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Are Wide Band O2 Sensors Affected By 100LL

The Bosch 4.9 and NTK sensors are quite different and can't be lumped together.

Bob Mills and some others have had usefully longer life from their NTKs than most of my customers using Bosch 4.2 or 4.9 with 100LL

The Bosch wideband sensor was never designed with leaded fuel in mind to my knowledge and Bosch itself says life will be much shorter when using it. With the NTK, lifespan looks to be superior so far when running 100LL and that's encouraging.

We'll be starting to test an NTK on a local aircraft here shortly and hope to do a video on that soon.

Ross, what kind of lifespan are you seeing with the Bosch O2 sensors in your application?
 
Ross, what kind of lifespan are you seeing with the Bosch O2 sensors in your application?

Mine is the local plane that will be testing the NTK sensor system Ross mentioned.

Prior Bosch 4.9 experiences:
- Generally, SDS system or not, the O2 sensor reliability seems to be more tied to the AFR (leaded fuel) environment it is being operated in, the lean side it likes, rich or over rich it don't like so much & won't last long.

- The sensor we had in Bill Beaton's supercharged IO-540 saw wide AFR swings, mostly on the rich side so his sensors were good for max 40 hrs, but that is notably extreme operations. In his calmer flying recently, the sensor is lasting much longer.

- While experimenting with my 6A (dual SDS 360), I got the Bosch 4.9 to go off line when I made the engine swing toward over rich in rapid change succession, I am able to reset it in flight so it flew on. With the fuel map now stabilized and with the same sensor, I now have 110 hrs out of it. It is now showing signs of giving out, but I can revive it by removing it and cleaning with a shot of aerosol brake cleaner and a blast of compressed air, again good for another 5 or so hrs. This plane has seen a fair amount of formation practice lately so it is subject to frequent AFR sweeps which I think, is also factoring into the O2 sensor longevity.

Ross & I are going to experiment next with the Ballenger AFR500 NTK sensor system, I will be installing it with a delay relay set to activate the sensor 25 seconds after engine start. As Ross said, we'll report back...
 
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Ross, Inks, others:

What are the indications of failure (or degraded operations) that you see? Wacky numbers?, failure codes or indications just going blank or dashes?

Have you ever seen indications that just start to creep off accurate readings? That's a failure mode that might cause damage in some regimes.

The experimenter in me is considering buying another new probe (might still have a spare I'll find when I finish unpacking too :rolleyes:), and swapping them to see how performance compares. Hard to replicate conditions sometimes, but might get close. Or perhaps do as Klaus did, and weld a bung in every exhaust pipe and test them all. :D

Cheers,
Bob
 
Ross, Inks, others:

What are the indications of failure (or degraded operations) that you see? Wacky numbers?, failure codes or indications just going blank or dashes?

Have you ever seen indications that just start to creep off accurate readings? That's a failure mode that might cause damage in some regimes.

Cheers,
Bob

I've seen all of the above but not all failures are from lead contamination, some are likely from thermal shock, cracking the substrate when they suddenly just don't read at all and never come back to life.
 
Thanks Ross,

In the degrading failures, have you seen any trends, such as they start to read high, or low, or is it random? Thx!

Bob

I've seen all of the above but not all failures are from lead contamination, some are likely from thermal shock, cracking the substrate when they suddenly just don't read at all and never come back to life.
 
Mine is the local plane that will be testing the NTK sensor system Ross mentioned.

Prior Bosch 4.9 experiences:
- Generally, SDS system or not, the O2 sensor reliability seems to be more tied to the AFR (leaded fuel) environment it is being operated in, the lean side it likes, rich or over rich it don't like so much & won't last long.

- The sensor we had in Bill Beaton's supercharged IO-540 saw wide AFR swings, mostly on the rich side so his sensors were good for max 40 hrs, but that is notably extreme operations. In his calmer flying recently, the sensor is lasting much longer.

- While experimenting with my 6A (dual SDS 360), I got the Bosch 4.9 to go off line when I made the engine swing toward over rich in rapid change succession, I am able to reset it in flight so it flew on. With the fuel map now stabilized and with the same sensor, I now have 110 hrs out of it. It is now showing signs of giving out, but I can revive it by removing it and cleaning with a shot of aerosol brake cleaner and a blast of compressed air, again good for another 5 or so hrs. This plane has seen a fair amount of formation practice lately so it is subject to frequent AFR sweeps which I think, is also factoring into the O2 sensor longevity.

