XB9SX - check engine light, power and dimming headlights + stall

Seems like I am back with another unusual problem, which is a bit sad! I must say I have definitely enjoyed my Buell quite a bit, putting a fair few kilometers on it last year, but recently this year I have begun to have some odd problems regarding electric power and the check engine light (which has so many codes that is quite the nest to dive in to). If anyone recognizes the problem and there is a previous post dealing with it in this forum here I will gladly read over that one in its entirety, but here goes.

After around 30 to 40 minutes of riding my XB9SX I have the check engine light pop up on the dash. It will usually pop on for just a few moments and then go away, but I have learned that this is the beginning of my problems after doing three test rides. After this, after a bit of time passing my headlight will begin to dim, up until the check engine light comes on once more. If I am rolling along there does not seem to be any loss of power in the engine, and I can sometimes get rid of it by revving and powering out of the little episode (or so I thought.) Today, in looking for more tests regarding this issue I was rounding a slow corner in town, and the lights dimmed once more, check engine light came on, and I felt the bike hang up for just a tiny moment, very nearly stalling. I gave it some more power and went through the corner, but knowing something was up I pulled into a nearby parking lot.
As soon as I came to a stop the engine hung up, and died, lights dimming and everything. The dash reset at the same time, all dials doing the start up wave dance twice over as the bike struggled to get power. The clock reset as well, so I know the machine fully lost power for a moment there. I wondered if it was a battery issue, since it certainly seemed like it, but I could start up and stop multiple times without the problem resurfacing at all, nothing happening there on idle either, other than the fan coming on (more on this later). I was able to limp back home with the check engine light only coming on once more briefly and not having anymore problems with about ten minutes of driving, save for the fan coming on once again... and then again, and again. It seemed as though the machine was running very hot and the fan was trying to keep up. So at first what I thought may have been some sort of electrical battery issue might instead be an overheating issue? I wondered if the fan was running so much that it was draining the battery or something like that, so that after enough time passed the power was running low (which would be a huge problem itself there, possibly bad battery in that case) but upon coming home I have tested the battery voltage and it is sitting at 12.8 which is certainly a healthy level. So now I turn to you guys, does this sound much like an overheating issue? The fuel tank was quite hot at the end of the ride, and the fan coming on suggests that it could be overheating, but I haven't really encountered any of the issues related to overheating that I have seen elsewhere in this forum - i.e. skip sparking (unless that corner hangup I noticed was a skip spark) unusual revs or other engine problems. My fuel level was okay, just over half, so I don't think it was fuel boiling in the tank and causing odd things related to that.

I changed the oil at the beginning of the year, it is using genuine Harley Davidson synthetic, levels all seem to check out when looking at the dipstick, and the oil is not fouled already.

Tracing things back, one of my last rides in the previous year had ended prematurely from my bike refusing to turn over. Turns out battery had died back then, so I got a new one for this year, so I am running on a brand new battery.
Things I have tested and checked - I have looked through the error logs on ECMdroid, and my first test ride had a logged code saying low battery voltage but that never came up again (which is what started my hunting of a power problem.) I have gone through a few electrical things, TPS reset, I have check all grounds on the machine to make sure they are set correctly. I have checked the battery connections too, all of that is fine. I changed the spark plugs, wondering if there was something odd there - just a direct swap of NGK Iridium plugs to another identical set. In terms of heating I did have thermal padding in between the seat and the engine, which I have just removed tonight if it is an overheating issue. I also have the right scoop installed for more airflow, and have the whole time.

Information on the bike - XB9SX 2008
-K&N Air Filter
-Bueltooth ECM
-Bueltooth SS Exhaust
-NGK Spark Plugs

If this is an overheating issue I am not sure why it is coming up in this exact way. I am not running in overly hot, stop and go scenarios, driving before the event is usually from 60-80km/h, so should enough air getting in there to cool things off, especially so including the right air scoop. I'm a little bit at a loss here. Once again, if this looks like a previous post just point me in that direction and I'll read it, looking to try anything to be fair. Thank you very much for any information provided. I will continue to find other things around and follow up if I can.

Thank you for all the info! It really helps. The fan coming on does NOT mean it is "overheating". In fact most custom fan settings (like on a aftermarket ECM) are set way to low IMO. All that does is overwork the battery, the fan and the charging system.

