1997 V6 O2 sensor replacement help:

[kenratboy]

Hi guys,

Need some help. I posted a while back about my fuel economy going south (to the tune of 20% less), and it was suggested I replace the oxygen sensor.

Well, I flip open my Hayes book and it appears there are three(!?) oxygen sensors in the car. OK. I then start searching on the Toyota parts sites and find a ton of sensors ranging from $30 to $200(!)

Where do I start? Do I just need to replace one of them? Do I need to replace all three? Be it replacing 1, 2, or 3, what part do I need to buy (not sure which one goes where in terms of what to order). Does it matter if my car is California smog or not?

Just not sure where to start (1, 2, or 3 of them), and which part is what and goes where. Any help is appreciated.

Thanks!

[toyomoho]

If you can, find someone with a code reader having real time output that can monitor the sensors as the engine runs.

The typically sensor to fail first is the first rear cylinder sensor.

The type of replacement sensor does depend if the car was built to California or Fed emissions standards.

Suggest using Toyota or Denso brand sensors and an OEM type not universal fit.

The AutoZone link below provides some info on these sensors.

http://www.autozone.com/addVehicleId...00c15280092684

[kenratboy]

Thanks. I think I am going to need to pay a visit to my mechanic. I trust him and I am sure he has some good advice. I don't want to throw $500 at the car and not have a noticeable improvement.

[ysun]

Originally Posted by kenratboy

Thanks. I think I am going to need to pay a visit to my mechanic. I trust him and I am sure he has some good advice. I don't want to throw $500 at the car and not have a noticeable improvement.

I got a lot of good suggestions from this forum and I replaced the B1S1 of my car with only $140(Denso Cali standard) by myself. On the back side of your hood, you can see your car is Cali standard or not, the Cali standard sensor is more expensive than the fed one.

[kenratboy]

Originally Posted by ysun

I got a lot of good suggestions from this forum and I replaced the B1S1 of my car with only $140(Denso Cali standard) by myself. On the back side of your hood, you can see your car is Cali standard or not, the Cali standard sensor is more expensive than the fed one.

Which one (physical location and part) is that?

Thanks!

[ysun]

Originally Posted by kenratboy

Which one (physical location and part) is that?

Thanks!

There are 3 sensors, B2S1 is the easiest one to be replaced, it locates at the front of the engine, you can see it directly when you open the hood; B1S1 is the hardest one to be replaced, it locates behind the engine, you can see it through the MAF side; B1S2 locates under the front passenger seat, it's easy to reach and to be replaced once you removing the font passenger seat first. To see which sensor is not functional, just drive your car to autozone or some garage to check the error code, it's free.

Non Cali standard sensor is Oxygen sensor, Cali standard sensor is Air Fuel sensor, they locates at the same places.

[kenratboy]

Thanks!!!

Of those three, is one more likely to fail? The issue is I am trying to improve my suffering fuel economy, and guess replacing these sensors is needed. Just don't know how many need to be changed.

There are no error codes, even hooked up of the tool (I have one), no codes are being thrown.

[ysun]

Originally Posted by kenratboy

Thanks!!!

Of those three, is one more likely to fail? The issue is I am trying to improve my suffering fuel economy, and guess replacing these sensors is needed. Just don't know how many need to be changed.

There are no error codes, even hooked up of the tool (I have one), no codes are being thrown.

I have no idea if there is possibility for a sensor to be 'half functional' or '10% functional' without the 'check engine' lighted on. Your question is beyond my limited experience.

Have you tried the Gumout Fuel Injector Cleaner?