Ross & I are going to experiment next with the Ballenger AFR500 NTK sensor system, I will be installing it with a delay relay set to activate the sensor 25 seconds after engine start. As Ross said, we'll report back...

Could this conceivably lead to an upgrade of the code on the existing SDS ECU to accommodate the NTK O2 sensor?
 
decalin

I have been using a LSU4.9 with my SDS system for about 40 hours. So far it still seems to be running well. Since my project is turbocharged and new, I have chosen to run it on the rich side during this intial testing with the new engine and new turbo.

I would be curious to hear from folks who have used Decalin additive and whether there is any real world examples of good, or not so good results.
 
I have an Eggenfellner H6 Subaru in my RV-7A, with an SDS ECU.

I bought the SDS controller and Plexus O2 sensor a number of years ago.
I modified the original exhaust - from baffles + 1 outlet to no baffles and 2 outlets - which allowed the engine to produce more power, so I had to modify the fuel mapping tables. The O2 sensor was key to doing that of course.

I run unleaded auto fuel the majority of the time, but when traveling I usually need to use 100LL. When I do, I always add Decalin.

I have 600 hours on the plane now, and have never had an issue with plugs or the O2 sensor. I do find the white lead oxide powder on them when I pull them soon after 100LL use. The inside of the exhaust pipes get a white coating as well. I've never had any sort of lead buildup due to the Decalin.

The owner of Decalin has (or at least had) a Subie powered plane as well, so he was on our Subie Yahoo group, which is how I found out about his product initially (about 10-11 years ago...)
 
AEM (30-4110) UEGO Air/Fuel Ratio Gauge

Bob, sorry for the delayed reply.

The above is the AEM system I bought on Amazon. Sensor is the Bosch 4.9. I was incorrect in my post saying it is a narrow band sensor when in fact it is a wide band...memory, second thing to go....

The instructions say to mount the sensor a minimum of 10 degrees above the horizontal and 18" from the exhaust port. I put mine at about 45 degrees.

Ok great thank you.

It would be nice to know if the 4.9 sensors last much longer than the 4.2 sensors; the NTK's are 4.2. It is interesting to note that the main difference between 4.2 and 4.9 sensors is 4.2 sensors use a reference air thru the connector. If the connector gets fouled, accuracy can be affected. 4.9 sensors eliminate the reference air.

Is also interesting to note Bosch recommends installation at the hottest point possible. https://www.omnitekcorp.com/images/LSU42data.pdf
 
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Notes below,

The slow failures usually seem to manifest themselves with leaner than actual readings. I've posted this one before but it's a worthwhile read: https://www.nzefi.com/bosch-lsu-wid...l-often-aftermarket-performance-applications/

Thanks Ross, i think I may buy a new sensor and do a little cruise leaning testing, just to see how the older sensor compares.

What does smoke oil do the the sensors?

Good article, thanks Ross.

Greg, I have smoke injectors about 14" upstream of the exits of both ex pipes (6 into 2). The O2 sensor is about 4" upstream of the smoke injector in the left pipe, which places it about 5-6" aft of where the #2, 4 and 6 pipes merge. My smoke system puts out a ton of smoke, and so far, I've seen no ill effects on the sensor, or wonky readings when putting out smoke. i have the AFR on at all times, including show practices and performances, flybys, etc. Just a data point to share.

From the article Ross linked above, I imagine smoke oil may indeed cause issues if the smoke injector was upstream of the O2 sensor, just as with oil from old 4-stroke or any 2-stroke engines, as described in the article. There always seems to be some residual oil after smoking, and the more you open the needle valve, the more un-flashed smoke oil residue there is. I think I'd be sure to have the smoke injectors downstream.

Cheers,
Bob
 
I have an Eggenfellner H6 Subaru in my RV-7A, with an SDS ECU.

I bought the SDS controller and Plexus O2 sensor a number of years ago.
I modified the original exhaust - from baffles + 1 outlet to no baffles and 2 outlets - which allowed the engine to produce more power, so I had to modify the fuel mapping tables. The O2 sensor was key to doing that of course.

