Change O2 Sensors?

[brianl703]

Another place to try is http://www.oxygensensors.com -- they also have Denso sensors.

Although I replaced a Denso sensor in a 1997 Honda Civic Del Sol with a Walker sensor (purchased from above site)...worked fine.

(The Densor sensor's heater was open-circuited which is a failure I've never seen in any oxygen sensor before).

 

[Chris Meutsch]

I owned a 1989 Mazda MX-6 for 4 years and when sold with 164k on the clock, the original O2 sensors were still in place, still working fine. Just my experience

 

[Tosh]

Can suspect O2 sensors be tested in place? Will OBD2 and newer cars identify which O2 sensor is bad?
At ~$100 a piece, this doesn't seem like a preventive maintenance item to me (no matter what the Bosch ads say).

 

[brianl703]

You can test them with a digital multimeter that has a bargraph function. These are now often under $40, and if you get one with a frequency counter it's good for testing MAP/BARO sensors on Fords and MAF sensors on GMs.

Look for peak voltage and how fast it's switching with the engine running 2000RPM. It should switch (from low to high voltage) several times a second and the peak voltage should be about 700mV.

Of course oxygen sensors degrade in a linear fashion so as it ages the switch rate and peak voltage will drop, so determining when it should be considered bad is a bit of a judgement call, both for the person measuring the output of the DMM and the programmer who programs the ECU...

OBD2 cars will identify which sensor is bad.

So will some OBD1 cars, like all EEC-IV equipped Fords.

 

[Ramblin Fever]

Finally broke down and had to replace all 4 of mine on a 154k mile/9yr old vehicle. Code was being sent for 2, and started getting HORRIBLE gas mileage, so just bit the bullet and replaced all of them.

Glad I did, whole different truck, course there were other things that were done at the same time, but they did improve on the gas mileage and idling for sure.

 

[PandaBear]

OBDII uses a post cat sensor to see if the cat is dead, not for feedback of fuel injection. I wouldn't replace that if I am tight on cash, only replace it if it throw a code.

OEM and universal function very closely. However the fit/finish/quality may be different and you get what you pay for. I have to crimp my own connector using universal and it function just as well in my case. The heat shield isn't the same as OEM design and it gives me a little roar as I WOT. Other than that it works fine for me.

Heated O2S last longer because they don't need to be too close to the manifold and it runs cooler.

My new O2 gave me 0.5-1 mpg difference but my original HC, CO, and NOX are all high at 5mph, but fine on 25mph, barely passing smog. I knew it will fail next time so I change it out during holidays.

 

[ex_MGB]

On my '97 Max SE 5-speed I replaced O2 sensors at 110k when it threw a code. It sure felt like mid range torque felt stronger at wide open throttle in the 3k to 4.5k range. Others on maxima.org said the same thing.

Bear in mind I'm pretty anal on this car, keep fresh NGK coppers in it, fresh filters and regular throttle body cleanings. So if there was improvement, it wasn't masked by anything.

However, we're talking strickly butt dyno.

 

[brianl703]

I think it depends on the particular car..some have PCM programming that is better able to deal with O2 sensor malfunctions.