O2 voltages

[Bruce Plecan]

> Here's one for ya--is the O2 really for keeping the engine AFR corrected,
> or is it to keep the fire burning in the converter ?

The converter.
I worked on a car at the PW where the voltage characteristics were different
then the oem one, and the ecm thought things were just fine and at 14.7
commanded when the actual was 15.2

 Which does the EPA
> feel is more important--which does the manufacturer feel is more important
?

The EPA is all about the EPA, even the Supreme Court has stated that.
Manufacturers have to meet the EPAs regs., to be able to sell cars.
IMO
Bruce


> I'm just throwing this out for wideband comment...
> Lyndon.
> -----Original Message-----
> From: Bruce Plecan <nacelp at bright.net>
> To: gmecm at diy-efi.org <gmecm at diy-efi.org>; diy_efi at diy-efi.org
> <diy_efi at diy-efi.org>
> Date: October 2, 2000 11:00 AM
> Subject: O2 voltages
>
>
> >
> >These are my observations and first impressions, and as I distill things,
> >and get more time with the WB I'm sure they will be revisited, and
expanded
> >upon.
> >One thing that I'm totally clear on now, is how useless the oem gm O2
> >sensors are, for anything other then their intended use (as being rich /
> >lean, switches).
> >I was able to run the WB on several cars, with several different
monitors,
> >and watch the displays.
> >With all the filtering averaging etc that the ecm and scanners do, there
is
> >time delay from when an event happens till when reported, and datalogging
> of
> >what the ecm is doing includes all the filtering.
> >
> >What's this really mean?.
> >You still need to know tuning, and tune up.
> >When using the oem O2 for tuning, your quessing,    it will just
> >****reliably**** tell you something when there is a major problem, and
> maybe
> >the magnitude of problem, ie the oem sensor voltage dropped to .3v during
> an
> >event,   and the WB showed just slightly richer then room air!.  *****So*
> >what* looked* like* a* reported* leanness* (with the normal data logging
> and
> >scanner) was* actually* an* ignition* event*....
> >
> >The actual output of the oem sensor is nothing like the output of the WB
as
> >far as resolution of cylinder firings, as far as variance in cylinder to
> >cylinder.
> >
> >I'd also wondered why GM went to watching crankshaft accleration rates
> >rather then synching the O2 to cylinder firings, well the above covers
why
> >you can't do it.
> >
> >Oem ones work excelent for what they are designed for.
> >WB's **can** be an excellent assist, to monitor trends in what you engine
> >like *relative* to performance evaluations,  and report back to you what
> the
> >engine ****LIKES****.
> >ie.  if it runs EXCELLENT (best), at 12.25 AFR, then you know, 10.75 is
> just
> >wasting gas.  Just getting back to doing what the engine *wants* rather
> then
> >you wanting it to run at xc.y:1 AFR cause that's what you think it needs.
> >
> >The old saying of speed cost money has taken on a new meaning if you want
> to
> >solely rely on electronics to avoid having to learn much about tune-up.
> >
> >Now, if ya think about the above, and how it applies to the world as we
> know
> >it many things get clearer.
> >
> >Hope ya'll find this as interesting as I do.
> >I ya don't want to hear about it lemme know.
> >Bruce
> >
>
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