I run unleaded auto fuel the majority of the time, but when traveling I usually need to use 100LL. When I do, I always add Decalin.

I have 600 hours on the plane now, and have never had an issue with plugs or the O2 sensor. I do find the white lead oxide powder on them when I pull them soon after 100LL use. The inside of the exhaust pipes get a white coating as well. I've never had any sort of lead buildup due to the Decalin.

The owner of Decalin has (or at least had) a Subie powered plane as well, so he was on our Subie Yahoo group, which is how I found out about his product initially (about 10-11 years ago...)

Congrats on the long success on your "alternative" powered ship. and thanks for sharing your results on using decalin. I know that is not 100% guarantee it is the perfect solution but it means a lot to me.
 
Ok great thank you.

It would be nice to know if the 4.9 sensors last much longer than the 4.2 sensors; the NTK's are 4.2. It is interesting to note that the main difference between 4.2 and 4.9 sensors is 4.2 sensors use a reference air thru the connector. If the connector gets fouled, accuracy can be affected. 4.9 sensors eliminate the reference air.

Is also interesting to note Bosch recommends installation at the hottest point possible. https://www.omnitekcorp.com/images/LSU42data.pdf

Well the AEM instructions with my gauge certainly don't correspond with the Bosch information. Considering that Bosch is looking for 850C at the probe, AEM's 18" down the pipe location will give much less than that. At least in my install. Since my EGT probe is 1.75" away from the port and reads typically around 730C I guess it must be even cooler at the sensor. Bosch also wants the probe vertical, not minimum 10* above horizontal. Bosch says for unleaded fuel while the AEM instructions just say life will be reduced if using leaded fuel. Interesting.

Can't offer a comparison between the sensor types as I have only used the 4.9. Over 400hrs in the past 3.5 years and still working ok, on 100LL only. Another thing the AEM instructions say is not to run the engine without power to the sensor. Mine comes on with the master. They say this gauge can only be used with the 4.9 sensor due to reference air coming through the connector. The gauge will not work and may be ruined if another sensor is used.
 
WB sensors are heated so the heater can raise the temp of the sensor but cannot not lower it. The 4.9 is designed to work from 600 to 780C.

None of these sensors were designed for leaded fuel. Bosch says they will work, but lifespan will be reduced according to the lead content of the fuel. Automotive leaded race gas generally has a lot more lead than 100LL.

From Sunoco's race fuel page: "The useful life of an oxygen sensor used with a leaded fuel is hard to predict, but one thing is certain: it will eventually fail. Many racers using a leaded fuel in an oxygen sensor application are able to use the sensor only for tuning purposes and then remove it. This ensures a much longer usable life for the sensor."

With the relatively low lead content of 100LL, we've seen at least 2 customers get 350 hours out of their 4.9 Bosch sensors which I think is really good. However most get less than 60.

I'll say that sometimes having instrumentation that you trust is giving correct information but is in fact not, can be worse than not having it at all. I've had many customers and dyno operators chase non-existent problems, believing the WB is displaying the correct AFR when it wasn't.

The engine will often tells you what it likes. If the AFR is reading lean and you richen but it runs rougher, the O2 is often bad.
 
WB sensors are heated so the heater can raise the temp of the sensor but cannot not lower it. The 4.9 is designed to work from 600 to 780C.

None of these sensors were designed for leaded fuel. Bosch says they will work, but lifespan will be reduced according to the lead content of the fuel. Automotive leaded race gas generally has a lot more lead than 100LL.

From Sunoco's race fuel page: "The useful life of an oxygen sensor used with a leaded fuel is hard to predict, but one thing is certain: it will eventually fail. Many racers using a leaded fuel in an oxygen sensor application are able to use the sensor only for tuning purposes and then remove it. This ensures a much longer usable life for the sensor."

With the relatively low lead content of 100LL, we've seen at least 2 customers get 350 hours out of their 4.9 Bosch sensors which I think is really good. However most get less than 60.

I'll say that sometimes having instrumentation that you trust is giving correct information but is in fact not, can be worse than not having it at all. I've had many customers and dyno operators chase non-existent problems, believing the WB is displaying the correct AFR when it wasn't.

