Will not start

For months I have had I intermediate battery drain. Sometimes I could go for weeks without a issue and some days I would need a jump three or four times.
I changed my alternator, starter and went through several batteries. Also change my distributor cap button and wires and plugs along the way.
I am now at a complete no start. Along the way I have found that ho2s bank 2 Sensor 2 was the wrong sensor installed and was back feeding the ground through the system's the entire time. I searched and searched and searched for this negative ground feed and never could find it.
When my nose start began the engine would turn over and fire for just a moment. I replace the crankshaft position sensor and now it is just a complete no start with turning the motor over continually with no fire or gas. Two separate scanners cannot connect to the OBD2 and I am at a complete loss as to what else to check.