How often should one replace the o2 sensor? Once a year; or once a couple of years or is it after a specified milage?

R.K.

 

Really, just replace it when it fails. They're rated for 80-100,000 miles or so - they'll last a REALLY long time.

Dale

 

Dale... how do you know if it does fail? I just have a dp, catback, and intake...

thanks.

 

I thought because of all of the performance mods that I have done to my car that it would "wear" out faster. Thanks for the responses.

R.K.

 

i wanna know too

hey which o2 sensors u guys go with???

universal or oem???

mike

 

I believe the ECU will throw a code when the O2 sensor goes out. O2 sensors generate voltage, up to 1v, and that's what the ECU sees. Over time, as the element in the sensor gets clogged and tired, the voltage output drops. Also, O2 sensors cycle when you're cruising - they're very sensitive around 14.7:1 AF ratio, and the ECU will constantly correct to keep it close to that, giving the cycling voltage. As they age, they get "lazier" in the cycling, you can actually feel it sometimes when cruising on the interstate as a "chug".

Anyhow, a multimeter can easily tell the health of the sensor. Check the shop manual for details.

I don't think a modified car would wear out O2 sensors faster. The only real "bad" thing you can do is run leaded race gas, which fouls one out rather quickly. Going to a heated oxygen sensor (from a mid-late 80's Ford Escort, for example) will let you run leaded race gas - the sensor will still foul, but it will take FAR longer to do so than an unheated (ie, stock) sensor.

Personally, I've never had any issues with any generic O2 sensors, and I've installed my fair share. I've heard of some having problems with the Bosch sensors, but it's hard to say. Definitely don't pay the money for the Mazda sensor - it's an absolute ripoff. Oxygensensors.com has a Walker O2 sensor with the OEM electrical connector installed for $60, BTW. A generic one is like $20, and you have to cut and splice the wiring, which is quite easy.

Dale

 

i just replaced my sensor recently .. got it off oxygensensors.com .. went with the denso .. good price .. cheaper than buying a bosch one at pep boys (about 110) ... plus the bosch ones that people say theyre having problems with is the one wire one .. which can run you about 20 bucks (you get what you pay for) .. anyways .. replaced my o2 sensor and car runs alot smoother .. i can notice the difference .. i dont know how old the previoius one is .. the previous owner probably never changed it .. and i can only assume it was as old as the car

 

my o2 was starting to fail with only 15-20K miles on it.

 

When you say "ECU will throw a code"... forgive me, but what do you mean? Lights will illuminate on the dashboard? I haven't touched my ecu, nor do I plan on it... I am just sticking with my 3 mods... I believe my o2 sensor is about 100k old...

 

It's hard to say. Mine failed but no ECU code, this was confirmed when I installed my PFC and the voltage on the O2 was bad. I did replace with Bosch for $80 and get good voltage now but our cars do put out more heat than most (turbos!) but it's up to you. I would say do it every other year before your smog inspection to get the best possible check but most of the time (driving) it really isn't even used. Only when, say, a steady speed for some time on the freeway. My PFC allows me to just turn it off all together (and I did for a while) and no noticeable change in driving to me?!

 

Mine failed and threw the code 17(?) and to answer the previous question the check engine light (or CEL) does illuminate, except for circumstances such as the post above mine.

I myself went with OEM as it was recommended to me by a friend that is a rotary mechanic. He said the universal ones just didn't last too long in comparison. I think I would have gone with the universal (one wire) one had I known that the oem cost so much.

 

I went with a Bosch universal which sold for $20 bc it was readily available whereas the OEM had to be ordered. I had to change it to pass the smog and the CEL never came on probly bc it wasn't totally wacked.

Changing it took 20 min as long as you can get the front on a jackstand or ramp.

 

Never had a problem with the Bosch universal myself. Works great and the best part is it's super cheap!

 

Pettit is now selling a heated sensor $140 or so & that is my next O2.

I installed a wide-band for monitoring and moved my stock sensor way down the pipe just in front of the cat. I suspect there is a reason why Mazda put it up close in the exhaust stream.

I thought it was getting hot enough but not so. A single wire sensor needs to get hot, something like 600 degrees, before it starts working. Mine only generates appropriate voltages intermitantly in the more distant position. At 2,500 RPM I get very little voltage at 3,500 in the approapiate range 250 to 800.

Can't go wrong with a heated sensor.

 

Most widebands need to be placed farther away than the stock location. Most recommend mounting right before the mid-pipe/cat, because they can get overheated and throw the readings off.

 

I did mine assbackwards. I put the heated wideband sensor in the stock location and put the unheated single-wire Mazda sensor just before the midpipe. I plan to correct that tomorrow.

 

if your muffler is red and ya smell gas--- you might be a red neck

 

jk i neeed a wide band 02

 

my frickin car smells like gas 94