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Subject:Re: 11MPG!
From:Joshua Van Tol
Date:Tue, 1 Dec 1998 19:34:43 -0600

>Joshua Van Tol wrote:
>>
>> >Check your tail pipe.  Full of soot, right?  It's your O2 sensor.
>> >Disconnect it.  Shud take care of the problem immediately.
>> >
>>
>> Should read, replace it. The oxygen sensor, when working correctly, will
>> help, not hinder your fuel milage.
>
>Actually, if the sensor is dead and the tailpipe is full of soot, the
>soot probably killed the sensor.  SO, best to find the real source of
>problem.  Any sensor (or any other part for that matter) that doesn't
>live up to its life expectancy shouldn't just blindly be replaced.
>You're just asking for the new sensor to die an early death as well.
>

True. But most of the time a dead sensor is just worn out, or damaged from
lead fouling. Sooty oxygen sensors can often be revived by heating the tip
with a propane torch, to burn off the carbon. This is also an excellent way
to test the sensor. Simply connect your volt meter to the sensor, heat the
tip up, and, once it's hot move the flame on and off the tip and see if the
reading changes. You may have to shut off the torch and use raw propane to
displace enough oxygen to get a reading.

>Now short term, if disconnecting the O2 sensor helps, then by all means
>do it.  BUT, consider it a short-term fix while you dig around for the
>real cause.  If disconnecting it helps, no soot in tailpipe (that was
>someone other than the original questioner's comment), and the O2 sensor
>is probably at the end of its natural life, then it could be the whole
>source of problem and replacing it will fix everything.

Ayup, very true.

Joshua Van Tol -- jjvantol@lear.csp.ee.memphis.edu