[Diy_efi] O2 says rich, car runs lean.

[Gary]

The previous statement was worded poorly, or at least confusing.
I'll attempt to improve on that here. Hope this make better sense.

At stoich, a voltage of .45V (450mV) is generated. It is at this voltage
the NBO2 is designed to be accurate. Stoich will cover a range from
~150mV to at least 650mV. The high end of voltage will increase even
more as the temp decreases. To point I want to stress, a wide range of
voltage is covered with resulting AFR still remaining at stoich. Once
outside (richer or leaner) the voltage change is much less for a much
larger range of AFR. IOW, from 14.0 to pig rich the voltage rate of change 
can be no more than 250mV.

Also, to put the temp influence on a NB into perspective, according
to my data, at 900?C .880 mV will mean 10.3 AFR. At 500?C, the
same voltage means 14.1 AFR. So, without knowing the precise
sensor head temp, the AFR is at best a guess.

GAS


----- Original Message ----- 
From: "Gary" <gas- at charter.net>
To: <diy_efi at diy-efi.org>
Sent: Monday, June 12, 2006 6:01 PM
Subject: Re: [Diy_efi] O2 says rich, car runs lean.


> In addition, the further from stoich NBO2s venture, the more impact very 
> slight voltage changes will have on actual AFR, thus giving the same 
> effect as lowering resolution and dulling sensitivity.