95 JEEP YJ WILL NOT START

I BOUGHT A 95 JEEP YJ RUNS FINE WENT TO GET READY FOR ETEST. NOTICED THE O2 SENSOR WAS BYPASSED HAD WIRES FROM AN OTHER O2 SENSOR AND THE WHITE AND GREY WIRES WERE CONNECTED. I BOUGHT A NEW O2 SENS0R AND PULLED OFF THE BYPASS WIRE JEEP WONT START.PUT THE BYPASS WIRES BACK ON RUNS FINE.