Highlander O2 sensors

Are some oxygen sensors better than others or do they all perform the same?

2003 Highlander here.
Reply to
franz fripplfrappl
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Yes, I'm in the ionosphere looking for a way to get back to earth.

Reply to
franz fripplfrappl

Yes, some oxygen sensors are better than others.

The answer to your second question is they all perform the same function but some are less durable and are more difficult to install because they don't fit as well or they require soldering or crimping wires. Since many people do not have good soldering skills or possess the proper crimping tools, the job is done poorly and they end up needing another O2 sensor in a short time. Some sensors are not as durable as OEM sensors.

Your best and easiest bet is to use OEM sensors.

I have some questions for you: Do you think you need an oxygen sensor? How do you know that you need an oxygen sensor?

You ask a lot of questions, which is one of the best ways to learn - keep it up! I'll try to coach you on how to ask the right questions that will get you useful information. :-)

Reply to
Ray O

No problem yet with 02 sensor. I am curious more than anything else. I believe the one(s) I have are originals. The vehicle is a 2003 Highlander with 55,000 miles. Also was wondering if replacing the unit with a better one would improve mileage.

Yes, I ask too many questions because I want to know. My friends have abandoned me because of my constant inquisitiveness. No one wants to hire me because I poke around too much. I bide my time waiting for Homeland Security to haul me away for questioning, but I'd probably have too many for them as well.

Thanks for our help and kindness.

Reply to
franz fripplfrappl

A new O2 sensor may or may not improve fuel economy, although the likelihood is that it will not improve fuel economy measurably. The O2 sensors for a particular application, like your 2003 Highlander, are supposed to be calibrated the same so when they are functioning properly, they should all theoretically provide the same fuel economy.

The purpose of the O2 sensor is to measure the amount of oxygen, or O2 in the exhaust gas. As O2 content goes up, the voltage of the signal it sends to the vehicle computer goes up, and based on the voltage of the signal the computer is getting, it knows how much O2 is in the gas. If there is too much O2, that means that the air/fuel mixture is too lean and so the computer sends a command to the fuel injectors to give a little more fuel. If there is too little O2, that means that the air/fuel mixture is too rich so the computer sends a command to the injectors to give shorter squirts of fuel. This too rich/too lean measurement happens a little over 60 times a minute and so the voltage signal from the O2 sensor looks kind of like a square wave pattern on an oscilloscope.

Over time, an O2 sensor can become coated with the same soot that coats the inside of your tailpipe, and the soot acts like a blanket or insulator, keeping the O2 from getting to the sensor. The sensor detects less O2 so it thinks the mixture is too rich and so the computer leans the air/fuel mixture a little more than it should. In theory, a lean mixture results in better fuel economy but in practice it doesn't always do so. By leaning the fuel mixture too much, the engine produces less power and so the driver depresses the throttle pedal further than normal, commanding more fuel, which reduces fuel economy.

If you are trying to improve fuel economy, try these tricks:

1) Combine as many short trips as possible into fewer long trips where the engine has a chance to warm up fully and take advantage of the emission controls.

2) Remove any unnecessary weight from the vehicle.

3) Inflate the tires by 5 PSI over the recommended cold tire inflation pressure on the door jamb.

3) As you are accelerating, back off of the gas pedal slightly 3, 5, or even

10 MPH before you reach your intended cruising speed and then very gradually accelerate the final bit to your cruising speed. This will allow the transmission to shift into overdrive sooner and lock up the torque converter.

4) Take your foot off of the gas pedal as soon as you see that you have to stop - the vehicle with a locked torque converter will coast a long ways, and try to avoid stepping on the brake pedal because stepping on the brake pedal unlocks the torque converter and of course, braking turns the momentum into heat, which doesn't help your fuel economy.

Of course, there are the basic tips that everyone should already know, like accelerating gradually uses less fuel than hard acceleration and keeping the car in good tune-up condition. Use OEM ignition parts for the best fuel economy.

Reply to
Ray O

Once again, thanks.

If the air intake has a higher percentage of oxygen, would gas burn more completely and would this improve mileage?

Reply to
franz fripplfrappl

You're very welcome!

The ideal ratio of air to fuel is 14.7:1 - 14.7 parts air to 1 part fuel.

Too much air (and oxygen) can raise combustion chamber temperatures, which increases Nox, or oxides of nitrogen, emissions. BTW, oxides of nitrogen is not the same thing as nitrous oxide.

Too little air and oxygen can increase hydrocarbon HC emissions.

Reply to
Ray O

Once again, thanks for explanation. It would seem possible to find the right "air" so gas would combust completely release the fewest harmful particulates.

Reply to
franz fripplfrappl

You are welcome!

As of now, the closest thing to the "right" air is to mix 14.7 parts to 1 part fuel.

Reply to
Ray O

There are many different types of "oxygen sensor". For example, wide- band, planar, the old thimble, etc.

See the following FAQ:

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Using NGK Iridiums (-IX or -Laser) can also help with the combustion process:

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Reply to
johngdole

Which one of those is "better?"

Reply to
aarcuda69062

You can't be serious...

Reply to
aarcuda69062

The various types of O2 sensors all work under the same principle. If the mixture is lean, voltage goes up, and if the mixture is rich, voltage goes down (not the opposite as I erroneously posted earlier in this thread as aaracuda pointed out). The different types of sensors, like thimble and planar, refer to their construction, not their function.

There are aftermarket "universal" sensors where you have to splice wires and there are aftermarket sensors with connectors that fit the factory harness.

Reply to
Ray O

Here's my "whirl."

The original poster asked; "Are some oxygen sensors better than others or do they all perform the same? "

johngdole replied; "There are many different types of "oxygen sensor". For example, wide- band, planar, the old thimble, etc."

To which I asked; "which one of those is "better.?"

What part of that don't you get Jeff?

Reply to
aarcuda69062

My silence means I have a life other than aat, unlike some others.

Reply to
aarcuda69062

That's the same thing you posted earlier, and it's still backwards. Lean = low voltage, rich = high voltage, been that way since 1978 as taught by Julie Sherwood at the Chrysler Training Center, 1979 new model introduction.

Reply to
aarcuda69062

Hope you've got some free time...

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Reply to
aarcuda69062

In a twist of irony, technically the front "oxygen" sensors in the OP's vehicle are A/F ratio sensors, which in fact do increase (scantool voltage PID) when lean, decrease when rich. That goes for the 4 or 6 cylinder. Why post more details when you can just wait for someone to give all possible permutations? :-)

Toyota MDT in MO

Reply to
Comboverfish

I was saving that for the 'money shot.'

ahh... The PID is a voltage display but is that actually what is happening ;-)?

Reply to
aarcuda69062

It doesn't matter?

Then it does matter.

Still doesn't answer MY question.

You didn't say that Ray would straighten _you_ out, you said that Ray would straighten _me_ out. No offense against ray, but he did pooch the voltages twice now, so I suspect ray won't be straightening me out on anything, ever.

"Some such line of shit?" It's right up towards the top, there's no need to invent things.

Reply to
aarcuda69062

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