Oxygen sensors

[Nate]

Let me clarify...

This is on a 1985 Chevy Sprint, made by Suzuki originally. (the car I put 
a monitor on).

It uses the O2 sensor to richen and lean the mixture in a closed loop.

THe sensor really works good because I tried leaning and enrichen the 
mixture manually and it changed quite rapidly!

Once it's hot, it reacts very quickly. Not that you would have the 
computer make rapid changes, I would average it (and it looked like they 
did too) and slowley change the mixture.

I remember when I first started messing with stuff like this, I would 
forget that the CPU was so fast, and would have to re write my code when 
I connected it up to the real world.

Here's the simple monitoring equipment idea I used...

Connect a Radio Shack "bar graph" display to the sensor output (0 to 1V), 
through a resistor (10K I think) and put a CAP about 33uf on it (this 
takes out any varances). This gives you a idea of what the sensor is doing.

Then conect a LED (1K resistor in series) to the "lean/rich" selenoid, 
and it will vary as the mixture is leaned out etc.... (you watch the 
pulse width modulation with your eye).

It's interesting to watch it work.

Have fun...