Repairing And Rewiring 1930 Bx On A Porch Light?

I have two Porch Lights controled by in indoor wall switch next to the front door. One light works fine, the other not at all. I unscrewed the fixture from the log cabin front wall and tested the fixture by plugging the two wires into an extension cord. The fixture is fine. I noticed that the BX coming out of the wall, its shield entering the box and fastened with a spring loaded clamp which closes on the shield by a screw on the outside of the box, contained two wires, a white and a black. Both were somewhat burned and rotted so I had to untwist the sheild of the BX several loops, about 6" inches to reveal crumbling skins and paper wrap insulation. Removing that I black taped both wires, cut off the dangling shield which could no longer be clamped to the box. To connect the shield to the box I drilled a set screw hole in the shield, added a screw, a ground wire and made contact with the box. The fixture still wouldn't come on. I work at Home Depot so today I brought home a 3" ground wire with a green screw built into one end and a U-shaped end on the other. I thought I could make a better connection to the metal box or make a connection to the iron fixture itself. I left the box at Home Depot so I guess I'll try that tomorrow. Thanks so much for your help. Doctors might do this one day to help patients at their home. They probably already do. Oh well, thanks again from your prompt response. I clicked "Not Helpful" because I wanted to signal that I still have not solved the problem. [email protected]