firewall.
It could also be a broken conductor in a wire. The insulation might still look OK but the copper wire inside is broken. I had that problem at the voltage regulator connector on my 90. It gave me fits finding it.
Have someone hold the key in the start possition while you check things out.
BE VERY VERY CAREFULL. It could start at any moment.

 

Put a push-button on it.