Winfred, tell us about your oxygen sensor cleaning

[mzarifkar]

I read in a post about you having a procedure where you clean the oxygen sensor with a brush and then flame it to clean it back to operational condition. could you explain please? would it fix a 1221 code?
Thanks!!

[winfred]

brush the tip clean if it has thick deposits on it making sure that slots are clear, then get it good and hot with a propain torch (mapp gas torch works better for cleaning as it's hotter) and then give it a shot of compressed air through the slots in the tip. this treatment can get a little more time out of a slow sensor but will not bring back a dead one, it's not hard to test the operation of a 02 sensor, with a graphing multimeter it's infact easy (just watch the screen) but you can't tell the temp range it's working in, as the sensor gets older it takes a higher temp to produce the voltage the computer is looking for, to test it get the sensor hot with the torch and with a meter scale set to 1 volt dc (red connected to the black wire and black connected to the gray) the reading should stay above 750mv with the flame on the tip, it's hard to test the reaction time without a graphing meter but a good sensor will drop to almost 0 in around 1/10 of a second with the sensor up the operating temp, the reading will be very sensitive to the flame, but like i said it's hard to test the temp range which would be the ultamate test, the sensor starts reading around 650-700* and you are testing it with a couple thousand degree flame, generally i find if it reacts quickly it's probably still reading in the right scale or close enough. if the sensor has 100k miles or more and is suspect it wouldn't be a bad idea to just get a new one, most 3-4 wire sensors are due by the book to be replaced at 60k but will often go well beyond 120k, but after a point they start costing you fuel mileage


ps not all 02 sensor codes mean the sensor is bad, just that the mixture is reading off the map

[mzarifkar]

with possibly a 115k on mine, i think it would be better to replace the sensor then. But thanks for the writeup anyway, being the geek i am i will probably end up playing with the old sensor as described anyway

[shogun]

Buy a new one, pay back period is very short due to less fuel consumption and a much more agile engine response.

In general O2 meters should be exchanged after 60k miles (for example the US Bosch made), the ones made by Bosch in Germany come with 100 k miles warranty but are more expensive.

[mzarifkar]

in all honesty i havent noticed a decrease in consumption/performance. I checked the sensor today per bentley instructions for voltage output and got a consistent (not fluctuating as it should) .6v. the kicker is that after all of this the check engine light went off, after resetting the computer no new 1221 code (yet) so i wonder if it was just the connector. If it comes back again im replacing it.

[winfred]

it ether wasn't hot enough to go into open loop, the code it still in the computer and the computer was ignoring the 02 sensor, or the heater has died in the sensor, checkable with a multimeter looking for a fairly low ohm's reading across the two white wires