Oxygen Sensors Improve Fuel Economy ?

[e2vincent]

Hi All:

In lieu of the rising price of the gasoline, I talked briefly to my mechanic regarding fuel economy. He told me that replacing the oxygen sensors will improves the mpg dramatically. Is that true ?

Also, how many sensor total do we have on a 93 LS400, 2 or 4 ?

Thanks in advance for you imformation,

V.

[sha4000]

Hi All:

In lieu of the rising price of the gasoline, I talked briefly to my mechanic regarding fuel economy. He told me that replacing the oxygen sensors will improves the mpg dramatically. Is that true ?

Also, how many sensor total do we have on a 93 LS400, 2 or 4 ?

Thanks in advance for you imformation,

V.

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it should be 4 two front ones before the catalytic converters on each side and two behind them

[monarch]

The two oxygen sensors ahead of the catalytic converter affect fuel economy. Generally they should be replaced every 75,000 - 150,000 miles to maintain optimum fuel economy depending if you are mostly a city vs. a highway driver. If you use aftermarket sensors then you could get less fuel economy savings and shorter sensor life.

Unfortunately the same mechanics who may talk you into replacing the oxygen sensors will also likely talk you into using lower quality aftermarket sensors since they can't buy genuine Toyota sensors any cheaper than you can and therefore can't make as much of a profit compared to aftermarket sensors.

I believe lexls.com has a tutorial for replacing the sensors.

[SRK]

As Monarch says, if you do decide to replace the pre-cat O2's, use the Toyota part. The engine management systems on these cars are very sensitive, and even Japanese made aftermarket sensors like NTK are not up to the task.

Saving $200 in gasoline to pay for the new O2's may take so long though that the they will be nearing the end of their service lives.

The O2's you have are probably working well, and to keep them healthy keep clean fuel in the car, tune the engine to prevent misfires, and give the engine a workout every now and then with a full throttle blast. The heat created scours the O2's and also cleans out the cats. Puttering around at low speeds and idling excessively will reduce the life of both.

[sha4000]

As Monarch says, if you do decide to replace the pre-cat O2's, use the Toyota part.  The engine management systems on these cars are very sensitive, and even Japanese made aftermarket sensors like NTK are not up to the task.

Saving $200 in gasoline to pay for the new O2's may take so long though that the they will be nearing the end of their service lives.

The O2's you have are probably working well, and to keep them healthy keep clean fuel in the car, tune the engine to prevent misfires, and give the engine a workout every now and then with a full throttle blast.  The heat created scours the O2's and also cleans out the cats.  Puttering around at low speeds and idling excessively will reduce the life of both.

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i coudnt have said it any better when you open up on the highway the heat burns the carbon that builds up in the exhaust system that can coat the o2 and shorten its life alot of city driving will shorten an o2 sensors lifespan

[wwest]

Why does anyone believe that Lexus doesn't purchase their oxygen sensors from the very same source you happen to buy from aftermarket.

Besides which the EPA would not allow a substandard "degraded" oxygen sensor to be marketed within the US.

And why would a "failed" oxygen sensor be more likely to result in a richer mixture rather than a lean one?

Just speaking as someone selling processors that run much of the ATE, automatic test equipment, used to test automotive sensor and control components involved in emissions control.

[gmantob]

Why does anyone believe that Lexus doesn't purchase their oxygen sensors from the very same source you happen to buy from aftermarket.

Besides which  the EPA would not allow a substandard "degraded" oxygen sensor to be marketed within the US.

And why would a "failed" oxygen sensor be more likely to result in a richer mixture rather than a lean one?

Just speaking as someone selling processors that run much of the ATE, automatic test equipment, used to test automotive sensor and control components involved in emissions control.

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i purchase aftermarket oxygen sensors my Ls400 is running great and the gas mileage is great

[akewlguy]

gmantob... What is great?

It seems my LEXUS is getting about 19 around town and then 23 on the highway.. She really loves the premium fuel!!

I figure it must cost about 200 bucks per fuel sensor so that is 800/(.05) = 16000 miles.. I just wonder if I got a mile more per gallon or .05 (5% 19 to 20MPG) is it worth the 800 bucks? Does that make sense?

Cheers to LEXUS!

[akewlguy]

http://www.lexls.com/tutorials/EFI/mainoxygensensor.html

I guess they are not 200 dollars per sensor...