[Diy_efi] O2 says rich, car runs lean..

[Michael Richards]

On Mon, 12 Jun 2006 02:28:38 -0400, Gary Spooner wrote...

The narrowband thing is not really an opinion, it's based on scientific
fact. Narrowband sensors are designed to discriminate between richer
than 14.7 and leaner than 14.7. Nothing more. You can get a vague idea
of the actual AFR is by looking at the actual output away from the
switching point but it is by no means accurate.

OEMs have been using narrowband sensors for years because it is in a
fixed and tested location and since the tuning is fixed the temps are
also predictable. In the original poster's case we're dealing with a
modified engine producing more than stock output numbers. Very difficult
to predict the temps of that sensor and the setup is outside the OEM's
designed application.

-Michael

> Regarding narrow band 02's I have to disagree with the opinion about
> narrow band inabilities to provide and accurate indication of 02
> content. This sensor has proven over the years to maintain 02 content
> within emission specs where the algorithm is not biased to look for an
> alternate backup if closed loop info fails. Narrow band sensors are
> capable of millisecond response and range even to the point of
> indicating incomplete combustion from a cylinder or cylinders if
> observed on a scope with resolution 200m/sec and .25Mhz.
> 
> Tuning accompanying the use of a scanner to indicate 02 voltage,
> interrogator values and long term conditions, using the factory
> computer, have found tuning to be very easy and let the computer scrub
> the converter even at idle speed. Factory constants have to be changed
> but the result of the adjustments is impressive. I have setup numerous
> boats and even tailored a rat?s nest of mismatched parts creating
> algorithms that work. Don't jump on the wide band wagon (lol) yet.
> Narrow works well to...
> 
> Gary/RPM Research
> rpm-research.com
> 
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