idle problem update

[1973cb750]

I have been researching this for a while and I finally have proof that honda knows about the issue. Their fix is the new ecu with updated superseded part numbers for the 13 and 14.   the old a23, new is a24 2013 and the 2014 is a a42 original and a43 updated, I have suspected for a while the issue was the firmware inside the ecu for the idle instability this was a conversation with a unnamed friend that wants me to flash his ecu that works for a dealer here is inside info of the updated ecu's     i have noticed on the 2014 about 10-20% of the bikes have the idle issue honda gave the ecu more control over the iac valve were as the old ecu has a set limit for th iac steps 

 

[pdedse]

Interesting.  At the time of my '14 standard going through the high/low idle, little by little it became apparent that Honda Europe had this figured out and some owners there had their issue fixed because dealerships had mapping that would fix the high/low idle.  But Honda America wouldn't do the same.  I called / wrote Honda customer service and even spoke of this to which the person(s) claimed having no knowledge of what was done in Europe.  Maybe that was true, maybe not.  But they were open to the idea of "seeing what the dealer said" and didn't come right out and say "no" to possibly covering the expense even though the bike was 6 months out of warranty. 

Because of the intermittent nature of the problem, the dealership service manager warned me that diagnosing such a problem--in his experience--often meant several hours, 5-8 in some cases he had experienced ... of bill-able time.  Their hourly charge was $125.  I had never come across an issue like this with any vehicle and wasn't sure what to do.  But the bike needed new tires badly, was due for an oil change, brake/clutch fluids, the battery may have just started showing signs of needing replacement.

I started looking at the Triumph Street Twin, and a local dealership had a previous year left-over heavily discounted, and they offered $4600 on trade-in for the CB1100.  Faced with taking the bike across town an hour away and dealing with a who-knows-how-long-a mess, I bailed.  I only paid $7k out the door for it and I wouldn't have felt comfortable selling it to someone, so it didn't seem like a terrible move. 

Alas, the Street Twin, while very fun to ride, seemed too small after the CB1100.  The new '17s had already been out a year, and I bought my EX early in 2018, figuring lightening wouldn't strike the same owner twice.  Some time later I read of the part number change you refer to, and figured they had it sorted oui.

Have there been any cases of '17+ models having the high/low idle issue?  To my knowledge...no.

 

[1973cb750]

no the 17 models have a ecu with 2x the amount of data in them i have flashed two 17 models they are a different animal ecu wise same motor though definitely smoother because of all the extra data points in the ecu

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honda refuses to admit the issue hear but in their parts system it shows a issue

 

[Nachodaddy]

My 2013 standard had an idle problem which I documented thoroughly on the old forum. I wasted a lot of money getting a new IAC before replacing the ECU. A forum member in South Korea had the problem and his Honda dealer fixed it by replacing his ECU, so I tried it. The first thing I noticed was that the part listed on Partzilla had a different part number than the one on my bike, but it worked. I think Honda found a flaw in the old ECU and quietly replaced it. My bike ran flawlessly with the new ECU. I would have a lot more respect for Honda if they had admitted that ECU was bad and offered a free replacement. It was a very good bike that had it's reputation spoiled by that problem.

 

[1973cb750]

yeah they should have issued a recall i believe instead of passing on a purchase of a 700$ ecu plus labor at a dealer for most

 

[pdedse]

...I think Honda found a flaw in the old ECU and quietly replaced it. My bike ran flawlessly with the new ECU. I would have a lot more respect for Honda if they had admitted that ECU was bad and offered a free replacement. It was a very good bike that had it's reputation spoiled by that problem.

Yep, my sentiments exactly.  I never owned a Honda before purchasing my '14 Standard.  I had just finished messing with trying to restore a few Yamaha XS650s and realized my skills were far from sufficient, so I decided to go with "solid as an anchor" Honda.  I'm sure they are overall and compared to other brands, but when it happens to you, it just doesn't feel that way.  But...I was so MAD at Honda that I went out and bought another one! 
:huh:
The EX '17 and it's been trouble free, restoring my "faith" in Honda.  

In the end, they are just machines, some behave badly because they are not designed well, others are mistreated, others simply break down because they do.  Kind of like my body!  In the end, my enjoyment of motorcycles and riding in general hasn't waned at all because of truly one, just one, mechanical difficulty.

 

[dave]

There's a lot of good information in this thread; thank you to all who have contributed.

I am one of the group of people who were fortunate enough to have corrected the idle problem on my 2014 DLX by replacing the IACV. I performed this repair approximately ten years, and 30,000 miles ago, and so far it's run perfectly ever since. I still don't understand why the IACV replacement worked for some of us, and not for others. Also, why the majority of owners never experienced an idle problem at all. Based on all the evidence presented, is the real root cause of the idle problem the IACV, or the ECU? Obviously Honda is never going to come clean with an explanation, which is sad. I wonder what would have happened if instead of replacing my IACV when I did I replaced the ECU? Would the new ECU have worked with the original, presumably faulty IACV? Obviously it took Honda a long time, and presumably a lot of work before they were able to answer this question, so none of us are ever going to have the resources to determine the real root cause. That would be so wonderful if someone could publish an explanation in real layman's terms clarifying exactly what went wrong with the bikes that experienced the idle problem, and how replacing the IACV, or ECU, corrected the problem.

