It worked fine for about a month and then the CEL would come on as the thing would stop working for a bit, the light would go off, light would come back on a day later, etc. Really disappointing as you think Bosch is a quality part but not in this case. I went with an NTK 21002 picked up at the local AutoZone.
Looking at a ride log the sensor voltage does vary as expected, swinging regularly between about .2 and .8 volts. The track is not a nice regular sine wave, but more of a somewhat somewhat ragged saw tooth pattern.
That's how raw signal from O2 sensor should look like. ECM approximates that saw tooth and calculate average, but the ECMDroid shows raw signal from O2 sensor. If your sensor voltage would not jump like that it would be bad sensor, bad wiring or bad ECM.
Ideally you have to catch the log when that power cut happens, if it did not happen it is not useful data.
If you can also log throttle position sensor angle that might be helpful. If the TPS is bad it might show wrong angle and ECM might put wrong amount of fuel. Let's say you open your throttle pretty wide but bad TPS shows low angle for a second so ECM triggers the injectors for too small amount of time accordingly and as result the engine grabs a lot of air and very small amount of fuel mist, as result preignition happens, that small amount of fuel explodes before the piston passed the top position and it works like brake, plus there is no fuel anymore to push the cylinder down after it passed the top dead center. And this might be the power cut you feel.
The TPS might have only small portion where the resistive elements rubbed off or damaged so that's why it happens pretty rare.
Damaged TPS wires, or internal damage of ESM might cause wrong TPS reading too. But you should be able to see it on the log, just remember how wide you opened the throttle when power cut happened and then check this area on the log.
Also warm up your motorcycle and perform throttle body leakage test. If it leaks you must to fix it first before you will do any other tests and logs otherwise all the logs are useless. If it leaks you are likely 90% found the issue.
Yes, the regular signal from the O2 sensor seems to indicate that it is working, but when it is out of the circuit the bike runs fine. (I've not yet tried just unplugging the sensor and leaving Closed Loop enabled)
The TPS seems OK. Readings are good, log recordings show no unusual changes, and the problem occurs only at steady throttle. If the bike is hiccupping and I roll on, the problem clears. For a while. Also, a TPS problem would be there in Open Loop as well as Closed.
If I had an intake leak wouldn't AFV be corrected up? The issue would also be present when I'm in Open Loop too and it's not. AFV is currently set at 93.
I have had the problem occur while logging data. I've not been able to find anything to clue me in but it is possible that I am not looking at the correct data stream to see the fault. I have MegaLog Viewer set to display TPS, RPM, O2, AFV, Spark, and Speed. Speed is just there to help me to figure out where I was at that point in the file.
The worst condition will be at steady speed for several minutes, near 3k rpm, at least 45 mph. Definitely in 5th, but possibly in 4th too. ONLY when running in Closed Loop. Take the O2 sensor, and whatever else changes from Open to Closed, away and the bike runs fine.a
I am going to try setting the minimum AFV at 95 and enabling Closed Loop. It would seem to me that if I don't allow the AFV to drop and the problem stays away, then the issue is the AFV being pushed too low.
If the intake seals leak intermittently wouldn't AFV climb as a result? AFV never bumps up and the O2 trace never shows a lean period. Also, leaky seals would not only leak under Closed Loop running, would they? Or would leaks cause more problems under that condition which is currently covered up by running Open Loop?
Mark, does the afv change value from time to time? mine seemed to have stuck at the same value a good bit of time back and I sent a logged file to Gunter. He went over it and replied I had a lean spot in a rpm location. he changed some values but with me riding in the same throttle setting areas all the time, he changed the polygon area that the bike would be in closed loop at different rpm, load areas. after that , my afv would subtly change with weather changes. afv at 93 would indicate a lean area of the map. I know when I ride with guys and really run the bike the afv would be slightly different than when I would ride with my wife at slower speeds. the ecm would respond as to how bike was ridden. best wishes on sorting this out.
After nearly a full month of riding with the ECU set to stay in open loop no issues have popped up. If there were a component issue such as a problem with the fuel pump, ignition coil, vacuum leak, etc. it would have shown up by now. I've run the same map with two different ECUs and noted no difference. Fuel mileage is down about 5 mpg but the bike is definitely fun to ride.
I am going to re-enable open loop running and find out if the problem comes back. If so, I'll replace the O2 sensor.
Sounds like you have an issue with the map in the Learned Fuel Area when bike is warmed up so no added fuel from temp compensation and CL is on, 4th and 5th gear at that rpm/throttle position. Esp as it is pulling fuel there.
So what would be causing this to happen? When I load the map everything is OK for a bit, then as the system adapts performance gradually degrades until I disable closed loop or load the map again. I have tried a few different maps and the same pattern occurs with each.
The whole time I've been following along, I'm guessing O2 sensor also. I'm in the middle of changing my O2 sensor myself due to mysterious surges of power and ubrupt power loss I experienced most of last season. While I'm in there I'm going to put a new fan in also. My Uly has 26K miles on it.
The fan is making odd noises, plus I went and bought a new fan years ago knowing that is would need to be replaced eventually and wanted to have it before you couldn't buy em anymore. With the old fan out, I can source the same motor, fix it up, and have a good working spare on the shelf still. As long as I have all this taken apart, I'm going to use this new fan while I can.
New parts are not always good parts. I think you're on the right track. Last year I changed my O2 sensor but I was getting a code. I put in a new fan while I was there but I'm at 60,000 miles. The new sensor cured my problem. The fact the problem started after you changed a known good sensor makes your conclusion quite probable.
Total: "The fact the problem started after you changed a known good sensor makes your conclusion quite probable."
I'm with this guy ^^^
I have experienced a bad O2. Not intermittent, totally inop and it would do as you describe but way worse. I could ride hard, forcing open-loop, but any part-throttle cruise would go to crap immediately when it would change to Closed Loop.
I'm not much for just guessing at problems, but IMO it's worth a new O2 in this case.
I should be clearer. The current issue did not crop up immediately after changing the OE O2 sensor. I rode with the new sensor for about nine months before I started noticing a problem. Gradually, over another two or three months, the occasional "what just happened?" moments became more frequent. Never any codes though.
I know you said you checked the ecm, did you swap out a good known one? I had a similar issue that drove me to swap out many different components, I could not duplicate in a static condition no matter how much I tugged on the harness. Good luck, losing my mind at the moment.
(Message edited by bobbuell1961 on April 09, 2020)
Fortunately for me, disabling closed loop covers up the problem and the Uly is quite rideable. I have a few other projects to handle, so changing the O2 sensor is back burnered.
I did try another experiment. I loaded a new map, set the AFV to 95, and enabled closed loop operation. Three 11 mile commutes later and the Uly started to periodically run poorly. AFV was down to 90.2. Disabled closed loop and set AFV to 93 and the bike is fine again.
I'm not planning to go into the mountains any time soon, so the Uly is OK as is. I'm thinking about adding a barometric sensor. It will be easier than changing the O2 sensor.