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. :-)
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.
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
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
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
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.
There are many different types of "oxygen sensor". For example, wide-
band, planar, the old thimble, etc.
See the following FAQ:
Using NGK Iridiums (-IX or -Laser) can also help with the combustion
Here's my "whirl."
The original poster asked; "Are some oxygen sensors better than others
or do they all perform the
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?
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
"Some such line of shit?"
It's right up towards the top, there's no need to invent things.
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.
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
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
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