The engine will often tells you what it likes. If the AFR is reading lean and you richen but it runs rougher, the O2 is often bad.

Thanks Ross. I appreciate the great info.

For my purposes (Carbed O-360) I don't require the AFR. I installed it as a recommended tuning tool when I was trying a TBI which turned out to be a PoS. I left the AFR in when I changed to the MS carb. The AFR reads the same now as it did when I first installed it. The actual reading is not critical to me. It sits at around 10 when rich at first start and I lean to around 14.8 on the ground. Indicates 10 again at full rich during the runup and on TO. I lean to 14-14.5 in cruise which gives me Peak or LOP indication on my Dynon. This has been consistent since installation. I am usually cruising at 60% power on the Dynon. I always end up with the mixture lever at the same place on the quadrant. No issue with the richening from my cruise setting and rough running as yet. I fully expect it will fail at some point but it has no big impact for me.
 
OK, for anyone interested in trying the A/F monitoring route, please read the whole thread and stop wondering about the longevity of the Bosch sensors. The key is to use the NGK sensors. If they will also fail, I sure don't know when - my system has several hundred hours on it and it still works exactly like the first hour. At this point I find the utility of tuning with A/F ratio monitoring is so worth it, even if there eventually is an interval where I will have to spring for another sensor.
 
NTK

Ralph and I finally managed to get flying with the new Ballanger/ NTK wideband setup. Seemed to work well and I'll be putting a video together on this soon.
 
Lambda sensor

Ralph and I finally managed to get flying with the new Ballanger/ NTK wideband setup. Seemed to work well and I'll be putting a video together on this soon.
Hi Ross, did you have a chance to pull this one together? Thinking about adding an AF sensor to my GRT EIS 4000 or EFIS Sport EX.
 
Yes Ross did, posted on YouTube Dec 9, labeled "RV6A Project Part 2". His video shows the Ballenger AFR display (big red numbers), as well it being displayed thru the SDS controller head. Later in the video he is showing and explaining the graphical data output of the flight, how the programmed map is affecting engine operating parameters. We also were able to identify a loose connection to the Air Temp sensor that was slightly affecting the fuel map calculations and resulting in variable AFR outputs.

The temp sensor connector has since been fixed and AFR is much steadier now.
 
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Yes Ross did, posted on YouTube Dec 9, labeled "RV6A Project Part 2". His video shows the Ballenger AFR display (big red numbers), as well it being displayed thru the SDS controller head. Later in the video he is showing and explaining the graphical data output of the flight, how the programmed map is affecting engine operating parameters. We also were able to identify a loose connection to the Air Temp sensor that was slightly affecting the fuel map calculations and resulting in variable AFR outputs.

The temp sensor connector has since been fixed and AFR is much steadier now.
Excellent - thanks. Interesting video. https://www.youtube.com/watch?v=j1fCzLW9qgY

Where did you install the sensor? What type of bung? Is the controller box mandatory?

The website seems to indicate that you should not use the sensor all the time, but I assume that it's a critical part of the SDS system.

Seems to me that this would be a really helpful thing to have to adjust mixture, but very few people are using one - is this just inertia, or is there a reason why most people don't use one? BTW, I will mainly be flying with unleaded fuel - perhaps the historical problem of lead damaging lambda sensors is why we don't use them in aviation.
 
Excellent - thanks. Interesting video. https://www.youtube.com/watch?v=j1fCzLW9qgY

Where did you install the sensor? What type of bung? Is the controller box mandatory?

Ballenger sells bungs, or just get one made up. Our exhaust systems are pretty short, try to mount it at least 12" from the tail pipe exit if you can.
The Ballenger module is the cpu for this package, it has wiring that can export the AFR output to another display unit like G3X, or SDS control head, or similar display.


The website seems to indicate that you should not use the sensor all the time, but I assume that it's a critical part of the SDS system.

Actually it is considered an accessory to the aviation SDS EM5 systems we use. In Open Loop operation, the AFR (O2 sensor) is handy to use in developing/programming your fuel map, but is not used in the SDS EM5 system to calculate fuel map injector pulses during it's operation, other engine parameters are used to calculate that.
Conversely, in the Closed Loop systems your car uses, its injection system does use O2 levels to dictate it's fuel mapping operations.


