Oxygen/Lambda sensor odd readings

[subzero]

I'm experiencing odd readings in one of the oxygen sensors, ride is a 2013 R1200R. I decided to run a O2 plot after having a hard time starting the bike and noticing higher fuel consumption. Besides that I haven't experienced any other symptom, once operating temp. is reached, it doesn't hesitate and seems to run fine. The only thing I can remember of doing lately, is adding some Like Moly injector and valve cleaner, like I have done few times before.

 

2 plots showing GS911 output with throttle of 2,500 rpm. Sensor 1 drops to near 0, then shows normal response on idle (right most section)

 

 

 

So far this is what I've tried

• Calibrated idle actuators
• Calibrated exhaust flap
• Verified throttle cams, move freely and seem to open/close at the same time  (using finger method)

 

From what I've seen in other threads, seems these fuel/air issues are tricky to diagnose. Before I start swapping parts, could anyone point in the right direction?

 

[Hati]

Those plots definitely make the sensor look like it's faulty. You could try and swap them around to prove the fault moving with the sensor. It's not unheard of for them to fail but not that common either.

 

 

[dirtrider]

7 hours ago, subzero said:

I'm experiencing odd readings in one of the oxygen sensors, ride is a 2013 R1200R. I decided to run a O2 plot after having a hard time starting the bike and noticing higher fuel consumption. Besides that I haven't experienced any other symptom, once operating temp. is reached, it doesn't hesitate and seems to run fine. The only thing I can remember of doing lately, is adding some Like Moly injector and valve cleaner, like I have done few times before.

 

2 plots showing GS911 output with throttle of 2,500 rpm. Sensor 1 drops to near 0, then shows normal response on idle (right most section)

 

 

 

So far this is what I've tried

• Calibrated idle actuators
• Calibrated exhaust flap
• Verified throttle cams, move freely and seem to open/close at the same time  (using finger method)

 

From what I've seen in other threads, seems these fuel/air issues are tricky to diagnose. Before I start swapping parts, could anyone point in the right direction?

 

Morning   subzero

 

Not enough info to tell exactly but it looks like possibly sensor #1 heater is taking longer to heat the sensor to operating temperature. 

 

Make sure the sensor pigtail is fully plugged in & that the terminals in the connectors are fully seated & making contact on both sides. 

 

As Hati said, swapping sensor sides might be a good starting place but just keep in mind that if the problem is a connection issue that might temporally mask it. 

 

So possibly a sensor heater issue, or sensor connection issue, or even a lazy sensor issue.  

 

I haven't seen it on the camhead (yet) but have seen a few hexheads that the sensor  connector (terminals) were not making  good contact, or the connector was not fully snapped together. 

 

That sensor issue shouldn't cause hard starting as the o2 sensor info is not used for cold starting. The o2 sensor info isn't used by the fueling computer until the sensors heat up & produce reliable data. 

[subzero]

On 11/14/2023 at 5:28 AM, dirtrider said:

Morning   subzero

 

Not enough info to tell exactly but it looks like possibly sensor #1 heater is taking longer to heat the sensor to operating temperature. 

 

Make sure the sensor pigtail is fully plugged in & that the terminals in the connectors are fully seated & making contact on both sides. 

 

As Hati said, swapping sensor sides might be a good starting place but just keep in mind that if the problem is a connection issue that might temporally mask it. 

 

So possibly a sensor heater issue, or sensor connection issue, or even a lazy sensor issue.  

 

I haven't seen it on the camhead (yet) but have seen a few hexheads that the sensor  connector (terminals) were not making  good contact, or the connector was not fully snapped together. 

 

That sensor issue shouldn't cause hard starting as the o2 sensor info is not used for cold starting. The o2 sensor info isn't used by the fueling computer until the sensors heat up & produce reliable data. 

Thanks for the quick reply!

I visually inspected both o2 sensors, pigtail and terminals look OK. I disconnected the right side and ran the o2 plot, it showed a constant 450 mV, I believe is the way the computer knows there isn't a sensor.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Then I reconnected it, but this time logged data in csv formatlog 2023-11-14.csv. Very interesting findings, as soon as the throttle opens 0.39% the lambda factor 1 goes to 1.25 meaning max fuel is added, however this is still not enough for the o2 sensor voltage to indicate rich. Meanwhile lambda factor 2 remains unchanged close to 1 meaning ideal mixture in the left cylinder.