Lots of guesses, I assume you have access to ECMDroid? First, what code caused the CEL? You can check "live data" while running and I would suggest putting voltage, and temp up top to look for erratic readings. A faulty head temp sensor would do this.
The headlight dimming may just be a reaction to the additional load of the fan coming on. Can you hear the fan clearly through your helmet with that exhaust, while at speed? I can't, but is it coming on and turning off a long intervals (1-2 mins) or rapidly like a loose wire/ bad sensor signal? May be unrelated.

I would also check AFV. The stall may not have any relation to the fan or temp. Perhaps just the odd buell intake pop from being overcorrected lean. If you are running Open Loop, you're kinda screwed here as the ECM has been neutered not to self learn or self adjust.

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Originally Posted by Cooter

Thank you for all the info! It really helps. The fan coming on does NOT mean it is "overheating". In fact most custom fan settings (like on a aftermarket ECM) are set way to low IMO. All that does is overwork the battery, the fan and the charging system.

Lots of guesses, I assume you have access to ECMDroid? First, what code caused the CEL? You can check "live data" while running and I would suggest putting voltage, and temp up top to look for erratic readings. A faulty head temp sensor would do this.
The headlight dimming may just be a reaction to the additional load of the fan coming on. Can you hear the fan clearly through your helmet with that exhaust, while at speed? I can't, but is it coming on and turning off a long intervals (1-2 mins) or rapidly like a loose wire/ bad sensor signal? May be unrelated.

I would also check AFV. The stall may not have any relation to the fan or temp. Perhaps just the odd buell intake pop from being overcorrected lean. If you are running Open Loop, you're kinda screwed here as the ECM has been neutered not to self learn or self adjust.

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Follow up time! Thank you very much for your swift reply. I believe I have found the issue and I will elaborate below. If it isn't the solution then I may be back soon enough again looking for more solutions, but this may just be it.

So, let's start from the top today. I rolled out my machine to check over things once more and took a drive to a nearby hockey arena. I started up ECM droid and began logging information. Driving there is a small trip with a mix of long road stretches and streets, so a good short term mix. Travelling to the arena about 7 or 8 minutes into the trip I got the check engine light once more, no problems with stalling or anything odd this time, just noticed the light popped on and disappeared. I stopped at the arena and checked out ECMdroid, only to find that my log actually failed about 13 seconds into my trip - that's a bit strange! Went back home and let the bike sit for a while. I wondered about heating issues, and went over my ECM, before deciding to change my EEPROM to a richer fuel mapping that I have. Immediate results in terms of heating, obviously the bike runs cooler with the richer fuel mix, but I still had that light pop on in my second ride today. The ECM did make it much further in the logging though, about 113 seconds in so that was good, and all I needed actually...

It appears you are right about one thing - the fan is draining my battery substantially. Voltage fluctuates from 15 volts, all the way down to 10.8 volts and dropping in the log. The reason why the logs were failing I think is that the voltage gets so low that the buelltooth dongle loses power, losing my connection entirely. The reason the logs were able to last longer after changing the fuel mix is obviously that the fan was coming on less and not draining the battery quite as much. The check engine light is a low voltage warning, anything else related to stalling and weird stuff was likely due to heating problems. All in all - a combination of effects that I think may have been fixed by getting a different fuel map, and next - getting a proper battery! The battery I got was a replacement from my dead one last year, and was bought directly at the Harley Dealership using the battery exchange program. Seems as though I got a battery that just can't handle the drain over everything at once. If this doesn't fix it, it'll be on to the next solution, but for now this is a tentative solution? Maybe? We'll see! Attached below is a screenshot of everything in megalog viewer, which I got set up today as well.

In terms of the screencap, you can see just how bad the battery voltage was fluctuating once the fan came on. From being at a red light to throttling up and then running in to the fan issues nearly straight away. At the end of the graph you can even see when I am throttling down for a second red light, and the battery voltage is suspiciously dropping once more, I bet that as I was slowing down (and when the warning light came on) that the battery voltage dropped too much and the Buelltooth dongle lost power from it.

Attachment 15423

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Originally Posted by kaboom!

It appears you are right about one thing - the fan is draining my battery substantially. Voltage fluctuates from 15 volts, all the way down to 10.8 volts and dropping in the log. The reason why the logs were failing I think is that the voltage gets so low that the buelltooth dongle loses power, losing my connection entirely. The reason the logs were able to last longer after changing the fuel mix is obviously that the fan was coming on less and not draining the battery quite as much. The check engine light is a low voltage warning, anything else related to stalling and weird stuff was likely due to heating problems. All in all - a combination of effects that I think may have been fixed by getting a different fuel map, and next - getting a proper battery! The battery I got was a replacement from my dead one last year, and was bought directly at the Harley Dealership using the battery exchange program. Seems as though I got a battery that just can't handle the drain over everything at once. If this doesn't fix it, it'll be on to the next solution, but for now this is a tentative solution? Maybe? We'll see! Attached below is a screenshot of everything in megalog viewer, which I got set up today as well.

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This screams of a grounding issue.

Harley batterys are known for being pretty good, and a much better choice than buying one from Wal Mart or some other discount store...however there are bad batteries out there, so I would have it load tested as well (by a real battery shop-not a chain auto parts store). You need a battery with at least 220cca.

Sir: a bit less time dicking with the ECM and concentrating solely on your battery/charging system will resolve this. every H-D dealer in north america exclusively stocks DEKA house-branded batteries. yours is ETX-14 issue. your OEM battery was also DEKA. they're the finest AGM "shipped sealed" battery that money can buy. BOTH DEKA and YUASA produced right up the road from me. yuasa great...deka greater.

Your solutions and things to check:
1-your ECM grounding wire/wires. they control most all ECM-lead functions including fan activation. a compromised ground can and will affect cooling fan operation. SM shows you ECM grounding leads. both black in color. and think about installing my recommended "rear coil bracket to sub-frame tab" auxilary grounding wire.
2-stock fan fuse is 10A. if it NOT popping...then the fan is NOT drawing too many amps. leave it alone
3-your 2008 VR-to-harness twin plugs behind factory left side scoop. remove clips from scoop...remove 2 scoop to frame screws...remove scoop....split plugs...inspect and clean and lube and reinstall
4-check to see if the VR is grounding to the mounting bracket. if it IS...it settles down the VR providing a bit more consistent charging system and voltage control
5-your CEL is coinciding with seeing substantial voltage drop. probably NOT storing historicals or actives. check for same
6-check positive cable attachment at starter assembly....check for cracks at both neg and pos cable ends at battery....check main ground and aux ground at left frame rail. check for even slight signs of corrosion where frame rail spars attach to main frame. if this thing has seen corrosive atmospheres, then split the sections apart and thoroughly clean
7-fully charge battery with 6 amps for 1/2 hour max. NOT a tender
8-install simple volt gauge atop left switchgear cluster OR monitor voltage with your little droid thingy or whatever it is. look for wild voltage swings. 10.5 amps then rebounding to 15.8 amps. have them? VR destined for trash bin.
9-check for parasitic electrical draw. aging XB models now developing them at an alarming rate.

Really good help above^^^^. ECMDroid reads voltage at the ECM so it is seeing what you are seeing. A crappy connection or your voltage fluctuating that much is a clear sign of a VR going out. Running voltage should be 13.5-14.7... NEVER below 12.5.

Try to find an OE regulator, or https://ricksmotorsportelectrics.com, but for SURE stay away from e-Bay look alikes.

Hello all, I am following up with the solution that has seemed to work for me.

I checked some of the groundings as suggested, but as soon as you guys mentioned a bad voltage regulator I sort of agreed and figured I would just get one. Definitely an immediate difference. Voltage stays above 13.5 volts consistently (at the lowest) and reaches heights of 15 sometimes. Beforehand with the faulty VR it would dip below 9 and max out at 14 or so. Regardless, getting a new voltage regulator has absolutely seemed to work. In general the bike has never run better, and for that I am glad. So in the end we can blame the voltage regulator and call it a day I think. If any other weird issues crop up I'll make sure to post them here, but I wanted to make a "resolved" post here so people in the future actually have something to look at if they encounter a similar issue.

Thank you all for your fine suggestions and getting this sorted out. Good riding!

Thanks for posting the resolution:eagerness: Don't forget a good battery for insurance:)

Also look up the threads describing how to mount a voltage meter on your dash. I have an '09 XB9SX.
Fluctuations here can alert you of a dying voltage regulator. Wish I had paid attention to mine, before it left me on the side of the road.
At least it was the PCH along the California coast, so it was a pretty spot to pass the time.