[Diy_efi] changing wbo2 reading via timing

[Shannen Durphey]

Adam Wade wrote:


> 
> I was talking about a snapshot.  Static.  Thus,
> "instantaneous".  I'm sorry that wasn't clear.
It was very clear.  The voltage reading at the sensor is instantaneous.  If
I find that multiple samples of the instantaneous reading remain unchanged,
I can conclude the engine is not running.  Or that the sensor is
non-functional, or that the scope is dead, or...

> Maybe if you know the engine, and have already tuned a
> few.  You can't "smell" whether an engine is rich or
> lean any more than you can "smell" whether you have
> optimal ignition timing.
Geez... you were just talking about a rich condition causing a misfire. 
That's an eye burner.  Even if it's only one cylinder the fumes are
noticeable.  Now you're talking about differences within the operating
range of the WB. 

> 
> > And I'm not separating the exhaust gasses out of
> > individual cylinder.
> 
> But you claim you can tell me what cylinder is
> producing a transient on your WBO2 (assuming it's
> actually a measured transient, and not a source supply
> fluctuation or RMI).

It's not likely contamination or fluctuation from the source, as the source
is external to the car and self contained.  A similar effect can be viewed
on a narrow band O2 around stoich, although it's nowhere near as useful. 
At least I haven't spent any time trying to make it useful.  I can't say
I've done all the testing I could to rule out noise, but I have tested to
see that the signal is similar on different vehicles, is viewable with more
than one scope, and is consistent with the cylinder firings as observed by
forcing a misfire and viewing the results.

And I specifically said that I could not tell which cylinder was causing
the problem based on scope readings alone.  I have not tried to diagnose a
misfire to the point where I can identify which cylinder is causing the
problem by using the WB alone, and do not claim to be able to do so.  But I
can and have used the readings to tell the difference between an overall
lean condition and a lean condition caused by a misfire on one or multiple
cylinders.  

Creative and intelligent people will find ways to get the most out of their
tools.  I'm not the type to simply look at the WB output and say "That's
all I can get?  Well, ok."  I'm not tuning a car in a static situation. 
I'm not in a lab or in a room with a computer printout and a calculator
working out how to tune this vehicle.  I'm an active part of the process,
and as such I'm allowed to use all the information that is available to
me.  I don't _have_ to look at a static reading to determine engine stall. 
If the car stops running, the engine stalled.  I don't _have_ to try and
determine whether the mixture is lean to misfire or rich to misfire from a
printout.  I'm right there next to the car when it happens.  

> I suppose that depends on where you draw the line at
> "outside".  

This looking like an issue over semantics.  

Shannen

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