Are all O2 Sensors created equal?

[Marc Swanson]

> 4-wire sensors can -sometimes- be wideband sensors, and there are two
> kinds of wideband sensors if I remember right.  However, more
> commonly 4-wire sensors are used simply to get a good ground
> reference.  Two pins for the heater, one for signal, one for signal
> ground.  3-wire's are grounded through the exhaust, which is usually
> OK.



To add to Brett's post, there are some 4-wire sensors that while still
providing a 0-1v output like all other sensors, produce a better range
than other o2 sensors.  As a data point, Nate Stuart and myself have
been using generic 3-wire Bosch o2 sensors and we've noticed from our
data logs out of the 034 EFI ecu that the range didn't appear to be as
wide as the 4 wire sensor that Javad had been using in his car.

Example:  generic bosch 3-wire sensor:

http://www.newtsplace.com/90tq/plotter.php?file=nstuart_10ms_scaler.CSV&dir=.

4-wire o2:

http://www.newtsplace.com/90tq/plotter.php?file=JShadzi_STGII_IC.csv&dir=.

(look at the pinkish line on the graph)
--
-Marc
87' 4ktq
88' 90q
www.mswanson.com/audi