[Shotimes] Oxygen Sensor Question

[George Fourchy]

On Sat, 20 Nov 2004 21:45:31 -0500, Leigh Smith wrote:

>Has anyone ever had new O2 sensors change emissions or increase gas mileage?
>Where the sensor had not obviously failed(codes)?

I changed an O2 sensor on my '89 Turbo-coupe when the book said to, at 85,000 miles.
 It made no difference in the way it drove or got fuel mileage.  It retired at
200,000 with that second sensor in it, and got good mileage all the way to
retirement.

Lowrider went to 225,000 with its original sensors.  They never threw a CEL.  As far
as I know, there were no codes stored for them at all.  The symptom of their failue
was increasing poor fuel mileage in town, but the same (or close) good mileage on
the freeway.  The reasoning for this was the fact that when they wore out they could
not switch back and forth from sensing a rich mixture to a lean one fast enough to
adjust for the various power and throttle settings in a city environment.  On the
freeway, there wasn't that much switching back and forth, so they could keep up with
events.  It would run rich in town, since rich mixtures couldn't be detected quickly
enough to adjust the mixture more lean.

After the new sensors went in, it returned to getting decent mileage in town, and
highway economy got a little bit better....city--15 or less improved to 20-22 (no
hot-rodding, just commuting).  Highway improved from 24 to 28, using cruise and
traveling 300-400 miles between stops.

George

George