o2 readings

[Diane Stowe]

Thanks Walter, I'll check that out tomorrow.

you are correct, I just 'popped' that o2 sensor in, and the engine right now
has a quadrajet on it. Also in practice, it's running way too rich. So I was
puzzled by these readings. I was using 2 different dvm's one a fluke.

thanks, Diane
----- Original Message -----
From: "Walter Sherwin" <wsherwin at home.com>
To: <gmecm at diy-efi.org>
Sent: Monday, January 01, 2001 6:47 PM
Subject: Re: o2 readings


> Thinking out loud here.....sounds like you have just recently added this
O2
> sensor to your conventional carb'd quadrajet setup, and that the O2 sensor
> is not now (nor has it ever been) a part of a computerized feedback loop?
> Also, with what are you measuring the small O2 sensor voltages, and what
is
> that device's input impedance?  Normally, a feedback O2 sensor
(conventional
> zirc) would be part of a larger signal conditioning circuit within a
> computer, and would superimpose small voltages overtop a 450mv carrier
> signal.  I'm not entirely sure what you would observe if you were to
measure
> the raw unconnected O2 sensor output voltages with say a normal DVOM.
> Perhaps someone else has tried this and can relate to your numbers.
>
> As for the wiring of your sensor, use your DVOM to check continuity from
red
> to black and then red to grey (you later called that one white).
Whichever
> combo has the least resistance is your heater circuit pair.  The remaining
> wire (probably the grey) will be your signal wire.  To measure the
resultant
> output voltages, you'll need to connect your test device from the signal
> wire to the shell of the O2 sensor.  Your test device had better have at
> least 10 Mohm input impedance, with closer to 100 Mohm being best (as per
> Fluke's published data).
>
> Walt.
>
>
>
>
>
>
> > the o2 sensor is a Sorensen 779-7020, I bought it some time ago and just
> had
> > a bung welded in.
> >
> > I do not know if this is from a gm tpi application or not, I thought
that
> > they were all pretty much the same.
> >
> > does the wiring I have look right ? red=+12v, black = gnd, and white is
> the
> > sensor ?
> >
> > it varies between 11.09 at idle up to 36 mv with partial throttle. It
> takes
> > about 45 seconds or less for it to warm up and give me some readings.
> >
> > thanks, Diane
> >
> > thanks, Diane
> > ----- Original Message -----
> > From: "Programmer" <nwester at eidnet.org>
> > To: <gmecm at diy-efi.org>
> > Sent: Monday, January 01, 2001 3:30 PM
> > Subject: Re: o2 readings
> >
> >
> > > You're using a 3 wire heated ? Ok--happen to have the part number
> > > handy ? With the numbers that low, the ECM is going to command
> > > longer pulse on the mixture control solenoids--and go full rich.
> > >
> > > Lyndon.
> > > -----Original Message-----
> > > From: Diane Stowe <dianes at speakeasy.org>
> > > To: gmecm at diy-efi.org <gmecm at diy-efi.org>
> > > Date: December 31, 2000 2:14 PM
> > > Subject: o2 readings
> > >
> > >
> > > >Hello, a question. I thought I would test my newly installed 02
sensor
> > > prior
> > > >to my installing the new map tpi. I have a quadrajet on it now.
> > > >
> > > >I presumed that the red and black were 12v+ and -, and that the gray
> lead
> > > >was the sensor reading. The sensor is welding in a bung that is about
> 5-6
> > > >inches below the passenger side exhaust manifold.
> > > >
> > > >anyway, with 12 to the o2 heater, which is on all the time, I get
11mv+
> > at
> > > >idle and somewhere between that and 36+ mv on driving up hills or
> > > >strightaways.
> > > >It never goes below that, or negative. Is this what I should be
seeing
> ?
> > my
> > > >rpm never gets above 2300 due to the 700r4 and the 2:88 rear I have
in
> > the
> > > >car. I am trying to track down the cause of the poor fuel mileage,
it's
> > > >about 10 mpg. that with a custom grind crower street cam, a new
timing
> > > >chain, a edelbrock performer and recently 21/2 inch pipes from the
> > exhaust
> > > >headers to the front mufflers and the installaiton of a crossover
pipe
> > > after
> > > >the transmission. sadly none of these changes have helped much. I'm
> > > assuming
> > > >that the quadrajet is just running too rich, however I am not sure
from
> > > >these readings.
> > > >
> > > >thanks, Diane
> > > >
>
>
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