Oxygen sensor

[David A. Cooley]

At 10:31 PM 12/26/98 -0500, you wrote:
>Put together the oxy sensor bargraph display discribed elsewhere here, and 
>am puzzled @ the display.
>
>At moderate & heavy accelleration, indicates about 800-900mv, holding 
>steady; @ cruise, or any part-throttle condition, bops back & forth from  
><100mv to about 600, nice & regular.  This checks w/ scantool reports.
>

Verry normal

>Question: is the O2 sensor involved in moment-to-moment injector decisions, 
>or just to activate a trouble code should things get seriously awry?
>
>Would a capacitor/resistor combo to integrate the input to the 3914 yeild 
>any meaningful info @ cruise?  Cute display, but for what?  Or is something 
>broke on my vehicle??

The O2 is involved with moment to moment injector decisions... The PCM
commands an A/F ratio and the PCM looks for the O2 sensor to be crossing
the stoich point on the O2 sensor voltage... If the PCM see's the O2 sensor
staying below 450MV or above 450 MV, it will set a trouble code.
You could probably use the res/cap combo, but it would have to be isolated
by about 10 meg ohms from the O2 sensor itself or it will load the O2
sensor enough to cause problems with the way the PCM see's it and will set
a code.

Later,
Dave

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           David Cooley N5XMT           Internet: N5XMT at bellsouth.net
     Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
       I am Pentium of Borg...division is futile...you will be approximated.
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