O2 sensor renewal

[bigmeat]

Has any body every tried renewing an o2 sensor by heating it with a torch to clean up the tip. I need a new o2 sensor and was going to pull one out of a low milage civic.

Topic

[EricTheCarGuy]

Never tried it. I don’t really recommend it either. O2 sensors are cheap enough. Why not just replace it with a new one?

[Mathieu]

Don’t use a torch is do nothing to clean the sensor.

The catalyst is clothed whit burn oil ash inside the o2 sensor. So if you try to bur It whit a torch, the ash il not burn at all because It already burn. You see to use a spray for sensor. It’s call a sensor cleaner. That mean, the cleaner will leave no residue inside the sensor. It’s crucial, because above 600 `C, you expect to see chemical residues burning if It’s possible and also stick ash for ever until you fund the right solvent to remove It.

HOW AN OXYGEN SENSOR WORKS TO GENERATE ELECTRICITY

The O2 sensor works like a miniature generator and produces its own voltage when it gets hot (about 600 degrees or higher). Inside the vented cover on the end of the sensor that screws into the exhaust manifold is a zirconium ceramic bulb. The bulb is coated on the outside with a porous layer of platinum. Inside the bulb are two strips of platinum that serve as electrodes or contacts.

The outside of the bulb is exposed to the hot gases in the exhaust while the inside of the bulb is vented internally through the sensor body to the outside atmosphere. Older style oxygen sensors actually have a small hole in the body shell so air can enter the sensor, but newer style O2 sensors “breathe” through their wire connectors and have no vent hole. It is hard to believe, but the tiny amount of space between the insulation and wire provides enough room for air to seep into the sensor (for this reason, grease should never be used on O2 sensor connectors because it can block the flow of air). Venting the sensor through the wires rather than with a hole in the body reduces the risk of dirt or water contamination that could foul the sensor from the inside and cause it to fail.

The difference in oxygen levels between the exhaust and outside air within the sensor causes voltage to flow through the ceramic bulb. The greater the difference, the higher the voltage reading.

An oxygen sensor will typically generate up to about 0.9 volts when the fuel mixture is rich and there is little unburned oxygen in the exhaust. When the mixture is lean, the sensor output voltage will drop down to about 0.2 volts or less. When the air/fuel mixture is balanced or at the equilibrium point of about 14.7 to 1, the sensor will read around .45 volts.

http://www.aa1car.com/library/o2sensor.htm

Attachments:

• heatedo2sensor.gif

[John B Kobberstad]

Actually if I’m not mistaken what you are describing is the method to test an O2 sensor (if you don’t have a good scanner or a lab scope) by heating the tip and checking the the voltage produced at the wires. With the 4 wire sensors 2 of the wires serve to heat the sensor when the engine is cold started, the other 2 will produce a voltage which should go above and below 0.5V quickly. Do not keep the torch on the tip constantly or the sensor will be destroyed.

[bigmeat]

It all started when the cooling fan chaffed the wiring harness. Any way I changed the oil the other day and wiggled the o2 sensor harness and reset the mil and so far it is working corrtly.

[EricTheCarGuy]

Thanks for the update. Keep us posted if things change.

[college man]

thanks for the update.keep us posted.

[Author]

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