Seems to me that this would be a really helpful thing to have to adjust mixture, but very few people are using one - is this just inertia, or is there a reason why most people don't use one? BTW, I will mainly be flying with unleaded fuel - perhaps the historical problem of lead damaging lambda sensors is why we don't use them in aviation.

Just hasn't caught on in a big way in aviation for the reasons you just stated. We are hoping the NTK sensor will last longer in a 100LL invironment than other AFR display system sensors, we shall see...
 
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The bung I have is about 3/4” long. The Bosch 4.9 & NTK sensors are about 1” to the top of the thread so sensor extends into the pipe about 1/4” . You might enquire with the sensor pkg mfgr what they think for longest longevity ( they won’t like the 100LL thing though). Also my bung ended up oriented in about the 2 o’clock position in the pipe.
Yes, one sensor used, installed about 16” from end of tail pipe, just up steam of the slip joint would have been better though...
 
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The bung I have is about 3/4” long. The Bosch 4.9 & NTK sensors are about 1” to the top of the thread so sensor extends into the pipe about 1/4” . You might enquire with the sensor pkg mfgr what they think for longest longevity ( they won’t like the 100LL thing though). Also my bung ended up oriented in about the 2 o’clock position in the pipe.
Yes, one sensor used, installed about 16” from end of tail pipe, just up steam of the slip joint would have been better though...
Thanks Ralph. I've ordered the kit from Ballenger. I guess you want it up from the slip joint due to possible air contamination?
 
Yes, would think less chance of air contamination.

I'm also thinking of putting smoke in, definitely would be installed in the other tail pipe as I think it would be instant death for any O2 sensor....
 
O2 sensor update?

Reviving and old thread. Wondering if there is any new info on O2 sensors and life expectancy in a 100LL application.

I now have 660+ hrs in 6 years using the same Bosch 4.9 sensor which has not been touched since installed. It still reads the same, as when installed, at the cruising power and mixture settings I typically run. I have always run 100LL and lean on the ground and run LOP in the air.

I am building an 8. After watching a Mike Busch webinar on leaning using CHT and fuel flow when LOP I think I will install an AFR in my new ride which will probably be an IO-360 this time instead of the O-360 in my 7.

Thanks for any input!
 
Reviving and old thread. Wondering if there is any new info on O2 sensors and life expectancy in a 100LL application.

I now have 660+ hrs in 6 years using the same Bosch 4.9 sensor which has not been touched since installed. It still reads the same, as when installed, at the cruising power and mixture settings I typically run. I have always run 100LL and lean on the ground and run LOP in the air.

I am building an 8. After watching a Mike Busch webinar on leaning using CHT and fuel flow when LOP I think I will install an AFR in my new ride which will probably be an IO-360 this time instead of the O-360 in my 7.

Thanks for any input!

Where did you install the sensor? I lean on the ground and cruise lop and am lucky to get 10 hours before the sensor is fouled…
 
I went through 2 Bosch O2 sensors.
First one lasted about 10 hours. Not surprising as running rich during break-in.
Second one lasted maybe 20 hours...
It's 6 inches from the exhaust flange.
I have 80 hours total now so I do run LOP in cruise.
I might try another one this spring.
Maybe another brand ???

EDIT The bung is about 6 inches from the flange.
The EGT probes are about 2.5 inches from the flanges
 
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Where did you install the sensor? I lean on the ground and cruise lop and am lucky to get 10 hours before the sensor is fouled…

See post #48. I installed it as per the instructions for the gauge. I have an O-360 with the Vetterman crossover exhaust. The sensor is installed on the left side about 18" from the exhaust port on about a 45 degree angle from the top. The bung is the one that came with the kit. It is an "AEM (30-4110) UEGO Air/Fuel Ratio Gauge" and came with the Bosch 4.9 sensor. Just looking on Ama... now it seems that many spec a non-brand sensor which seems to fail quickly. It is wired to come on with the master. The AEM instructions are not the same as the Bosch sensor installation instructions, as I found out later, but so far so good. I also run leaned out at all times except for TO. Next time I have the cowl off I will confirm the dimensions.
 
