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Author Topic: wideband O2 sensor q's  (Read 25861 times)
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Vishnuatepork
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« on: March 05, 2015, 09:44:59 PM »

Hello Guys! and Gals!, if theres any Gals here....

Motorcycle; Yamaha MT-01 (same engine as Yamaha Warrior)
with; power commander V and AT-300 (Auto tune)

A mate and I are trying to figure out just how effective the tuning is on the Dyno Jet Power Commander on my bike.
The Auto Tune, kind of tunes it self, using the O2 sensor....
but as we are slowly watching and learning, the O2 sensor(s) dont always seem to be 100%.  And if you continually accept the suggested trim values, it tends to a wee bit lean.  We think this is because of an old/miscalibrated/worn O2 sensor.


Bosch even put out a service bulletin stating that O2 sensors may have upto a 5% skew.
Bosch Y 258 K01 005-000e technical document.

So what Im trying to figure out, is,
1) Is there a better brand of wideband sensor - -what does everyone here use?
2) How do you measure your afr?
3) how much trust do you put in your O2 sensors accuracy?

Cheers
Alan

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suzuki vx800, 41mm FCR, shrink ported head, mega cycle cam, singh grooved head, custom headers, Supertapp exhaust, Ignitech ignition module, vs1400 drive hub, nology coils, magnecor wires, 12:1 cp pistons, carillo rods
JR529
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« Reply #1 on: March 06, 2015, 12:21:51 AM »

1) Is there a better brand of wideband sensor - -what does everyone here use?
2) How do you measure your afr?
3) how much trust do you put in your O2 sensors accuracy?
1) I use the same sensor, the Bosch LSU4.2, as well as the Bosch LSU4.9. Both read the same values for me but the 4.9 lights off a wee bit faster than the 4.2. That doesn't matter for me since they both light off far quicker than I need them. I have also tested the NGK L1H1 and the NGK LHA. They have a better reputation for longevity in leaded fuel but I have not experienced that in my case since I change the sensors out every couple of years, which is nothing on the longevity scale. The Bosch sensors seem to respond much faster to events than the NGKs do. 4.9 < 4.2 < LHA < L1H1.

2) I have 7 of them on the roadster, one in each cylinder and a single one in the downpipe after the turbo.

3) Trust, but verify. We pull the plugs after every pass and tune accordingly. The sensors are not a magic bullet. They measure oxygen in the exhaust and then make a logical jump to the AFR that would have resulted in that O2 concentration. But an exhaust leak or even a misfire will screw the reading up since both events will allow extra O2 to be present in the exhaust, and the O2 sensor thinks that means you were running leaner than you were.

Just my $0.02, YMMV   
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fordboy628
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« Reply #2 on: March 06, 2015, 06:55:49 AM »

1) Is there a better brand of wideband sensor - -what does everyone here use?
2) How do you measure your afr?
3) how much trust do you put in your O2 sensors accuracy?
1) I use the same sensor, the Bosch LSU4.2, as well as the Bosch LSU4.9. Both read the same values for me but the 4.9 lights off a wee bit faster than the 4.2. That doesn't matter for me since they both light off far quicker than I need them. I have also tested the NGK L1H1 and the NGK LHA. They have a better reputation for longevity in leaded fuel but I have not experienced that in my case since I change the sensors out every couple of years, which is nothing on the longevity scale. The Bosch sensors seem to respond much faster to events than the NGKs do. 4.9 < 4.2 < LHA < L1H1.

2) I have 7 of them on the roadster, one in each cylinder and a single one in the downpipe after the turbo.

3) Trust, but verify. We pull the plugs after every pass and tune accordingly. The sensors are not a magic bullet. They measure oxygen in the exhaust and then make a logical jump to the AFR that would have resulted in that O2 concentration. But an exhaust leak or even a misfire will screw the reading up since both events will allow extra O2 to be present in the exhaust, and the O2 sensor thinks that means you were running leaner than you were.

Just my $0.02, YMMV   

x2

Any irregularity in a sensor array/system causes the ecu to misinterpret the situation.

Always, always, always, pull and check your plugs.    That evaluation always works.     Now that they are affordable, get and use one of those small/tiny inspection cameras.   Insert it through the spark plug hole.    Get some practice in what your engine looks like undamaged.    When something looks "funny", bite the bullet and disassemble it to check.     BEFORE, it "disassembles" itself . . . . . .

I still have and use some Welch-Allen optical inspection tools.    I can't save the video like I can with the digital camera, but some of that stuff might be pretty cheap on E-bay.
 cheers
Fordboy
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RansomT
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« Reply #3 on: March 06, 2015, 01:37:53 PM »

1) As the Bosch sensors get lead contaminated they will read leaner and leaner, resulting in a richer tune (from actual).  As the lead contamination gets worse they become slower in response time.

2) I can't tell you how many bikes I've tuned after the owner purchased an AutoTune.  They end up taking them off their bikes and selling them.  I have my thoughts on why they get eronous readings, but I'm not sure why they end up tuning the bikes lean.
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Vishnuatepork
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« Reply #4 on: March 09, 2015, 12:31:20 AM »

1) As the Bosch sensors get lead contaminated they will read leaner and leaner, resulting in a richer tune (from actual).  As the lead contamination gets worse they become slower in response time.

