"Biff Byrum" <bbyrum9@foothill.net> wrote:
> As for keeping that aft sensor, probably so. The fore sensors are rated at
> about 80 to 100K, but as Bernd has said, does the aft sensor even affect the
> pulse width algorithm? It's stated task is to measure Cat efficency. But
> what the heck? Those are good prices. I paid a little more for mine.
Yep, the primary function of the downstream sensor is to monitor
the health of the cat. (Probably the only function in many vehicles.)
Bernd has mentioned in this thread that it has some effect on the long
term fuel trim. I don't have an inside connection or know the
programming, so I'm not sure how much of an influence the downstream
sensor has over the fuel trim or how they are using it to influence
the trim. I have read that the long term fuel trim can only alter the
base map by about 25%, so the correction to your actual air/fuel ratio
is probably pretty minor I would suspect?
At any rate, although a failed or failing downstream sensor might
play some factor in your fuel economy (how much of a factor I do not
know), it shouldn't really affect the drivability. By contrast, when
the upstream O2 sensor goes out, you're relying on the maps with no
correction (except for the previously memorized long term fuel trim),
so drivability problems in that case would not be unexpected, and fuel
economy should noticeably suffer.
--
-Jon-
.- Jon Steiger -- jon@dakota-truck.net or jon@jonsteiger.com -.
| '96 Kolb Firefly, '96 Suzuki Intruder, Miscellaneous Mopars |
`-------------------------------- http://www.jonsteiger.com --'
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