See post #48. I installed it as per the instructions for the gauge. I have an O-360 with the Vetterman crossover exhaust. The sensor is installed on the left side about 18" from the exhaust port on about a 45 degree angle from the top. The bung is the one that came with the kit. It is an "AEM (30-4110) UEGO Air/Fuel Ratio Gauge" and came with the Bosch 4.9 sensor. Just looking on Ama... now it seems that many spec a non-brand sensor which seems to fail quickly. It is wired to come on with the master. The AEM instructions are not the same as the Bosch sensor installation instructions, as I found out later, but so far so good. I also run leaned out at all times except for TO. Next time I have the cowl off I will confirm the dimensions.

What AFR are you reading when running LOP at cruise?
 
What AFR are you reading when running LOP at cruise?

The readings bounce around a lot...I guess since it gets pulses from the 2 cyls. I have it set for gasoline and it will read around 14.5-7 ish. My Dynon will then be indicating LOP. If I lean it beyond and try to get the AFR reading in the 15's I will feel a noticeable drop in RPM and power from the engine, although it doesn't run rough. My normal cruise is 60% power (on the Dynon) around 2400rpm (FP prop), leaned to LOP (on the Dynon) which is bouncing the AFR around the 14.5 mark indicating about 147kts. I don't have any burning desire for more speed (I enjoy the flying!) but I do like the 6.7 USGPM average fuel burn I get (I keep a spreadsheet and fill up after each flight so I know this is an accurate number after 660 flight hours). The AFR reading has been like this since installation.
 
The readings bounce around a lot...I guess since it gets pulses from the 2 cyls. I have it set for gasoline and it will read around 14.5-7 ish. My Dynon will then be indicating LOP. If I lean it beyond and try to get the AFR reading in the 15's I will feel a noticeable drop in RPM and power from the engine, although it doesn't run rough. My normal cruise is 60% power (on the Dynon) around 2400rpm (FP prop), leaned to LOP (on the Dynon) which is bouncing the AFR around the 14.5 mark indicating about 147kts. I don't have any burning desire for more speed (I enjoy the flying!) but I do like the 6.7 USGPM average fuel burn I get (I keep a spreadsheet and fill up after each flight so I know this is an accurate number after 660 flight hours). The AFR reading has been like this since installation.

I am guessing your sensor is fouled. When the sensor gets fouled, the AFR will read around 14.7 +/- .2 all the time. When I replace my sensor, it generally reads around 11.5 -12.5 for takeoff (full rich). When I cruise LOP, it is around 15.5 -16.0 (LOP). I know that it is fouled when it just sits around 14.7 continuously...and it gets fouled fairly quick... I have also tried the name brand Bosch and a couple of knock offs. No real difference in the operation or how fast they foul. Only difference is the cost.

Might be something to check...
 
Yes

I am running 16:1 to 16.5:1 WOT, and add 3* spark advance. Smooth running and really cuts the fuel flow down if I pull back the prop to reduce RPM also.

That is similar to what I see when the sensor isn’t fouled. Once it is fouled, it bounces around 14.7 regardless of mixture…
 
I am guessing your sensor is fouled. When the sensor gets fouled, the AFR will read around 14.7 +/- .2 all the time. When I replace my sensor, it generally reads around 11.5 -12.5 for takeoff (full rich). When I cruise LOP, it is around 15.5 -16.0 (LOP). I know that it is fouled when it just sits around 14.7 continuously...and it gets fouled fairly quick... I have also tried the name brand Bosch and a couple of knock offs. No real difference in the operation or how fast they foul. Only difference is the cost.

Might be something to check...

The readings do change. Mine reads high 10s to 12ish when I first start and when I do the runup full rich. Can't say as I have ever paid attention to what it reads on TO/climbout (I will try and remember to check it next time I fly). I do the big mixture pull to my mark once I level off after departing the cct (we are limited to 2500' at our airport until cleared by terminal) after which I will fine tune for cruise. Not sure what to tell you. When I first started with this setup I did the conventional slow mixture pull to peak EGT and then beyond to LOP. The Dynon indicated peak and the AFR was around 14.5 ish at peak EGT. When I leaned further the Dynon showed LOP and the AFR was 14.7-15+ and always bouncing around. I initially installed it when I was running a TBI because they said it was the best way to tune the TBI. After I removed the TBI in favour of a 4-5 carb I left the AFR gauge in, so I don't rely on it for anything. I will take the sensor out next oil change and clean it to see if anything changes.
 
