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Full Version: Another High Idle Problem
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[Note to moderators: I started this as a new thread because the other idle problems I have read about are different than what I am experiencing. However, if you feel that it's similar enough to be added as part of an existing thread, feel free to move this there.]

A little over a week ago, I noticed that my CB1100 was idling high. It was a relatively cold day and I assumed that the outside temps had something to do with it. Instead of idling at around 1200rpm, it was idling at about 2300rpm at stoplights with clutch lever pulled in. Interestingly to me, the idle would drop to about 1800 when in neutral. I continued to ride it, hoping that riding at a higher speed for a longer period of time might help solve the problem. No luck. I text my friend, The Ferret and he relayed to me some of the advice from this forum (I was not in a position at the time to sit at a computer and search/read more on the topic. He suggested using the Kill Switch instead of the key. No luck. He suggested the "Open/Close Throttle" TPS reset technique. No luck. I rode it a few more times and noticed that the idle speed increased to 2800 and one other interesting thing: if I pulled the clutch lever all the way in the idle would drop to about 2000rpm, but if I let it out just a bit, but not into the friction zone, it would pop back up to 2800. I tried the TPS reset a couple of more times and sometimes it would idle at the more or less normal 1200rpm, but only until I'd engage the clutch at which time, it would increase to 2800 and stay there. The last thing I discovered is that the idle would not drop below 2800-3000 upon up-shifting or when rolling the throttle all the way off to slow down. This became disconcerting while making a turn at an intersection.

Took the bike to my dealer Tuesday. They determined that the ECU has failed. I don't know yet what other troubleshooting they did or possible solutions they may have implemented. All I know at this point is that they swapped the ECU from my bike with another 2013 that they happen to have at the shop and the idle problem stopped on my bike and immediately started on their bike. The service tech indicated that this is a "hardware" problem -- that there's a component within the ECU that is not working -- so re-flashing or other "software" solutions wouldn't help.


This is a pretty expensive repair (over $900) so I am going to have a few more questions for them about other possible solutions and about the price of repair for a customer that has bought 5 new bikes from them in 10 years, but I do trust these guys.

So, I am sidelined for a few more days while they repair my bike and fit it with new Pirelli Angel GTs. My 2020 goal of 183 riding days is on hold at 168 and my goal of 15,000 holds at 14,860. I'm going to use my riding time to finish off a couple of old Seat Time reports and maybe post a new one or two. Free time and dry pavement is a depressing combination for motorcycle-less rider.
I believe this is the first reported ECU failure. But, like any electrical/electronic device it can fail at any time. Sorry to hear yours did and I hope they will help with the price.
Any other failure indications? Check engine light on? Is the ECM unmodified (not reflashed?

I'd check junkyards and find an ECM from a wreck. They are very easy to replace; it's a matter of removing the fuel tank and unplugging the thing.
NO way I would pay a dealer over $900 for a new ECU

https://www.ebay.com/itm/13-Honda-CB1100...Sw2iNfRpo6
Sounds like a good diagnosis to me, likely one of the driver stages has failed and the iacv is not commanded close any more.
depending on your relationship with the dealer ( they did find the fault ) you may want to take a gamble on ebay;
https://www.ebay.com/itm/2014-12-16-Hond...2784175355

And then there is this option;
https://www.ecurepair.com.au/product/hon...c-611-ecu/
or;
https://www.fireblades.org/threads/fixin...cu.131046/
Just kidding but interesting to see what's inside an ecu.

And in the usa there's no hiss hassle either.

And/or have them install it for you, i don't think the quality of the ebay unit would be any worse than your unit, just something to consider for Christmas.
Yikes. Glad something repeatable was found.
Thanks all for the research on the ECU cost. I will take that up with Honda on Tuesday. The cost they quoted included labor, but I don’t recall the part/labor breakout. I’ll report back on that aspect of it.

Thanks, Max for your comments on the merits of their diagnosis. I will be anxious to see if my faulty ECU resembles the ones in your links.

LakeWylieJoe, no indicator lights and the ECU was unmodified.
The OEM list price for a 2013 is $643.49 and can be had for $482.62 from here: https://www.partsfish.com/oemparts/a/hon...re-harness

Item 10

Other suppliers may have it cheaper. IDK
Nicely done L.PG.
Wow Mi Lord, that's nearly 1/2 price depending on how much labor is

First ECU issue on this board that I recall. I was afraid it was going to be an IVAC issue.
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