CB1100 Idle speed instability problem

[SportsterDoc]

I have had the low idle issue twice on my 2013 with 50k miles. Both times were stop and go traffic with temps above 90*F.

Both times simply shutting off the kill switch, turning it back on, and re-starting the bike fixed it temporarily. The problem will creep up again after 10-15 minutes if traffic remained bad but stayed away if traffic started moving. I haven't had the problem again after the temps went below 90*F.

I have not had the high idle issue.

Heat can affect electronics.
If a heat related issue is suspected of an electronic device, but it is intermittent, it can oft be replicated using a hair dryer.

Does the FSM detail what actions the ECU takes under higher operating temperatures?...or if the EOT is signaling the ECU that it is hotter than it actually is.

Hi Dave, good to hear from you again.

A question; in general would you agree that the issue starts gradually at some point and then gets progressively worse?

Not trying to put words in your mouth , just thinking in one direction and one step at a time if that makes sense..

Cheers max

Hi Max. My issue started with the slow idle / stalling. However, it was never a bad as the video on this thread. I could always restart my bike after it stalled, and it would run fine at a higher RPM - it just didn't want to idle. This issue went away by itself, and then the high idle (1,500 rpm) started about two months later. This lasted about 1 - 2 months. After a WFO run in the desert (started at low RPM in 4th gear to make a pass with a passenger on back and ran through the gears while wide open, but never exceeding 6,000 RPM), the high RPM idle issue cured itself also, and has never returned. About 2,000 trouble-free miles later the low idle / stalling has returned. I can keep the bike from stalling by blipping the throttle - it runs fine as soon as the RPM is increased above about 3,000. This low RPM / stalling comes and goes at will now. I will put my bike away when the problem occurs, and start it up the next day and it will run perfectly. I believed that the high RPM issue was brought on by slow, stop & go riding, when the engine got hot. But I have seen no connection to the riding conditions or temperature for the low RPM / stalling. In my opinion, the fuel mixture is leaning out when the low RPM condition occurs. I can sense a different response when I blip the throttle when this condition is happening that sure reminds me of a cold starting condition with a carbureted bike. Do you think there is any connection to the level of oil in the bike and this problem? Is it possible that excess oil somehow causes the EOT sensor to send a bad signal to the ECM? Also, my bike experienced poor low speed running from the day I bought it, which was finally cured by the TPS reset (I am extremely sensitive to how my bike runs, and the dealer said it was running fine, but I felt an immediate improvement after the TPS reset.) My bike has never shown an error code. Thank you so much for digging into this - I just don't have the time, or experience to diagnose electrical problems on my own.

1. Is IAC clean?

2. Have connections to IAC and EOT been disconnected and reconnected to "wipe" the contacts to insure a good connection?

3. Plugs read?...burning clean?

4. Check for vacuum leak (from post 570: I had a failure to idle issue on my V7II, first experienced at 8,000 feet altitude, ~5 months in service and 6,000 miles. It required throttle to maintain idle, even after returning to 2,200 feet elevation. Cured by tightening band around rubber from single throttle body to intake manifold.) It was a quick restart when it died, also.

5. Connections to all other sensors (O2, IAT, CKP) disconnected and reconnected to "wipe" the contacts to insure a good connection? On the XLForum, 07 up Sportsters have solved several issues by cleaning the CKP connection, which is down low and exposed to road grime.

6. Sensor values compared to FSM values?