Yesterday I desided it was high time that my motorcycle had an o2 sensor, so after a trip to every auto parts store in town looking for an 18mm nut with 1.5 thred, I stoped at the exaust shop and got a weld in bung that fit my used single wire o2 sensor perfectly, a few days befor hand I stoped at radio shack and picked up a cheap muliti meter that would read 0 to 2 volts, and checked out the o2 sensor in the flame of a propane torch to make sure it worked, and to cook off any residue that was left on it from being used in a car, after seeing that it would read up to .960-ish volts while in the flame, I was happy, then all that was left to do was braze on the bung, drill a hole thru the exaust pipe, thred the sensor in, and extend the wires for the volt meter, the engine has to run for a little less then a minute on this simple sensor for it to start working fully, a heated sensor should start giving you a reading within seconds of the enigne starting.
the sensors output is dc voltage, up to nearly 1 volt, I figure .920 is running about right, .960 I've only seen a few times for a few seconds, and anything under .850 I figure is lean, and at .700 and under, it sputters, now I'm not sure exactly what voltages the computer is looking for, but I thought this was fasinating, and I've been useing it on my motorcycle for reading the o2 content of the exaust to see how much o2 is being used in the burning of bio-diesel mixed with gasoline, to tell if my engine is running lean from the fuel not being burnt, I also of course want to tell if the bio-diesel has an affect on the 02 sensor, as far as fouling it.
now if you don't want to add another o2 sensor to your car, you should be able to look at your wiring diagram figure out what wire the computer reads the sensor with, and tap in to that wire, making sure to get good solid soldered connections, and to seal them compleatly or they will corrode, and screw with your cars computer, then you too can see how rich, or lean your car is running, and find out things like if it really does go in to a lean burn mode when you take your foot off the gas.
if .45 volts is ideal, then I guess I'm running really really rich?? but that doesn't make sence, I tune my idle by ear, with the tac, and with a vaccum gauge and it runs best at .910 volts, and sputters any leaner then that, and from reading the spark plug it's running perfectly, maybe my o2 sensor is weird, it is after all from an '84 civic that had a carburator.
Something must be up with your readings because 1 wire and 4 wire o2 will only report up to 1.1 volts, with .45 considered stoich. The thing though is that when they "report" .45 they're constantly jumping between .1 and .8, that could be the issue?