2) I can't tell you how many bikes I've tuned after the owner purchased an AutoTune.  They end up taking them off their bikes and selling them.  I have my thoughts on why they get eronous readings, but I'm not sure why they end up tuning the bikes lean.

Ransom,
This bike is only running pump gas (for now)...  So what other sources of contamination are there? Im wondering if there any other ways to monitor the afr?  As I read more about the O2 sensors, I wonder why they havent been made more accurate, or why a better system isnt developed.

Id be very appreciative of your theories on why they tune lean.

Cheers
Alan
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JimL
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« Reply #5 on: March 09, 2015, 02:40:31 AM »

Do NOT turn on the heater circuit until you get leaned out and warmed up enough to reduce water droplets into vapor (in your header).  Cup position and cup hole arrangement is critical to prevent micro-cracking the heater element.  That level of testing is beyond the budget of almost all of us, so keep the heater off when you know its still too cool.

Listen carefully to the exhaust as you adjust that initial tune.  It gets quieter and softer tone as it starts getting leaned out.  Pay attention to components that vibrate with engine combustion frequency.  When things stop shaking, you are getting pretty lean.  If it is running pretty clean with these conditions observed, it is probably safe to turn on the heater circuit and start tuning.

Your best chance of water droplet damage is cool engine and lower rpm range.
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JR529
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« Reply #6 on: March 12, 2015, 10:52:25 AM »

So what other sources of contamination are there?

It's best to think of them just as you would a spark plug. Anything that will foul a spark plug will also contaminate an O2 sensor. Excessively rich mixtures and oil being the most common. Coolant will kill them quick so if you lose an engine the O2 sensor is gone as well. Lead will kill them but it takes a bit longer for it to do it as the effect is cumulative.

If you treat the sensor right they will last for ages, just like they do in a new street car. But if your engine is chewing through spark plugs then it is going to chew through O2 sensors just as fast.
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RansomT
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« Reply #7 on: March 12, 2015, 03:41:39 PM »

I believe that the charging system of most bikes (as well as crappy batteries) do not provide enough amperage for the WB02.  That paired with the where the O2s are mounted, usually too close to the exhaust tip (which puts it in the reversion area), all makes for erroneous readings.
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NathanStewart
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« Reply #8 on: March 12, 2015, 06:13:16 PM »

If a bike can power heated seats, heated grips and heated clothing then it can heat a single O2 sensor.
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« Reply #9 on: March 13, 2015, 05:21:34 AM »

If a bike can power heated seats, heated grips and heated clothing then it can heat a single O2 sensor.

If you look just at the voltage, at low rpms (say 3k) and compare it to 10k, you will find that it drops dramatically.  ?? None of my sport bikes have heated seats nor can I use heated clothing with those tiny batteries.  Maybe a big cruiser ....
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Stainless1
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Robert W. P. "Stainless" Steele Wichita, Kansas



« Reply #10 on: March 13, 2015, 08:50:46 AM »

Look at the wire sizes on any of the stand-alone O2 systems... that will tell you something about amp draw.  18 and 20 gauge are common. Yes, if you leave the system on overnight you will have a dead battery.... don't ask....
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Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.
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« Reply #11 on: April 16, 2015, 07:06:55 PM »

There are many reasons why these systems do not work properly. The biggest one is none of the aftermarket electronics follow what Bosch states in there tech sheets must be done. As for current draw a single channel system will surge to 6 + amps on start-up then drop to about a steady 3 - 3.5 amp draw when running. The units MUST be calibrated each time you go to use them and if your plan is to change altitude greater than 1000 ft you will need to shut it down and once cool, fire it back-up and recalibrate to get somewhat accurate readings.
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wobblywalrus
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« Reply #12 on: April 19, 2015, 11:23:00 PM »

Carbs solve all of these problems...
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Stainless1
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« Reply #13 on: April 20, 2015, 09:10:53 PM »

Wob, wide band O2 works with carbs just as well as EFI... gives you an idea of how your tune is doing.
 grin
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Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.
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« Reply #14 on: April 20, 2015, 11:58:00 PM »

A wideband sensor was used for three years on the Triumph at Bonneville with considerable dyno tuning done each year.  It was used for an air/fuel mixture gage.  Mildly leaded gas was used.  It worked OK the first year.  Halfway through the second year it gave me readings I knew were false.  It failed completely during the third year.  The bike has carbs so it is no big deal if the gage is not working.  Lesson learned is to set up a racing EFI system that does not use closed loop circuitry that depends on an oxygen sensor for input, on a motor running leaded gas.

The other Triumph has a Keihin EFI.  A racing map was loaded into it and the oxygen sensors were turned off by use of the software.  The system now ran in open loop mode at all times.  I took it over the highest mountain pass I could find and it worked OK.  The sensors providing input are the tach, the throttle position sensors, an air pressure sensor, a temperature sensor, and the manifold air pressure sensors.  The Keihin system does not have a air flow sensor.  All worked to trim the mixture so as to adapt it to varying environments.  Many folks with racing Triumphs do this.  The EFI mapping is done using the tuner's oxygen sensors.  The bikes are run in open loop mode with no oxygen sensors.

The EFI sytem I am working on for racing will be mapped for the motor on the dyno using the oxygen sensors and a Bazazz self tuning module in closed loop mode.  Then, the sensors will be removed before the leaded gas trashes them.  The system will be switched to open loop mode for racing.  I do not know if this will work, but it is what I am doing based on some advice by locals.       
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