how do you backprobe an o2 sensor.....do i disconnect the sensor and stick the probing wires in the back? if so which wires do i put the probe wires on?

 

nipper

What are you trying to see? I'd think you'd really need to connect on oscilloscope to see the signal. If the sensor is heated, you'd have to leave the connector plugged in I would think so the heater could function. If you have an o-scope I'd just probe each wire on the harness until I saw a signal. If it's heated one (or two) of them should be ground, one should be +12V, and one should be the magic signal, not sure of the amplitude, maybe 1v-pp.

 

I think it's generally suggested that you do not use those probes that pierce the insulation.