At 05:18 AM 3/27/99 , you wrote:
>The O2 sensor interacts with the amount of oxygen in the exhaust stream and
>produces its own voltage form 0 to 1 volt, if I remember correctly, less
>than 0.5v indicates a rich fuel mixture (greater than 14.7:1 air/fuel ratio)
>& if the voltage is greater than 0.5v it indicates a lean mixture. I would
>think it would be fairly easy for someone to create an o2 emulator, all you
>would need is a clean 1 volt DC source through a rheostat. Using resistors
>you should be able to reduce 12vDC (13.5vDC approx. charging voltage) down
>to 1vDC into a rheostat (like a car radio volume control) & through a low
>voltage meter (so you could monitor the voltage). More voltage = More fuel =
>more power (to a point). just a thought ;-)
Unfortunately, its a bit more complicated due to the error checking of
the PCM. The biggest problem is that, while its true that the PCM uses the
O2 sensor as an input to help determine how much fuel to spray into the
engine, it also uses it as an output in the sense that when the sensor
reads rich or lean, the computer sprays less or more fuel, respectively.
However, after it does so, it watches the O2 sensor, and if it doesn't see
a change in the A/F ratio, it figures "there is something wrong here...".
(It assumes the sensor is broken.) It'll test it a couple of times, then
light the MIL (and would probably go into open loop, I would immagine).
-Jon-
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