Correct A:F Ratio @ WOT?

[Bernd Felsche]

Jon Davis tapped away at the keyboard with:
> I have wondered about real vs. indicated AFR... some mods on my
> car seem to do real well for about a week, but the power slowly
> disappears over time. I wondered if I was changing the combustion
> and screwing up the self-learn in my ECU. I thought about making a
> circuit with a variable offset on the O2 sensor, to tell some fibs
> to the ECU and see what happens. Anyone know the esr of an oxygen
> sensor offhand, around 100k?

It may be "broken" if you try to run a resistance measuring current
of any magnitude through it for any length of time.

One measures the output voltage into a high impedance (>1Mohm).
The ECU is probably looking for the switching voltage about 0.45
volts, which is equivalent to stoich.

> ----- Original Message -----
> From: "Stephen Webb" <swebb at netlab.uky.edu>
> Sent: Monday, October 01, 2001 11:19 PM

> > gradient") cause lower voltages.  Changing timing can change the
> > combustion, and burn more or less of the mixture, leaving less
> > or more oxygen in the exhuast.  The "indicated" AFR (inferred
> > from exhuast oxygen content) will thus stray from the actual AFR
> > input.
> >
> > Maybe that's why people say O2 sensor AFR gauges are a poor way
> > to tune.


-- 
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