OBDII, O2 sensors......(via digest)

From: Sean_Meldrum@ittauto.com
Date: Mon Sep 14 1998 - 07:17:35 EDT


>
>>Its been a while since I looked at this stuff but if I remember
correctly, 0
>volts would mean 100% oxygen, and 1 volt would mean 0% oxygen.
>
>Exactly the opposite is true. More voltage indicates MORE oxygen.

  Hmmm... You sure about that? My FSM says otherwise:

     <snip>
> Its possible that the FSM is wrong I suppose; stranger things have
>happened. I assume that if the FSM was wrong, CC would have sent me
>a correction? OK, how do we find out for sure? :-)

     Nope...FSM is correct. Cat does NOT remove oxygen. Your front O2
sensor readings will flucuate around 450 mV (14.7:1 fuel/air) as the
computer constantly tries to adjust the mix. The rear sensor will read
approxiamately 10% of that amount (can't verify this percentage in all
driving conditions as this testing was done at idle and revvin' the motor
while parked....those readings had the rear sensor outputting approx. 35-41
mV). The CKC circuit design was loosely based on info given to me by
someone at Casper Electronics (I think that's the right name). They
produce O2 modules like this for Fbody's and Impalla SS's. Jon has taken
the circuit to the next level by adding the 6ohm resistance circuit for the
heater portion. My intentions were to leave the sensor in place thus not
needing to make any changes to the heater portion of the circuit. This
voltage divider ciruit works by the O2 sensor remaining in place as it will
need the mV input that the O2 sensor outputs.

Jarrod's Mustang *did* get a CEL but it didn't effect drivability so he
left it alone. He sold the car b4 installing the prototype CKC dual
exhaust module I sent him. I have heard of Fbody guys not gettin' CELs
with offroad pipes in place. I know of two '97 Daks with no cat that have
no CEL problems and one '98 that gets 'em.

This module has been bench tested using a power supply and works perfectly.
Hopefully Jon can prove it's road worthiness.

TTYL

****** 97 RPM Dakota - 14.98 @ 91.76 ******

sean meldrum
Email @ Home: spm@c3net.net
Email @ Work: sean_meldrum@ittauto.com
webpage: http://surf.to/dakota-forsale



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