| Author | Message | ||
     Pdg17838 |
I recently completed a great 2300 mile trip to British Columbia on my 08 Ulysses. The Uly ran very well with one minor issue which I would like to understand and resolve. The issue is a stumble/misfire that occurs when running at about 3000 rpm. 3000 rpm is a nice spot to run on the highway in 5th gear. I understand that early Fuel Injection systems are subject to a condition called lean surge. This may be what I am dealing with in the 08 Uly. It feels more like an electrical issue with one stumble in the engine and then it runs smoothly again. The bike has an IDS ECU and Drummer exhaust. The issue has been consistent for the last 3k miles. No better, no worse. I run ethanol free premium fuel whenever I can find it. Air cleaner is a cleanable model which I recently cleaned. I think the misfire issue is more frequent in wet conditions. The previous owner had the jets cleaned and replaced the rubber mounting "Y" connector for the throttle bodies. New plugs about 3k miles ago. The old plugs looked fine. The bike has 20k miles on it. Ideas for debugging appreciated. | ||
| Tpehak |
It can be anything. Bad fuel pump, bad crank position sensor, bad rectifier, bad electrical generator, clogged fuel pump filter, bad fuel pressure regulator, bad fuel delivery system seals, clogged injectors, bad O2, bad temperature sensor, air leak, bad throttle position sensor, contaminated air inlet, bad temperature sensor, bad plugs, bad plugs relay, bad grounds or bad electrical connections to any sensor or electrical device. Electrical manual should have troubleshooting diagrams for such issues. There is Buelltooth dongle you can use with Android device with ECMDroid application to see error codes, sensors readings, fuel to air ratios and corrections can give you clues what is going on. It also allows to set the fuel correction ratios to default values so after resetting those and starting the engine you can judge by the engine behavior what is going on. (Message edited by TPEHAK on October 04, 2024) | ||
| Pdg17838 |
Thanks for the reminder to check for codes via buelltooth. The last time I looked there were not any error codes. I believe the throttle position sensor is good based on the voltage reading that it showed after performing a tps. It is confusing that the issue only occurs at 3000 rpm. I am suspicious of the fuel pump, fuel pump filter but the fact that it runs smoothly at higher rpm is confusing if the issue is related to the fuel pump/filter Here is a chart I found which I think shows the stock control loop areas.  |