Same here.

As for Bob, mine also continously stays at the 14.5 - 14.7 mark.

Never thought about removing/cleaning.
I presume removing lead deposits?
How and with what product/solvent or mechanically?
Has it been done before?
Mine has a bunch of small holes on the end.
 
As for Bob, mine also continously stays at the 14.5 - 14.7 mark.

Never thought about removing/cleaning.
I presume removing lead deposits?
How and with what product/solvent or mechanically?
Has it been done before?
Mine has a bunch of small holes on the end.

Not sure about cleaning it; I ended up replacing it.
 
As others have mentioned, once the sensor is fouled you can't count on the reading. Do a normal LOP mixture sweep (slowly) and watch your EGT - it will peak at the stoichiometric mixture which is 14.7. "Full rich" for us is in the 11-12 range, and 50-LOP is in the mid-16's.

I get mixed lifespans from the Bosch sensors, I had one that lasted almost 150 hours and another that failed in 10, but the average seems to be about 50 hours of 100LL runtime. I burn mostly 93E10 but will pick up 100LL on the road when needed on a cross-country.

I don't make any attempt at cleaning them - just replacement. I keep a spare in the hangar, when it dies I change it out and order a new spare.
 
As for Bob, mine also continously stays at the 14.5 - 14.7 mark.

Never thought about removing/cleaning.
I presume removing lead deposits?
How and with what product/solvent or mechanically?
Has it been done before?
Mine has a bunch of small holes on the end.

Earlier in the thread someone mentioned cleaning by wire brushing off the lead and spraying with brake cleaner to get additional life. Never cleaned one so I don't know.

Today, after shovelling out the snow, I turned on my master to see what happened with the AFR reading. I didn't start the engine. The reading started at 14.7 and after a few seconds it started to climb. After about 15-20 seconds it reached 18 and then went three dashes across. Is this what you guys see happen? Not a flying day so I didn't get to check it in flight yet.
 
Earlier in the thread someone mentioned cleaning by wire brushing off the lead and spraying with brake cleaner to get additional life. Never cleaned one so I don't know.

Today, after shovelling out the snow, I turned on my master to see what happened with the AFR reading. I didn't start the engine. The reading started at 14.7 and after a few seconds it started to climb. After about 15-20 seconds it reached 18 and then went three dashes across. Is this what you guys see happen? Not a flying day so I didn't get to check it in flight yet.
Not a flying day??? ha ha ha
No flying these last days, that's for sure. Between the Artic -30°C and now the snow... sheesh.
I never took the time to observe what the AFR read while not starting the engine.
Will do next visit at the airport.
I still have my old O2 sensor, the one that stopped after roughly 10 hours.
I might try to clean it by scapping some wire in the small holes then rinse.
I won't hold my breath though on any positive results.
I have a feeling that tetraethyl lead deposits, cooked by high temps won't go away easily...???
 
Timer

After my automotive engineer son in law recommended not powering up the PLX system for 3 minutes after start installed a timer and performed longer but still only ~50 hrs. Ross at SDS says with LL fuels beating a dead horse, he's probably correct.
 
After my automotive engineer son in law recommended not powering up the PLX system for 3 minutes after start installed a timer and performed longer but still only ~50 hrs. Ross at SDS says with LL fuels beating a dead horse, he's probably correct.

Interesting....the instructions with my gauge said not to run the engine before powering the sensor which is why mine is wired to the master. What to do.....
 
Theory vs reality

Interesting....the instructions with my gauge said not to run the engine before powering the sensor which is why mine is wired to the master. What to do.....

The theory is when they are energized cold the condensate present damages them..........
 
yep

Which is moving like a herd of turtles.

So back to my original question....It would appear there has been no change in the status of O2 sensors for us 100LL users.

Pretty much. They don't last long and are considered consumables. I wish mine would go at least an oil change before fouling but I guess that's just not to be...
 
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