My fuel injected 04 Ultra has had a problem for a couple of years I have yet to locate. I also had it to the local dealer, and they did not find the problem either. After running for awhile at cruising speed, when I stop the bike will idle down very low and probably die unless I baby the throttle and front brake at the same time. The bike is very intermittent in the slow idle. After it does it once, I may ride all day and it doesn't happen again that day, or it may happen again 5 minutes later. I bought the Daytona Sensors Twin Scan II engine monitoring sensor to try to isolate the problem. While connected, the bike stumbled only one time. Viewing the logged data, the rear fuel injector pulse width fell to near 0 at that point. The front injector did not, it had a peak and then leveled off. After I bumped the throttle, the rear injector leveled off too. Now my question, what is the Twin Scan II actually looking at to arrive at the Front and Rear Injector waveforms? Is the ECM, the injector, or some other sensor the top suspect? Any help will be appreciated.

04Ultra

 

I'd take a look at the TPS voltage and the IAC at hot idle (105* C). TPS voltage should be .35-.45 and IAC at hot idle should be 40-42.

 

The Twinscan II+ actually reads the BUS data from the ECM. It is reading the outputs to the different components. ToBeFrank is dead on. Look at what's causing the injector to go to 0.

 

This may be obvious, but you may want to check you battery cable connections and any ground connections. A poor ground or excess resistance in the cables can cause some strange drivability symptoms.