[Diy_efi] wide band O2's

[gary]

Message> One thing I noticed is that the oe solutions from Bosch NEVER 
> describe any sort of routine calibration, as most of the current 
> aftermarket solutions claim was necessary. So it is my desire to 
> determine (if I can) HOW the oem WB02 hardware and/or control 
> strategies are so different that they do not require any sort of "zero 
> oxygen" calibration apparently for the life of the vehicle (or the life 
> of the sensor- which ever comes first! LOL

> It's been known that these ASICS do not require routine calibration 
> as they derive a trim solution based on the sensor calibration resistance. 

> I'm curious what the source/root cause of any significant drift might 
> be - normal chemical breakdown? contamination?

The ALL analog circuitry was designed for OEM applications. The 
OEM WB sensor is not subjected to the abuse it endures in a 
'performance' or 'tuning' tupe application, be it lead, or something 
less severe like AFRs on the rich side of stoich, (IOW 12.0 AFR 
or even richer) something not experienced by a sensor in an OEM 
application.   This unusual wear 'n' tear causes the WB sensors to 
drift.  Without the abuse that causes this drift, there is/was no need 
for manual calibrating/compensating circuitry in the OEM analog 
circuitry.  HTH.

GAS


----- Original Message ----- 
From: "WopOnTour" <wopontour at hotmail.com>
To: <diy_efi at diy-efi.org>
Sent: Wednesday, July 06, 2005 12:09 AM
Subject: Re: [Diy_efi] wide band O2's


> Well to clarify my own intentions/motives
> I have been searching for an aftermarket or DIY WBO2 controller 
> solution based on either the CJ120 or CJ125 for many months. It is 
> apparent that Bosch is using these in their existing engine management 
> systems, but I have yet to find a stand-alone unit or even schematics 
> to construct a complete controller (other than what's provided in the 
> Bosch datasheets) No I was told (from a usually reliable resource) 
> that the PLX controller was using these ICs. (and it just, by shear 
> coincidence, coincided with WBO2 discussions on this list)
> Does anyone know of any WB02 controllers that are actually based 
> on the genuine Bosch ICs designed to maximize their performance??
> 
> *Currently I am working with what I call my "wrecking yard" WBO2 
> solution, scamming a Bosch Motronic ME3.1 controller off a wrecked 
> 2003 Saturn VUE (with that same GME V6 discussed earlier) and 
> am using an oem scan tool to observe the WBO2 PIDs via the K-line 
> datastream.  One thing I noticed is that the oe solutions from Bosch 
> NEVER describe any sort of routine calibration, as most of the current
> aftermarket solutions claim was necessary. So it is my desire to determine 
> (if I can) HOW the oem WB02 hardware and/or control strategies are 
> so different that they do not require any sort of "zero oxygen" calibration
> apparently for the life of the vehicle (or the life of the sensor- which ever 
> comes first! LOL


----- Original Message ----- 
  From: WopOnTour 
  To: diy_efi at diy-efi.org 
  Sent: Tuesday, July 05, 2005 11:31 PM
  Subject: Re: [Diy_efi] wide band O2's


  Thanks gary
  I think I understand your concern (and don't disagree)
  But as the controller is maintaining pumping cell and heater current in a 
  closed loop fashion, wouldn't this allow for drift or skew that occurs over 
  time? I'm curious what the source/root cause of any significant drift might 
  be - normal chemical breakdown? contamination?
  Thanks for sharing your thoughts
  Regards
  WOT

    ----- Original Message ----- 
    From: gary 
    To: diy_efi at diy-efi.org 
    Sent: Tuesday, July 05, 2005 9:38 PM
    Subject: Re: [Diy_efi] wide band O2's


    As I understand it, WB controller (analog) circuitry that relies on 
    a sensor calibration resistor without manual calibration, does not 
    allow for sensor outputs as they drift over time/use.  The sensors 
    drift, but the calibration resistor stays the same.  I question the 
    accuracy over time/use.

    GAS
      ----- Original Message ----- 
      From: WopOnTour 
      To: diy_efi at diy-efi.org 
      Sent: Tuesday, July 05, 2005 10:08 PM
      Subject: Re: [Diy_efi] wide band O2's


      Wouldn't it depend on what ASIC was chosen to provide nurnst and 
      pumping cell current control and AC-DC measurement?...  It's been 
      known that these ASICS do not require routine calibration as they 
      derive a trim solution based on the sensor calibration resistance. 
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