A wideband O2 sensor is only useful if a computer will treat it accordingly.
Essentially, a "standard" O2 sensor is really just set up to read rich/lean. Rich is above 0.45V, and lean is below 0.45V. The computer is really just trying to make sure that it runs so "close" to the correct A/F ratio that the signal quickly goes above and below that 0.45V threshold, which told the computer that the A/F ratio was averaging out about correctly. If the O2 sensor spent a lot of time below 0.45V and didn't go above very often, the computer would try to fatten up the mixture accordingly. That's how the PCM acts.
The voltage is not linear above & below the 0.45V - not even close. It's a wild curve, but 0.45V is pretty much always equates to a 14.7:1 A/F ratio. Look at this:
Unfortunately that graph makes the response look linear and predictable, but it isn't nearly as clean as that graph makes it look. But you get the idea.
In the old days some of the boosted cars (i.e. 1980's turbo Grand Nationals) would pick a particular voltage and tune accordingly. Sometimes 0.810V, sometimes 0.850V, etc., but it had to be reviewed every time the sensor changed, the driver would have to set expectations for the new sensor accordingly.
The advantage of a wideband is that it can give a much more linear signal, so that you can interpret a more precise A/F ratio. That works great on an A/F ratio gauge, or for computers which are set up to read that signal and adjust accordingly. But since the PCM in our cars is set up for the "standard" O2 sensor, the PCM would be confused and would not react accordingly.
I am in the middle of installing EFI onto a 1973 Buick, and that will have a wideband O2 sensor - because the computer I'm using is designed to use it. It will tweak the tune accordingly.
You can't just swap a wideband O2 in place of a standard O2 because the computer won't know what to do with it.
