Check voltage at fuel pump cutout relay pin 4(yellow wire) should be connected to the inertia switch and should be 12v. Pin 3 on relay should be 12v when relay is activated through the oil pressure switch. Jumper that oil pressure switch out to remove any doubt as to whether it is working. It is kind of tough to change out, but you can unsnap the connector pretty easy and put a jumper across it. Then turn key to run position to pickup the relay and fuel pump. As I understand there are two versions of the 7.5 liter "hot fuel" systems on 1983 Fords. The only documentation I have is a Haynes Repair Manual No. 36058 which covers 1980-1996 pickups and broncos. If you look at the "please read" stuff on this forum I believe that there is something that shows the dual fuel pumps on our trucks.