O2 sensor pullup resistor values?

[Bruce]

GM ecms, pcms, generally have a min, and max value that the O2 has to
transistion thru to considered awake
Bruce



From: "Jeffrey Engel" <jengeltx at yahoo.com>
Subject: RE: O2 sensor pullup resistor values?
> If the voltage is a steady .45v, the sensor is not
> active or is dead.  How they determine whether the
> signal transitions enough to call the sensor readings
> good, I don't know.
> HTH,

> Jeffrey Engel
> --- Peter Florance <audserv at exis.net> wrote:
> > Thanks for the reply
> > On my L jet box there is some sort of 'bias' that
> > provides .45 volts at the
> > sensor input before the sensor warms up or if it
> > disconnected. I've read
> > that's how they sense whether the sensor is working
> > or not.
> > How do they accomplish that?
> > Peter Florance

> > > Behalf Of Bernd Felsche
> > > Sent: Wednesday, December 05, 2001 8:16 PM
> > > To: diy_efi at diy-efi.org
> > > Subject: Re: O2 sensor pullup resistor values?
 > > Peter Florance tapped away at the keyboard with:
> > > > Anyone have any idea of typical ECU pullup
> > resistor (to ~ .45V)
> > > > values for O2 sensors inputs? I'm trying to make
> > a analog circuit
> > > > to average 2 sensors for my L-jet box and would
> > like to
> > > > incorporate it in the front end of the buffers.
> > >
> > > The "pullup resistors" would be infinite. The
> > sensor is a voltage
> > > cell; it provides a voltage. Attempting to bias
> > the sensor can cause
> > > damage to the sensor. If you want to level-shift
> > or add/average two
> > > sensor inputs, the easiest solution is to use op
> > amps to perform the
> > > task. Their high input impedance ensures minimum
> > current draw and
> > > sustained operation.
> > >
> > > > Also interested in any comments regarding
> > averaging O2 sensors for
> > > > dual exhaust systems and idle performance (in
> > line 6 engine)
> > >
> > > Before you go and build a simple adder circuit
> > however, look at the
> > > response curves and the consequences of what will
> > happen if one is
> > > receiving rich and the other a lean mixture. The
> > ECU needs then to
> > > see a constant switching between the levels for
> > correct operation.
> > >
> > > --
> > > Bernd Felsche - Innovative Reckoning, Perth,
> > Western Australia


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