Since the o2 sensor in cylinder 1 returns expected values while idling, seems to me it might be actually working and the root cause is elsewhere, probably throttle bodies calibration. Also I've read the TPS (potentiometer) is prone to failure and leads to similar symptoms.

 

Any thoughts?

[dirtrider]

21 minutes ago, subzero said:

Thanks for the quick reply!

I visually inspected both o2 sensors, pigtail and terminals look OK. I disconnected the right side and ran the o2 plot, it showed a constant 450 mV, I believe is the way the computer knows there isn't a sensor.

 

Then I reconnected it, but this time logged data in csv formatlog 2023-11-14.csv. Very interesting findings, as soon as the throttle opens 0.39% the lambda factor 1 goes to 1.25 meaning max fuel is added, however this is still not enough for the o2 sensor voltage to indicate rich. Meanwhile lambda factor 2 remains unchanged close to 1 meaning ideal mixture in the left cylinder.

Since the o2 sensor in cylinder 1 returns expected values while idling, seems to me it might be actually working and the root cause is elsewhere, probably throttle bodies calibration. Also I've read the TPS (potentiometer) is prone to failure and leads to similar symptoms.

 

Any thoughts?

Afternoon subzero

 

I wouldn't be the TPS as that would effect both sides equally. 

 

That .450 volt is just the nominal voltage the fueling computer puts across the o2 circuit so that shows when the o2 sensor is not reporting due to too cold, or inop. If you unplug an o2 sensor it should show .450 volts. 

 

This one is not easy to tell without making it do something different.  Obviously the fueling trim reflects the o2 voltage. I just can't tell if an o2 sensor error is driving the fueling trim or a fueling error is driving the o2 error. 

 

Does the engine run Ok at those 0 fuel trim points?

 

Probably my next move would be to swap the o2 sensors side to side then see if problem moves with the o2 swap or stays with the same side (indicating a fueling (or combustion) issue of some sort.

 

 

[subzero]

2 hours ago, dirtrider said:

Afternoon subzero

 

I wouldn't be the TPS as that would effect both sides equally. 

 

That .450 volt is just the nominal voltage the fueling computer puts across the o2 circuit so that shows when the o2 sensor is not reporting due to too cold, or inop. If you unplug an o2 sensor it should show .450 volts. 

 

This one is not easy to tell without making it do something different.  Obviously the fueling trim reflects the o2 voltage. I just can't tell if an o2 sensor error is driving the fueling trim or a fueling error is driving the o2 error. 

 

Does the engine run Ok at those 0 fuel trim points?

 

Probably my next move would be to swap the o2 sensors side to side then see if problem moves with the o2 swap or stays with the same side (indicating a fueling (or combustion) issue of some sort.

 

 

Good catch on those 0 fuel trim points that appeared during idling. I didn't really notice any unusual behavior.

This weekend I'll try the o2 sensors swap and report back. By any chance you know what size spanner do I need?

[dirtrider]

8 minutes ago, subzero said:

Good catch on those 0 fuel trim points that appeared during idling. I didn't really notice any unusual behavior.

This weekend I'll try the o2 sensors swap and report back. By any chance you know what size spanner do I need?

Evening subzero

 

The o2 sensor hex size is 7/8" (22mm).

[6speedTi]

1 hour ago, subzero said:

Good catch on those 0 fuel trim points that appeared during idling. I didn't really notice any unusual behavior.

This weekend I'll try the o2 sensors swap and report back. By any chance you know what size spanner do I need?

I just replaced both O2 sensors on my 2012RT. I used the sensor style sockets. I had to heat up the pipes and sensors to remove them. My sensors were installed since new. 2012 with 104,000 miles. I hope your sensors will remove much easier than mine.

This was the kit I bought on Amazon, $20.   

 

GOHAWKTEQ Automotive Oxygen Sensor Socket Removal Tool Wrench and Thread Chaser Set 5Pcs https://a.co/d/hiwfvkk

[dirtrider]

22 hours ago, subzero said:

Good catch on those 0 fuel trim points that appeared during idling. I didn't really notice any unusual behavior.

