My guess is the transistor in the ECU responsible for operating the relay has been destroyed. One way to do that instantly, in this circuit, is to jumper either 86 or 30 to 85 (the blue/green) when attempting to start the car.

You can test whether my guess is correct by connecting a jumper from ground to 85 (instead of your 86-87a jumper). If the car starts and runs, you'll need to repair or replace the ECU. This may have been done before on your car, as I think the 83's came stock with the -503 ECU until '84 when the -510 ECU was used in new and replacements.


--
Art Benstein near Baltimore

Never put both feet in your mouth at the same time, because then you won't have a leg to stand on.