diy-EGOR

[bcroe at juno.com]

My 2 sensors have resistors of 3.58K and 14.97K.  I 
assume these are used to calibrate the ECU to the 
particular sensor plugged in, since the wideband 
sensors are not completely consistent in performance 
from one unit to the next.  According to the info that 
used to be at  www.vb.co.za/  it's to compensate for 
variations in the heater resistance to get consistent 
temperature

I see my sensor with 3.58K resistor has a 3.1 ohm 
heater, while the one with 14.97K resistor has a 2.8
ohm heater resistance cold.  Guess we need to tear 
apart a Honda to see what that means.  Maybe some 
others could add some points to the above.  My guess 
is all heaters require the same POWER, but I don't 
know how much

OK, what model Honda was that again I need to steal
the ECU out of to run this experiment?  Bruce Roe  

On Sun, 25 Feb 2001 12:50:15 -0500 "Bruce Plecan" <nacelp at bright.net>
writes:

> Has anyone figured out what for sure the resistor that is molded in 
> to the
> connector is used for?.
> Or has any tried gathering the various values?.
> Anyone interested in trying to?
> 
> Last I heard, there wasn't even a memory clear procedure when 
> changing
> sensors on the oem Application.   Seems like as more are built we 
> can start
> to use fixed values on things.
> There just has to be a set of fixed values, IMO, for all of the 
> pots, I mean
> Honda is actually doing it..
> 
> Thanks
> Bruce

> > Before hooking up that expensive NTK to your newly built circuit,
> > it is nice to be able to test it out. I have a heater circuit 
> built and
> > did the setup and test this way.
> >
> > Use a 3.3 ohm (or there-abouts) resistor of 5 to10 watts in place
> > of the NTK heater. Setup a current meter in series with this 
> resistor.
> >
> > Power up the circuit and set pot R19 (or R15?) for a current
> > of 1.2 A. (this is the 'current limit' pot).
> >
> > Change 3.3 ohm to a 10 ohm resistor (or add in a 5.6 ohm). Setup
> > a volt meter to read the voltage across the 10 ohm resistor. 
> Adjust
> > R20 to give 10.0V across the 10 ohm load resistor.
> >
> > The Vss_volt_adj (Q7-C) should be low (< 0.6v) with the 10 ohm
> > resistor. And should be > 5v? with the 3.3 ohm resistor load.
> >
> > If you have a regular 'ole heated O2 sensor around, it can be used
> > to do a final test of the circuit. Hook up the heater only and 
> power
> > up the system. By monitoring the heater volts & amps, along with
> > the Vss_volt_adj, make sure that the heater current never goes
> > above 1.2A, and the heater voltage nevers goes above 10.0v.
> >
> > As the heater heats up, the voltage will increase until it reaches
> > 10.0v, then current will drop maintaining the max of 10v. At the
> > 10v trip point, the Vss_volt_adj will also go low.
> >
> > Once I have the Ip circuit built, I'll see what can be done for 
> setup
> > and test there. This one looks to be a mite more difficult.
> >
> > hth's,
> >
> > BobR.
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