O2 sensors

[BradyEng at aol.com]

In a message dated 95-12-23 18:35:27 EST, you write:

>I need some info on oxygen sensors...  I have installed two O2 sensors
>in my  header  collectors  (350  V8).    These are attached to two LED
>bargraph meters for monitoring purposes  only  at  this  point.    The
>readings  I  get  from the sensors are not really agreeing with what I
>see from engine operation.
>
>The  sensors show basically full lean (<100 mV) at almost all throttle
>openings, which I cannot see because the engine runs fine, has lots of
>power, etc.  The engine has 30000 mi  with  no  problems,  if  it  was
>actually running this lean it would have eaten head gaskets or pistons
>long before  now.    The  only time I really get a change in O2 sensor
>output is under deceleration (throttle fully closed)  at  which  point
>the bargraphs show full rich (>950 mV).
>
>2. the  engine  is running on propane fuel, is it possible that the O2
>sensor is not  responding  with  the  correct  reading  for  rich/lean
>because of the different stoich point for propane...
>
>With regards to this point, if this is the case,  is  it  possible  to
>correct  the  O2  sensor  output  to  reflect the correct voltage with
>alternative  fuels  such  as  propane?  Any info on how to calculate a
>correction factor (if necessary) would be appreciated.

I would like to second this question on O2 sensors.  It appears to me that
the garden variety used in production autos are basically go-nogo gauges for
rich-lean.  However, meters with O2 sensors are sold which are reported to be
useful tuning aids and accurate to ~0.5 A/F.  Does anyone have comments on
prices, sources, and performance of the sensors used in the aftermarket
systems?

To answer a question in this query directly Bob Behn wrote an article in
Turbo Bike Volume IV Number I on air fuel ratio meters that included data for
alchohol and propane.
Turbo Bike is available from Joe Haile Enterprises, PO Box 8000725, Valencia,
CA 91380-0725, Tel 805-255-3426.  Bob Behn sells an A/F meter @ RB Racing
1625 W. 134th St., Gardena, CA 90249, Tel 310-515-5720.  Meters are also
available from K&N @ 714-684-9762.  I've seen the K&N in operation on a
street KZ1000 (4 cyl air cooled 2 valve motorcycle) with a header.  It took a
while to warm up, but sure speeded up the jetting process.

The short version is that stoichiometric is stoichiometric on the gage or O2
sensor, although the actual A/F ratio changes with fuel .  Rich and Lean Best
Torque are between about 86% and 92% of stoichiometric.  The problem is that
O2 concentration just doesn't change much below stoichiometric.  CO becomes a
much better indicator, but I havn't heard of real time sensors for this.

I'm sure this topic has been covered before in this forum, but I would very
much appreciate it if it was discussed again. 

Thanks

SBrady