O2 Sensor current?

Bruce Plecan nacelp at bright.net
Tue Mar 23 18:00:08 GMT 1999


-----Original Message-----
From: Roger Heflin <rah at horizon.hit.net>
To: diy_efi at esl.eng.ohio-state.edu <diy_efi at esl.eng.ohio-state.edu>
Date: Tuesday, March 23, 1999 11:44 AM
Subject: Re: O2 Sensor current?

Working with the CCC ecms is just about fruitless.
Been there, done that, got numerous T-Shirts.
Lots more to be found in the carbs metering calibrations.
Bruce


>
>
>On Tue, 23 Mar 1999, Gary Derian wrote:
>
>> Wouldn't you want to operate leaner than stociometric for better economy?
>> The AIR should divert to the cat when warm and not affect the O2.  Part
>> throttle ping can be caused by insufficient EGR.
>>
>> I don't think a simple resistor in series will work as you want.
>>
>> Gary Derian <gderian at oh.verio.com>
>>
>>
>The air (at least on my vehicle) is injected in at the headers, so the
>air should affect the O2 readings, at least I cannot see how it would
>not affect the O2 readings.
>
>I would not think a simple resistor would work either, at least not
>that low of resistor, and if they are using a resistor, they are
>probably getting both open circuit voltage, and voltage through the
>resistor/current through the resistor.   I don't think with just one
>you can properly figure out battery charactistics.
>
>I like the other idea of measuring the resistance of the O2 heater,
>and calibrating that to get egt temps.    Then I would need ot get a
>pcmcia AD card, and hook that up, and get the aldl data recorder
>software working together with that to get one data stream.
>
> Roger
>
>> > I have been trying to see what my O2 sensor draws for current.  For an
>> experiment, (
>> > I am trying to make it run slightly richer across the board ) I
installed
>> a 10K
>> > resistor in series with the O2.  At idle with or without the 10K I read
>> .57 idle,
>> > hot, closed loop.  That seems high to me.  If I rev it up, the voltage
>> drops to
>> > closer to .4 to .43.  It is somewhat stable, not swinging like I
expect.
>> Is this a
>> > sign of a bad O2?  I am using a DVM to measure.  It is an GM O2 sensor.
>> (BTW, I have
>> > swapped O2 to another from my 91 Bonneville and have no changes)
>> >
>> > What I see is a 1.5mV drop across the 10K resistor, and when I rev it,
it
>> increases
>> > to 22mV.  This is a very small amount of current, it this to be
expected?
>> >
>> > Can someone give me some advice on this system?
>> >
>> > The car is a 85 Cutlass, CCC, 77 Olds 350.  The AIR and Cat have been
>> removed (reason
>> > I am trying to richen).  The car runs pretty well.  But when hot there
is
>> a nasty
>> > part throttle ping, light throttle, when at WOT or heavy throttle, or
at
>> very light
>> > throttle, no problem.  I have been told that if the AIR system is
removed
>> this will
>> > cause it to be lean, as the O2 is expecting a certain amount of air to
be
>> present, so
>> > it would lean it out then.
>> >
>> > EGR is working properly.  I am using an 82 307 intake with the improved
>> EGR tube
>> > extensions.
>> >
>> > Am I missing something obvious?  Will the AIR removal or missing Cat
cause
>> this
>> > problems?
>> >
>> > Thanks for any help!
>> > Tom Martin
>> >
>> >
>>
>>
>




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