Another High Idle Problem

emptysea

Road warrior
Thread starter
[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.
 
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...Computer-Brain-Tested-Works-Oem-/362784175355

And then there is this option;
Honda CB1100 SF HISS (KEIHIN, 38770-MCC-611) ECU - Vectriq ECU Repair
or;
Fixing a CBR 929 ECU
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.
 
Thread starter
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.
 
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.
 
Matt, without questioning anyone's opinion and diagnosis, you may reset ECU residual values and see what happens: nothing/not fixed, temporary short or long fix, permanent fix. Takes 15 min to do the entire operation at no cost.
I perform this "fix" on cars from time to time prior replacing ECU, and sometimes it helps/works. I am not a Honda tech, different brand.
Did Honda tech has a "hardware error" written/displayed on their device?, just curiosity.
Up to you and good luck with your repair.
 
Peterbaron:

I always enjoy reading your posts regarding our bikes! Delivered in such an articulate and engaging manner.

I found the ECU for US $442 on Hondabikes.com. That site is owned by my very enterprising local dealer/friend who had the foresight to register the domain name before Honda Corporate even thought about it. In tiny little Olympia, Wa. My advantage is being able to pick up the parts at the store and avoid shipping.

Anyway, I noticed that the part number for the ECU indicates that is has been changed from the stock 2013.

My 2013 continues to live its’ charmed existence. Never an issue of any kind.

Knock on wood ...
 
Thread starter
peterbaron_imp said:
Matt, without questioning anyone's opinion and diagnosis, you may reset ECU residual values and see what happens: nothing/not fixed, temporary short or long fix, permanent fix. Takes 15 min to do the entire operation at no cost.
I perform this "fix" on cars from time to time prior replacing ECU, and sometimes it helps/works. I am not a Honda tech, different brand.
Did Honda tech has a "hardware error" written/displayed on their device?, just curiosity.
Up to you and good luck with your repair.
“Hardware error” was my term not the tech’s. I’ll ask about resetting the residual values. Thanks for the advice.
 
Thread starter
My bike is already taken to someone — it’s in the shop now, presumably with the old ECU removed. Also, I don’t know how to perform the reset that you describe. I have no doubt that it’s within my abilities, but my comment about asking the tech to do this was because I have neither the instructions nor the bike in my possession at this time.
 
EmptySea_imp said:
My bike is already taken to someone — it’s in the shop now, presumably with the old ECU removed. Also, I don’t know how to perform the reset that you describe. I have no doubt that it’s within my abilities, but my comment about asking the tech to do this was because I have neither the instructions nor the bike in my possession at this time.
You can do it, it's DIY without any special tool:
* If possible warm up the bike to get normal operating temp and idling (not necessary)
* Ignition OFF/key out from the ignition switch
* Disconnect both battery cables from the battery terminals, the negative cable first.
* Cover both battery terminals with a plastic bag/rag to prevent accidental cable to terminal reattachment.
* Join both cables (- &+) together for about 10 minutes. If the battery cables are too short, jumper wire can be used.
* Reconnect both cables back to the battery terminals, the positive cable first, then the negative.
* Ignition ON, wait until meters sweeping is completed 2-3 sec, start your bike and observe idling......
 
Thread starter
Thanks. That does seem simple, PB. I will call first thing tomorrow to see if they can try that at the shop. As I said, I don't have the bike in my possession to do it and I'm not having it put together with the old ECU, riding it home (or having it delivered home) and then trying this. That would mean another day at least of not being able to ride. Since the bike has to be there for new tires anyhow, I think they should be able to try your reset technique (assuming they haven't already) pretty easily and at no additional charge.
 
Do not assume this is a common fix or solution but sometimes it helps due to an unexplained electronic glitch...
Technically speaking, if one wants to swap two identical ECMs between bikes/cars, the residual values should be reset.
For the cars I work on, I use a tablet with a special program that reads service data & communicates +++more with the ECM...but sometimes as a last resort before ECM replacement, I use this manual reset as described above.
:beerchug:
 
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