well guys, I've only recently came back to AZ since I had an exhaust leak and needed a jpipe. Started browsing threads again regarding maintenance and what not. Stumbled onto the mileage thread and noticed people were getting much higher mpg as me.

I've been averaging anywhere from 13-17 mpg for past 7 years. Always thought it was normal for an old v6 car. Someone mentioned try changing o2 sensors even if I have no codes popping up. Decided why not try it and ordered denso sensors.

Installed yesterday and wowww. My car drives completely different. Feels less sluggish and a bit more responsive on the throttle. I feel I don't need to gas it as much to accelerate. I'm now getting 25+ mpg mixed highway local. I'm so amazed by this. I suggest everyone change o2 if you're having bad mpg or car feels sluggish or if it's never been changed. It doesn't hurt to try. I only paid $188 for both upstream sensors!

 

OEM sensors?


what year is your car? how many miles etc?

 

They are denso sensors but from what I'm told Honda uses the same exact sensors but brands them as Honda.

I have a 2005 AT with 136k. I'm the second owner for the past 7+ years. I don't put much mileage on it these past few years. Mostly local city driving.

 

Denso are good, Bosch are bad for our cars .


That's pretty awesome though, thanks for the anecdote!

 

I can't take the credit! Thanks to other posters that suggested this, the real MVPs!

 

clean the maf sensor also

 

Can you share the part numbers for the O2 sensors? I've got the same vehicle with about the same mileage. Not having the same gas mileage issues as you, but might be worth a swap...

 

i put bosch spark plugs in my old accord and i got random misfires.. switch backed to denso and it was all good

 

Bought from rockauto

 

I am always amazed at how crappy Bosch plugs and O2 sensors seem to be when put in cars which didn't come with those parts from the factory. I mean, regardless of vehicle manufacturer, be it Acura/Honda, BMW, VW/Audi, Chrysler/Dodge, you name it, Bosch parts really screw the pooch when they're put in.

 

Good info man. Might consider this on my TL that's about to hit 100k

 

Rather than dump a couple hundred dollars for nothing, I'd first monitor the O2 circuit for proper feedback.
Now I realize one would need an OBDII reader, but they are inexpensive ($45) and can be utilized many times over the years.
So, if one has the reader, test first, and if one needs a reader, think about purchasing one before changing the sensors.

 

Here's the thing, monitoring the circuit won't do you any good because they "appear" to the scanners (and the OBD-II system in the car) to be fully operational. Only by changing them will you know for sure.

Personally I absolutely hate throwing parts at a problem, however, the lone exception I can think of is upstream O2 sensors.

 

Excellent PSA bud. I would only really try this if you are experiencing CEL, can't pass emissions, or like OP you have really bad mileage. Otherwise your o2 sensors are likely working fine. Or want to be the ultimate PM king.

 

You'll never be 100% certain that a sensor isn't functioning properly, but a scan tool will offer oscillations/voltage from the sensors, and even a mm will be able to check voltage fluctuations.

 

Has anyone else got the same results ?

 

Are you expecting OP's results were merely a fluke?

 

In addition to Honda and Acura sites, I am active on automotive sites ranging from Mazda to BMW to Chrysler, and on every forum you can find posts where lazy O2 sensors, sensors which weren't throwing any codes at all, were replaced and instantly the fuel economy improved significantly.

Short answer to your question; yes!

 

Could be, but I would assume that a great amount would be in the minds of the posters. If you look at all the forums, people that use Sea Foam will also indicate, the car idles better, has better acceleration, gets better gas mileage, etc.
Personally, I just don't believe when O2 sensors with no codes are changed, the car will see 25+ mpg mixed driving, an increase of over 8-12 mpg and have better acceleration. That's even better mpg than when the car was new.

 

I'm not sold on the better acceleration thing, especially at WOT. Why? Because the feedback from the O2 sensors is completely ignored when at WOT, so changing the sensors should have no affect. That said, all too often I've encountered a thread where a car was returning say 17 mpg on the highway when 24-25 would be normal for that same vehicle; changing the upstream O2 sensor(s) very often seems to do the trick.

Now, if someone is getting say 23 mpg in the same vehicle, changing the O2 sensors will be a waste of time.

 

I have a 2006 TL with 225,000 miles never changed out the sensors, will these work with my year and is it (2) of number 2345010?

Thank you/

 

Yes they should.

Also overall my car feels and drives like a completely different car. Even my wife agrees with me. I should've done this 7 years ago sigh.

 

Busy all day, but just wanted to reply. There's no way that the mileage would be affected that much, and if the sensor(s) was sluggish or failed, there would be a cel. In fact, I'd say the O2 sensors can be disconnected and operated without them connected as many do, and the car would run fine on the ecu backup program and see just about the same mileage. The sensors only are functional at idle to keep the 14.7:1, and maybe up to 4500 rpm or so.
Too old and lazy to disconnect the sensors and hook up the gauges to test the above.

 

If/when your mileage noticeably tanks with no CEL and no codes and nothing obviously wrong, you have basically two choices, pay for lots of gas or replace the upstream O2 sensors. You don't even have to mention I suggested it.

 

I take it this wont work with defoulers.

 

That would never happen as if there were a problem, I'd hook up the meter as I always do when needed, drive the car and check the live data to see where the problem might be. Never had it happen to any car I ever repaired, and naturally some had non working O2 sensors. In fact, one of my cars has a lazy O2 sensor and when driving the cel will light as the ecu sees no activity in the 15 second span, and guess what the mileage is, same as when working properly.

On one of the forums, many run with the sensors disconnected as the tune is easier, and the overwhelming majority state that there is no appreciable decrease in mileage and then you'll see that one will state idle erratic and poor mileage. Consensus, there is another problem other than non working O2 sensors to which I agree.

Guess you had better post again about the decrease in mileage when you have definitive results, maybe disconnect the sensors and give it a try. Even the OP had stated he's been driving 7 years with the same mileage and now sees double the mileage. See he has an '05 with 136k miles, but 7 years ago was 2010 so the car was relatively new at that time, 5 years old with probably under 100k miles and the fuel mileage hadn't changed since, and from what I see, that's just about the correct mileage when one lives in Brooklyn. Now it's 25+ mpg and that's not happening when driving in Brooklyn.

Maybe the poster can me the old sensors and I can give them a test?

 

I'm thinking you might not understand how the whole loop works; disconnecting the sensors will not mimic an O2 sensor generating incorrect feedback, and such an O2 sensor will also not generate a CEL or any OBD-II codes.

 

That's right, but as I stated before to which you disagreed, monitoring live data will reveal the functions or non functions of the O2 sensors as well as feedback from all other areas.

 

Will it? How will you know if the feedback is correct?

 

Let me see....If one is having a problem with a cell or the current topic, fuel mileage, etc, hook up the $2500 SnapOn machine and view all the live data. Everything can be see from values to temps.

We're speaking of O2 values which is not a problem to read, but one can't find everything through a reader. Years ago, the daughter's Maxima had a intermittent stalling problem, but everything perfect on the reader so checked the IACV resistance and it proved to be bad. Replaced valve and car fine for the next 8 years until she sold it in 2016.

On our RX7 turbo, had a boost problem and as this car is pre OBD, used a Mazda unit that plugged into the ecu to view all the readouts and once again it was fine, nothing out of range. Further inspection found the C clip on the dash-pot pushrod had fell off. Not easy to see as the rod is behind the turbo between the exhaust and engine.

Let's not go, how do I know the unit is reading correctly!