I'm without wiring diagram, but the only thing I can imagine would stop the car would be for the fuel pump/fuel pump relay circuit to go dead. I think the heater circuit for the O2 sensor is also powered by by the fuel pump relay. It shouldn't matter which way current goes through the heater circuit, but if it were taken to ground the relay or fuses probably wouldn't take it long.
The possibility exists that you sent power up the O2 sensor lead which could take out the KE controller but those cars run pretty well without electronic mixture control so I doubt that is keeping the car from running.
I would check the fuses involved with the fuel pump relay and the relay itself. Good Luck.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician