I rode my 2009 Buell XB 12 Scg with 32000 miles home and Check Engine Lamp started flashing when I rode it at 60 mph. It flashed for about 1 minute and then it disappeared. The flashing periods were not very regular. The flashes were quite inconsistent.
After I arrived home I checked the historical codes with ECM Droid and found there are no error codes.
According to the Electrical Diagnostics Manual "the check engine lamp will flash during operation to warn of potentially damaging temperature. While this condition is in effect, the ECM will reduce engine power to assist in cooling the engine to a safe operating temperature. The check engine lamp will flash until the engine has cooled to a safe operating temperature. This will not set a trouble code."
As I understand it starts skipping spark plugs. I did not feel power reduction though, but I usually do not crank throttle like crazy so I do not know the full power level I should expect from this engine.
Today was pretty hot day and I idled in slow traffic a lot prior hitting 60 mph at the highway. But it newer happened before even in hotter weather and longer idles at slow traffic. It also happened after I already rode it for at least 10 minutes at 30-60 mph at no so slow traffic.
What I also noticed is the fan worked more than usual and never stopped at traffic lights (the fan usually stops after riding at good speed for long distance after stopping at traffic light, so the engine temperature sensor sensed more heat than usual). After I arrived home the fan worked longer than usually too.
What is going on here? Was the engine really overheating? Only other causes I can think of the black/yellow wire between the Check Engine Lamp from the instrument cluster and the ECM can be shortened to the ground somewhere (the ECM connects the CEL circuit to the ground when it sends CEL signal so the scuffed wire can cause such behavior). But that might not appear just for 1 minute and disappeared so suddenly and may reappeared which had not happened. Shortened wire would also probably caused less pronounced CEL brightness and flashes (like blinking faster and with less brightness or with irregular brightness, but the flashes were not so frequent and were bright, and it does not looks like shortage to the ground). Or it can be faulty engine temperature sensor?
Have you experienced it and what was it?
I also tested the fan with ECM Droid today and the fan sound was not very consistent. So maybe the fan is also dyeing. But I replaces the fan motor just 2000 miles ago, how it can die so fast? Maybe speed based fan work kills the fan so fast? I disabled the speed based fan work today, will see how long it will work until it will be completely dead. But I do not think the fan work is somehow related to the engine overheating since I already rode at good speed for 10 minutes before the flashing CEL happened.
OK, here is the video. On the video the CEL starts flashing at 0:30 and stops at 2:00.
I reviewed the video and noticed it started flashing irregularly, then it flashed pretty regularly with consistent intervals which makes me think it is not shortage or bad relay but ECM generated signal which is engine overheating according to the Electrical Diagnostic Manual. Then at the end it it flashed irregularly again and then after stopping flashing completely it never flashed again for the next 15-20 minutes of ride before I had arrived to the home. The rest of the commute included slow traffic and traffic lights idles.
I recently found a scuffed wire in the harness caused the issues with the injector. I was not able to inspect the damage in the harness thoroughly because of it requires engine rotation and it is too much work, but if there are more than one scuffed wire they may have shortage and cause the injectors open or close not consistently due to intermittent shortages in the harness causing lean mixture and engine overheating?
Today after a ride I hooked my Buelltooth dongle with ECMDroid and checked the rear cylinder themperature while idling. The temperature raised pretty smooth before 220C and once the temperature reached 220C the fan started working and the temperature value immediately jumped over 250C and stated fluctuate between 250 and 260.
Now I'm thinking this is ECM issue in the temperature measurement circuit or logic. I had similar temperature behavior on my old ECM (I replaced ECM due to the old one was a suspect of being bad).
Posted on Saturday, September 03, 2022 - 12:28 am:
OK. Today I hooked my Buelltooth dongle with ECMDroid and logged my commute (I selected to log the engine temperature sensor data). During commute the Check Engine Lamp happened again! There is definitely something bad is gong on. When this CEL happened I twisted the throttle and the engine started braking so bad that it felt like the motorcycle can throw me over the bar. I reduced amount of throttle the the CEL disappeared.
At home I uploaded the log data file to my computed and opened it with EcmSpy program. In Logfile Analysis the program found a bunch of potential engine temperature errors and transmission errors.
The messages window of the EcmSpy shows a bunch of engine temperature value jumps all over the place
You can see it jumps withing 240-280 Celsius withing 10-20 seconds.
The interesting thing is the temperature value raises pretty smooth before the fans starts working, after 220 C(this is when the fan starts working) the temperature starts jumping.
I also opened the log file in MegaLogViewer. Here is the moment where the fan starts working. The temperature jumps from 216C to 249C
So it looks like the fan somehow interfere the engine temperature readings. Do you think ECM is bad? Or bad fan can somehow affect the ECM temperature readings (I feel like the fan is bad too because if it works changing RPM and sound and have a "dead" spot where it will not start without help)?