 

[1973cb750]

There's a lot of good information in this thread; thank you to all who have contributed.

I am one of the group of people who were fortunate enough to have corrected the idle problem on my 2014 DLX by replacing the IACV. I performed this repair approximately ten years, and 30,000 miles ago, and so far it's run perfectly ever since. I still don't understand why the IACV replacement worked for some of us, and not for others. Also, why the majority of owners never experienced an idle problem at all. Based on all the evidence presented, is the real root cause of the idle problem the IACV, or the ECU? Obviously Honda is never going to come clean with an explanation, which is sad. I wonder what would have happened if instead of replacing my IACV when I did I replaced the ECU? Would the new ECU have worked with the original, presumably faulty IACV? Obviously it took Honda a long time, and presumably a lot of work before they were able to answer this question, so none of us are ever going to have the resources to determine the real root cause. That would be so wonderful if someone could publish an explanation in real layman's terms clarifying exactly what went wrong with the bikes that experienced the idle problem, and how replacing the IACV, or ECU, corrected the problem.

i believe their are some iac failure not common but the majority will have the ecu issue hear the old ecu has a flaw in the firmware so that the idle control fails and stops making the iac function

 

[dave]

Gentlemen,

Since this thread talked a lot about replacing the ECU, I had to ask this question:

I plan to never sell my CB1100. What happens in 10 years from now, when my bike is 26 years old, and my ECU, or another electronic component required to make the bike run, fails? There would be zero chance of getting a replacement ECU from Honda, and I don't believe any aftermarket companies manufacture any. So is searching the junkyards for a used part my only option?

 

[1973cb750]

Oem honda has them in stock

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Might grab one and have a spare

 

[peterbaron]

This idling issue was already widely discussed on the previous CB forum.
There were a few remedies as mentioned above but ultimately the newest ECU version finally solved the idle problem for good.

 

[SportsterDoc]

Gentlemen,

Since this thread talked a lot about replacing the ECU, I had to ask this question:

I plan to never sell my CB1100. What happens in 10 years from now, when my bike is 26 years old, and my ECU, or another electronic component required to make the bike run, fails? There would be zero chance of getting a replacement ECU from Honda, and I don't believe any aftermarket companies manufacture any. So is searching the junkyards for a used part my only option?

I would be inclined to purchase a new ECU and install it to be sure it functions, then run with it or the old.

Not checking this forum often, has anyone replaced the ECU and not solved the idle issue?

In November 2017, I was so very fortunate to purchase a new, still in the crate 2014 CB1100 for $7,249.99 + my 2018 XT250 trade-in.  I wish there was one still available!

[attachment=1191]

 

[Jd2ride]

This thread is only a couple months old. I've tried without success to locate the superseded ECU for my 2014 Standard.
Partzilla and everywhere else I look, list it, A43, as unavailable.
Ebay shows one, but I don't trust it's legit. Anyone have another source to check?

 

[peterbaron]

List the needed OEM P/N to avoid costly mistakes..

 

[1973cb750]

Yes i just looked at the usual spots says un available wth

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38770-MGC-A43

 

[Jd2ride]

That's the same thing I found. Either someone bought all remaining stock up or Honda decided to delete the part for some unknown reason.
Weird for it to vanish like that, either way.

 

[rdprdp01]

Peter is right. Posting the part number you are searching for is the best way to enable the Forum Members to assist.

If 38770MGCA42 is the correct module, Webike has a brand new unit in stock:

HONDA OEM Motorcycle parts : PGM-FIUnit [38770MGCA42] [38770MGCA42]

I have purchased many parts directly from them. For my transactions, they have been incredibly reliable. Customer Service was also strong assisting me with part selection. The shipping costs are high because of the international shipping. Occasionally, I have had to pay tariffs on parts which have a high steel content. Hope this helps. David

 

[LucienLeFranc]

I would be fairly confident the used ECU currently offered on eBay is legit, as the seller is listing many other CB1100 parts, most certainly from a salvaged bike, and--further--eBay makes it easy to get a refund on a faulty part, so someone could buy it, test it in their bike, and get a refund if it isn't a good part.

I also feel that, as the years pass, more and more perfectly good ECUs will appear on eBay as, sadly, CB1100s end up in salvage yards.

Anyone who is particularly worried about this issue might proactively buy a new or used backup ECU now, but for me myself, given my experience with salvage-parts availability for other old rare bikes, I feel pretty confident that  I'll find a perfectly good salvaged ECU if ever I need one.

(My urgency toward acquiring a backup will increase, however, if at some future time I start seeing reports of numerous failing ECUs, so that demand could possibly outpace the supply from salvaged CB1100s.)

 

[peterbaron]

I think the correct, supersede P/N is 38770-MGC-A43 ?

 

[1973cb750]

Yes the 14 is a a43 and the 13’ is a a24

Old is 14 a42. Old 13 is a a23