This weekend I'll try the o2 sensors swap and report back. By any chance you know what size spanner do I need?

Morning  subzero

 

On the o2 sensors, when you are done moving them around & are going to leave the o2 sensors in permanently,  first put a little high temperature anti-seize on the threads. If you don't put a little anti-seize on the threads then those sensors will be a real pain to remove in the future. 

 

When you swap the sensors side to side, if by chance the problem stays with the side & not with the sensor, then your next move is to probably monitor the o2 sensor heating circuit (at the sensor connector). If the sensor heating isn't working there usually isn't enough combustion heat at idle to keep the sensor responding quickly. The fueling computer will turn the o2 heating off under some conditions but it typically stays on at curb idle. 

 

If the heating circuit tests OK then next move is probably to swap the fuel injectors side to side to see if the problem moves with the injector.  The .csv data shows both o2 heaters being commanded ON by the fueling computer but that is just commanded ON, not actual, as there is no confirmation feedback in this simple system.

 

That .csv data trap only shows the end result not the cause so something is causing those zeros. Could be an intermittent open in the o2 harness, or sticky fuel injector pintle, or an intermittent open if the wiring somewhere, or even a problem (like bad driver) inside the fueling computer. 

 

I seldom if ever see a 0 in the o2 sensor output, it can get there but none ever do when things are working OK. 

[subzero]

I was not able to swap the o2 sensors, I'm missing an hex bit to first remove the engine guard that sits in the middle. However I checked for resistance in both sensors heating circuit, both came at 6.3 ohms, more later on.

 

Looking for clues, I removed both secondary plugs and first thing I noticed they were not very thigh, I believe torque spec. is 9ft-lb. They look fouled with carbon deposits, no more than 15k miles on the clock. I know these are not the standard, wanted to give them a try. I didn't remove the main plugs as the coil puller is nowhere to be found. I replaced them with the correct part number, used though but in mint condition.

 

Next I removed cylinder 1 injector, spray nozzles didn't look clogged.

 

 

Finally I reset all adaptations using GS911. Took it for a test ride, as expected the bike started rough for a short time (re-learning adaptations) then it ran just fine.

The surprise came when I hooked it and ran the o2 plot and now cylinder 2 sensor also becomes unresponsive when opening the throttle. See attached csv data log log 2023-11-19.csv, it catched my attention that lambda control factors don't change even when o2 is reading lean.

 

Besides replacing the plugs with a fresh set, any other ideas?. How to test coils for failures?

[Hati]

2 hours ago, subzero said:

How to test coils for failures?

 

Ohm meter. You should get both sides (low voltage, high voltage) register with a reading. Preferably close to the other coils(s). Any side with no reading is open circuit, in other words faulty. Check your plugs too for hairline cracks on the porcelain insulator. 

[dirtrider]

Quote

How to test coils for failures?

Morning subzero

 

That is very difficult on the BMW stick coils as the secondary side is isolated (doesn't have a connection back to the primary). You can't just use an ohmmeter on the coils as the secondary will not read anything that tells you if your coils are good or bad.

 

You can ohm out the primary side but that side seldom if ever fails.

 

But even if you could test the secondary side that probably wouldn't tell you what you need to know as the hexhead/camhead coils typically fail with internal arcing of the secondary spark to the internal RFI shield. THAT you can't measure or find with an external meter.

 

If it runs good then the coils are probably working.

 

You can also test for a spark across a test spark plug with the electrode gap opened up but this just basically tells you if it will produce a spark in open air at atmospheric pressure. It won't necessarily tell you if it will spark under compression with a fuel/air mixture surrounding it. 

 

One way to test the coils is to run the engine then disconnect the coil power connector then see if the engine RPM or the idle quality changes. Not perfect but it can shed some light. DO NOT just pull a coil off of a spark plug while running as that allows the coil to arc internally.

 

Otherwise the best way to test for a stick coil issue is to swap in a known good coil or better yet coils. 