And do you know what is the transmission error? Is it something related to signal transmission from ECM to ECMDroid?
You also can see I drove 60 mph for extended period of time this evening and the weather was not hot, it was pretty cool, but for some reason the engine temperature kept rising and stayed extremely high withing 270-280 C and the fan kept working at 100% duty. How is that possible if the cool air blows at 60 mph for long time but the engine temperature is soo high?
Posted on Saturday, September 03, 2022 - 05:34 pm:
OK. Today I disconnected the plug #10 from ECM and shortened the pins #2 and #3 on the ground with a probe and found the fan works just the same as it does with connected ECM changing sound pitch. A also noticed the contact between the probe and the pin makes sparks when the fan changes sound pitch and RPM. But I held the probe pretty steady so those sparks make me think the fan has internal shortage which is reducing the fan resistance and causing the sparks between the probe and the ECM plug pin I probed (because of the contact area between the probe and the pin is small and if fan has zero resistance AKA shortage all that current goes through the pin to the probe tip which has pretty small contact area causing sparks. When fan has shortage it is basically like you connect the battery 12V positive lead to the ECM directly (to the ECM pins #2 or #3) without resistor. Now I'm wondering if current spikes on the fan can affect the ECM. It looks like the fan motor commutator and the brushed are worn and the electro-graphite from the brushed shorts the brushes or maybe shorts the commutator coils or the brushes are damaged and short the through commutator contacts. Brushed motors suck.
Posted on Wednesday, September 07, 2022 - 10:09 pm:
was curious if you have ever checked baseline with bike at ambient and not running? Once a year or so when playing with mine, i'll roll it out of garage and keep it in shade. laser thermometer the fuel tank in centigrade. log on to your spy , droid or whatever and see what your IAT and CLT are at ambient. My 0712x has always been within 6 degrees c of each other with these three values. doesnt mean anything once motor is lit as all values are dynamic from that point on. I have read that sensors can shift range as time goes on. I have looked at this as time goes on to check and keep in back of mind in case any funny stuff goes on. so far i havent had any troubles with bike like this. This really has nothing to do with fan motor crapping out but manual says for mine operating temp is 180 to 220. if youre seeing 240c , then your on the way for heat management to activate. just my thoughts as far as these sensors go.
OK, I might found the issue, or at least the part of the issue. As I assumed that was the bad fan caused the current draw spikes and affected the ECM temperature readings.
I checked the bike at ambient and not running, and the displayed temperature was accurate in the ECM Droid. I also checked the resistance between the harness plug (which goes to the ECM) cylinder temperature pin and the motorcycle ground the the resistance of cool engine at ambient temperature matched the temperature of the sensor displayed in the ECM according to the electrical service manual.
I also checked the main harness and and found no issues. I also checked if the cylinder temperature sensor is loose and the wire is scuffed but it was OK.
Then I ordered a new SPAL fan and tested both fans the old one and the new one on oscilloscope and found the old fan is definitely bad, even when it sounded OK the current draw on the oscilloscope showed it jumps all over the place while the new motor current draw was smooth and consistent. Again for me it looks like the commutator is badly worn and the brushes short while motor is running causing current draw spikes.
So I installed the new SPAL motor and commuted today on my motorcycle and logged the commute. No check engine lamp appeared and the temperature raised smooth without significant spikes. There was no significant temperature spike when the fan started working. The maximum engine temperature during the ride was significantly lower than with the old bad fan.
So for me it looks like the bad fan motor internal shortages on bad commutator and current draw spikes caused electrical issues in the ECM temperature reading circuit or logic.
Here are the log graphs:
After replacing the fan the EcmSpy message box detected no any temperature sensor errors and significantly less transmission errors (I believe significant amount of transmission errors were caused by the electromagnetic interference caused the bad shorting fan motor)
The message box in EcmSpy still shows a few potential temperature sensor errors, but those are just a few withing the long ride and the temperature spikes are significantly less (just a few degree Celsius maximum)
And the most important the Megalog Viewer shows almost no cylinder temperature sensor spikes, even when the fans starts working. The maximum temperature is also significantly less (233 C with good fan motor vs 285 C with bad fan motor)
I said I might found just the part of the issue because of I still feel like the engine runs hotter than usually and the fan works all the time even I ride at 60 mph for long time at cool weather which did not happen before the accident with the shortened front cylinder injector wire happened. So maybe this accident or the bad fan motor somehow damaged the ECM so now it runs the engine hotter or reads the temperature of the cylinder hotter than it is. But I need a new ECM to check this theory and IDS, Inc wants $800 for new ECM with stock map, WTF!?