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2G PLX WBO2 accuracy?

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Ohmega

Probationary Member
26
2
Aug 31, 2016
Harrisburg, Pennsylvania
I just recently installed Link and got everything set up to where it runs and drives like stock. I'm wanting to start tuning fuel, but I don't trust the accuracy of my wideband.
I used the wideband sensor in my previous Honda del Sol that I stuck a turbo on then had it dyno tuned. Drove it for approximately a year and a half maybe.

Is there a way to check the health/reaction time? Or just basically compare the ACTUAL A/FR versus what the gauge is showing?

P.S. I will provide a log when I get home.
 
Is that wb by innovate? Not 100% sure on that model, but on my mtxl the instructions state that ground should be common with ecu so I wired my ground directly to battery. Pull the sensor and leave it in open air, it should read all the way lean. Then take a rag and soak it with gasoline, then cover the sensor with it. It should read all the way rich. That's a simple way of testing it.

EDIT: The ground to battery is for an accurate output signal to ecu.
 
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You can check that the WB sweeps from lean to rich, but I don't know of any easy way to determine how accurate the sensor is reading. You would need a bottle of gas that has a known AFR value.
 
The PLX system is very good and a lot of old school tuners prefer it. I am not up on the newest generation Bosch 4.9 sensor, but back when the Bosch 4.2 was the most common, PLX offered the ability to use either it or the faster and more accurate NTK sensor. Innovate, while more popular nowadays has to my knowledge never offered compatibility with that better NTK sensor.

Aside from using known oxygen concentrations to verify the sensor, another wideband sensor in the same exhaust stream can verify accuracy.
 
Not quite. The sensor is still an oxygen sensor. It doesn't care if gasoline is there or not, just oxygen. It will not read rich unless there is a deficiency of oxygen.

Take a look at this demonstration. He uses brake cleaner instead but I think it still should work w gasoline.

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I can check the WB reading against AFRest assuming that the values used to estimate AFR are accurate?

Is that wb by innovate? Not 100% sure on that model, but on my mtxl the instructions state that ground should be common with ecu so I wired my ground directly to battery. Pull the sensor and leave it in open air, it should read all the way lean. Then take a rag and soak it with gasoline, then cover the sensor with it. It should read all the way rich. That's a simple way of testing it.

EDIT: The ground to battery is for an accurate output signal to ecu.

I don't believe it is an Innovate product. And the sensor itself is soldered directly to the front o2 ecu pin, so it should be utilizing the stock o2 sensor ground. The box that connects the sensor to the gauge is getting power and ground from the cigarette lighter since I do not use it.

I do recall an installation guide instructing you to calibrate the sensor in open air before installation, which completely slipped my mind- I'll do that ASAP.


You can check that the WB sweeps from lean to rich, but I don't know of any easy way to determine how accurate the sensor is reading. You would need a bottle of gas that has a known AFR value.

During fuel cut for closed throttle deceleration it does read 20.0
 
So I have a close setup to what your currently running and I happen to have a plx -dm6 4th gen with a Bosh 4.9 sensor ...not sure if that is yours or not...but my gauge is a touch screen and I also have a built in volt meter as well as a health check and reaction time meter built in... you just have to tap the left of the gauge screen to access the differant modes...I also ran mine in my integra for about year and a half and I have had it in my dsm for another 6 months and my health comes up around 85% ...i forget my reaction time as not in car at moment but these sensors are made to handle quite a bit...let us know what model you have as well as may be helpful if you have a dm-6 gen 4 everything you want to know is built into gauge...or just replace your sensor since they're pretty cheap to for plx :thumb:
 
The box that connects the sensor to the gauge is getting power and ground from the cigarette lighter since I do not use it.

This ground is what I was referring to, but since it's not by innovate, that might not make a difference in what the ecu sees.
 
I can check the WB reading against AFRest assuming that the values used to estimate AFR are accurate?

Theoretically, yes. In reality, it would be a long shot. When I tune the car (or as I prefer to say, "calibrate" the tune), I'm actually doing the opposite. I'm tweaking the SD table to make the AFRest (what the computer thinks is happening) match the WBO2 reading (what is actually happening) with my trust being placed firmly that the WBO2 is correct. Now that being said, it's all relative. What if your WBO2 is actually reading one unit below the true afr? Well, you would still tune your car like anyone else, but the end result of your fuel/airflow tables may look a little different. Instead of targeting a 10:1 afr you may be targeting a 9:1 afr to make the car happy.

The easiest way I can think of to validate your WBO2's reading is putting your car on a dyno. They typically have WBO2's they place in the tailpipe that you could compare to. Expect a little bit of lag between the readings, but if they trend the same way and stabilize at roughly the same numbers, call it good.
 
So I have a close setup to what your currently running and I happen to have a plx -dm6 4th gen with a Bosh 4.9 sensor ...not sure if that is yours or not...but my gauge is a touch screen and I also have a built in volt meter as well as a health check and reaction time meter built in... you just have to tap the left of the gauge screen to access the differant modes...I also ran mine in my integra for about year and a half and I have had it in my dsm for another 6 months and my health comes up around 85% ...i forget my reaction time as not in car at moment but these sensors are made to handle quite a bit...let us know what model you have as well as may be helpful if you have a dm-6 gen 4 everything you want to know is built into gauge...or just replace your sensor since they're pretty cheap to for plx :thumb:

I have the gen 3 SM-AFR and dm-6, with the Bosh 4.9 sensor I believe. From my experience, the gauge has never displayed a number for the sensor health or reaction time. I might have to mess with it tonight or wait a little bit for it to figure out the health/reaction.
 
AFRatioEst
AFRatioEst provides an estimated A/F ratio based on reported airflow and commanded fuel (injector pulsewidth). This should NOT be used to performance tune your car. It should be used as a check that reported airflow and estimated fuel flow make sense. This display value depends on knowing a LOT about your setup. If you do not provide accurate information here, you will not get accurate results. Garbage in = garbage out.

Taken from https://www.ecmtuning.com/wiki/ecmlink101initialchecks
 
Take a look at this demonstration. He uses brake cleaner instead but I think it still should work w gasoline.

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I'm at work and can't watch the video at the moment, but yes it could work with gasoline. I should have worded better, I did not intend to portray your answer as wrong, just incomplete. The key is to displace the oxygen, which the brake cleaner does well. If you do it this way, just make sure the sensor's tip is sealed off from atmosphere as much as possible. It will consume the little remaining oxygen and the reading will sweep to rich eventually.
 
Well yours should still have the same health check up that mine has you have to look as differant models but these are no calibration needed setups and I only start car and bump the throttle a few times so it goes rich a few times then change the gauge to health monitor then the reaction monitor....have to give a shout out for the plx tho because I have mine recording in ecmlink and my numbers are almost dead on to the gauge and have had it tuned with a wideband in tailpipe as well and was within .1 thru three pulls on dyno...as long as you havent been daily-ing your car for 6 months running rich the entire time car is running your sensor is probably fine...if your confident in your tune it's as easy as running car with sensor in ...once your car is warm at idle you should be hovering around 14.7...or take for a ride should be around 14.7 out of boost and closer to 11-12 in boost on a t25... if so the sensor is working properly and trust worthy
 
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