[urq] Running Rich issue solved!
Louis-Alain Richard
larichard at plguide.com
Mon Feb 26 16:08:51 EST 2007
Bravo Mike ! One less to worry about. Now, Keith, a little effort
please :-)
Mike,
2 questions come to my mind:
- Did you sealed any engine parts (valve cover, water pump, etc.) with
RTV silicone recently ? The standard silicone was responsible for O2
sensor failures in the eighties, IIRW.
- Did you test the dead O2 sensor to confirm that it is indeed dead as
a doornail ? If not, you can do it easily with a propane torch. Read
this procedure from this site:
http://www.gnttype.org/techarea/ecmsensors/O2sensors.html
Testing O2 sensors on the workbench.
Use a high impedance DC voltmeter as above. Clamp the sensor in a
vice, or use a plier or vice-grip to hold it. Clamp your negative
voltmeter lead to the case, and the positive to the output wire. Use a
propane torch set to high and the inner blue flame tip to heat the
fluted or perforated area of the sensor. You should see a DC voltage of
at least 0.6 within 20 seconds. If not, most likely cause is open
circuit internally or lead fouling. If OK so far, remove from flame.
You should see a drop to under 0.1 volt within 4 seconds. If not likely
silicone fouled. If still OK, heat for two full minutes and watch for
drops in voltage. Sometimes, the internal connections will open up
under heat. This is the same a loose wire and is a failure. If the
sensor is OK at this point, and will switch from high to low quickly as
you move the flame, the sensor is good. Bear in mind that good or bad
is relative, with port fuel injection needing faster information than
carbureted systems.
ANY O2 sensor that will generate 0.9 volts or more when heated,
show 0.1 volts or less within one second of flame removal, AND pass the
two minute heat test is good regardless of age. When replacing a
sensor, don't miss the opportunity to use the test above on the
replacement. This will calibrate your evaluation skills and save you
money in the future. There is almost always *no* benefit in replacing
an oxygen sensor that will pass the test in the first line of this
paragraph.
Louis-Alain
> Finally figured out my "super rich" running problem. It was the Oxygen
> sensor! I replaced it last year just as a "preventative maintenance"
> thing, so I
> didn't think it would be bad. Luckily I try and stock extra parts for
> times
> like this and I had a new OX sensor. I was ready to replace the
> injectors and
> the WUR!. So perhaps if someone else has a rich (or maybe lean)
> condition, try
> the ox sensor. It's a bitch to get at too.
>
>
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