The video is no longer up, it was a cool O2 sensor test. it showed how the O2 sensor is basically a fume snifer, NOT a oxygen sensor, ( a misnomer name) it does NOT sense oxygen at all, it only sense a fumey exhaust rich mix. Call it a "Gas Fume Sensor" to be more descriptive.

The video that was taken down ? It showed how when the mechanic put a gas soaked rag onto the O2 sensor, it made the air/fuel ratio gauge go to 800 millivolts, when he took off the gas soaked rag the O2 sensor went to 100 mv on his Air Fuel ratio gauge that he was selling. SHowing you how it works. The O2 sensor signal is a 0 to 1 volt signal, so we deal with millivolts 0 to 100 mv. 200mv is lean, 800mv. is rich. Most cars have a standard air/ fuel ratio mix called Stoichiometric of 14/1.( 550 to 600 mv) Inwhich means 14 parts air to 1 part gas fumes. 18/1 (200mv) is a lean mix, 12/1 is a rich mix ( 800mv)

So when we add our Hydroxy Gas, it completes the burn and blows apart all the hydro carbons into nothing and we have now a clean burn and NOT a fumey mix, no more hot burning fuel down your exhaust manifold. Your CIT temp. goes down by 1 or 2 degrees f, so does your AIT temp follows suit. The O2 sensor needs a EFIE or the more modern Volo FS2 or FS3 circuit, does it for you.

Another good explanation of how the O2 sensor works. A typical mechanics explanation, but he does not mention the gas soaked rag, he just explains why you need it.