 

On removing the upper coils from the plugs__ Personally I never use the factory coil removal tool or even an aftermarket metal one as that aggressively pops the coils loose so the power wire connector should be disconnected first (it is ever so easy to damage those connectors if not extremely careful with the connector disconnect)

 

If the coils are really stuck on the spark plugs then using the factory tool can (usually will) slip then break the removal ears on the coils.  

 

What I usually use on the upper coils is 2 flat blade screwdrivers & an old credit card cut in 3/4" wide strips, then the strips folded at 45°.

 

I put the folded credit card (or double layer of cardboard) on the edges of the coil pocket in the valve cover (using that as a fulcrum for the screwdrivers) then insert the screwdriver tips in the coil slots at an angle. Then GENTLY & SMOOTHLY pry the coils off of the spark plugs. If done correctly the coils slide off of the spark plugs slowly & very smoothly. I usually don't even disconnect the power wire from the coil. 

 

[dirtrider]

Morning subzero

 

I am not on a device with Excel right now so will look at your .CSV file later, so look back here later today for input on the .CSV. 

 

On your o2 sensors, one thing you can do is simply unplug both o2 sensors then do an adaptives re-set. THEN ride the motorcycle with the o2 sensors disconnected.  That will remove the closed loop fueling control so you can then see what the trapped data shows with fresh (base) adaptives & no o2 sensor input.

 

If you still have anomalies in your fueling control then it is probably caused by something other than the o2 sensors. 

 

On that spark plug shown above, oil on the lower plugs can be somewhat normal (especially the L/H side)  if the engine is just started in place & not ridden for quite a ways after a cold start.

 

I can't see a lot in the picture due to the oil soot but that electrode gap looks mighty large (what does the electrode gap measure?) 

[dirtrider]

Afternoon subzero

 

I looked at the .CSV, you only ran it for about 1 minute so that is probably too soon for the o2 sensors to heat & come on-line. 

 

I also didn't see the throttle open very far so either you didn't open it much or the TPS is not reporting correctly. 

 

Next run, try a couple of very quick wide open throttle openings just to verify the TPS is registering full travel.

 

If it is running OK while riding then the fuel injectors are working OK. 

[subzero]

21 hours ago, dirtrider said:

Afternoon subzero

 

I looked at the .CSV, you only ran it for about 1 minute so that is probably too soon for the o2 sensors to heat & come on-line. 

 

I also didn't see the throttle open very far so either you didn't open it much or the TPS is not reporting correctly. 

 

Next run, try a couple of very quick wide open throttle openings just to verify the TPS is registering full travel.

 

If it is running OK while riding then the fuel injectors are working OK. 

Morning, plug electrode gap is 0.8mm

About the TPS sensor, I checked for voltages, the connector is giving 5V reference and similar value to ground. I plotted the values, it starts at 0% (fully closed) and it goes to 98% (fully opened), I didn't notice any sudden changes, it goes smooth all the way. I'll register in the next data run.

I removed right side secondary coil and it idles rough, almost stalling with some explosions out of the tail pipe.

New plugs on the way.

[dirtrider]

4 minutes ago, subzero said:

Morning, plug electrode gap is 0.8mm

About the TPS sensor, I checked for voltages, the connector is giving 5V reference and similar value to ground. I plotted the values, it starts at 0% (fully closed) and it goes to 98% (fully opened), I didn't notice any sudden changes, it goes smooth all the way. I'll register in the next data run.

I removed right side secondary coil and it idles rough, almost stalling with some explosions out of the tail pipe.

New plugs on the way.

Morning   subzero

 

With the secondary plug deactivated was that side still firing?  (ie that side exhaust pipe hot?)

 

The idle will roughen up & become slightly lower with a lower spark plug deactivated but it should still fire on that side on the upper coil. 

[subzero]

2 hours ago, dirtrider said:

Morning   subzero

 

With the secondary plug deactivated was that side still firing?  (ie that side exhaust pipe hot?)

 

The idle will roughen up & become slightly lower with a lower spark plug deactivated but it should still fire on that side on the upper coil. 

mmmm.....not sure, I ran the secondary coil test with an already hot engine, I'll repeat it when I get back home. Should I try the secondary first and then the primary? On its own, would the secondary be able to sustain combustion?