Problem with my WB

[Phil Hunter]

> Does a free air test give an output of ~ 4.0V? If so
> I'd say that it would seem the DIY-WB is working
> correctly. Might want to double check the component
> values as installed. (we have been finding that free
> air checking typically comes in around 3.93v).
> 
> BobR.
> 
> A79coupe at aol.com wrote:
> 
> > I built my wide band, and finally got the bung
> welded in to the downtube on the headers.  To test
> it, I turned on the WB, waited for the led to show
> that the sensor was hot, and then started the
> engine.  The voltage from the sensor was pretty
> steady at about 3.12v.  According to the Vout table,
> this corresponds to an AF well in excess of 20:1. 
> Since the engine would not be running if the AF were
> 20:1, I know it must be wrong.  Additionally,
> according to some datalogging, I see that the stock
> o2 sensors are switching around stoich.
> >
> > I took the car for a brief drive, and under WOT,
> the WB shows 1.95-2.05v or around 12:1 AF.  This
> seems close compared to an AF reading I got on a
> chassis dyno recently.
> >
> > HELP!!!.  I need to know what to check in order to
> verify proper assembly and to trouble shoot the
> output.
> >
> > TIA
> >
> > Eric Anderson
> > Atlanta, GA

An exhaust leak upstream of the UEGO where outside air
is being drawn in by Bernoulli's law could explain it.
This is a continous problem for the Turbo Buick folks,
header flanges not sealing, welds cracking, etc. And
it doesn't take much of a leak to cause problems
either. Try listening for ticking w/ a hose or such,
but you can still have a leak and not hear it.

Also, misfires can put a lot of oxygen in the exhaust.

If the engine is in closed loop, you shouldn't be
seeing a "steady" anything for Vout if you're seeing
the EGO toggle. Maybe swap the 2 sensor's positions
and see what happens.

Any list members live nearby that could "buddy up"?

rgds,
philh
(digest)

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