CB1100 Idle speed instability problem

Carbon build up around IACV? So I replaced my IACV about six months ago and I still had my high idle issue for several months after. Then I finally went on a really hard 200 mile ride in warm weather through the mountains. Afterwards no more high idle. Others have reported a good long hard ride fixing their idle problem as well.

Maybe the long ride is burning off carbon deposits around the IACV that might be causing it to stick?
 
The WFO run cured my bike of its high / low-stalling issue, but only temporarily. It's had been running good for over 1,000 miles. Put about 250 miles on it last Sunday. Had the throttle wide open a few times out on the desert roads where I made some passes, but never ran it to redline. Bike ran perfect all day. Ran it about 80 mph average on the freeway the last 25 miles, and when I pulled off the freeway and stopped at the intersection it stalled. Restarted it, and the idle issue was just as everybody else has described - 500 RPM, then slowly creeping up. Stopped at the next light and was back to 500 RPM idle, but I twisted the throttle to keep it from stalling. Came to the next light (just a few hundred yards), and it stalled. Pulled into my driveway about 1/2 mile later and I shut it off as soon as I saw it was going to do the same, 500 RPM idle again. Put the bike away and forgot about it - I'm sure it will idle fine the next time I ride it.

Am I the only owner in America who has contacted the Honda Factory directly to discuss this situation? I posted a name and phone number at Honda somewhere on this thread if anyone is interested. Honda is not going to do anything unless we make some noise, and the more of us contacting them then better the chance that they will do something.
 
Dave_imp said:
The WFO run cured my bike of its high / low-stalling issue, but only temporarily. It's had been running good for over 1,000 miles. Put about 250 miles on it last Sunday. Had the throttle wide open a few times out on the desert roads where I made some passes, but never ran it to redline. Bike ran perfect all day. Ran it about 80 mph average on the freeway the last 25 miles, and when I pulled off the freeway and stopped at the intersection it stalled. Restarted it, and the idle issue was just as everybody else has described - 500 RPM, then slowly creeping up. Stopped at the next light and was back to 500 RPM idle, but I twisted the throttle to keep it from stalling. Came to the next light (just a few hundred yards), and it stalled. Pulled into my driveway about 1/2 mile later and I shut it off as soon as I saw it was going to do the same, 500 RPM idle again. Put the bike away and forgot about it - I'm sure it will idle fine the next time I ride it.

Am I the only owner in America who has contacted the Honda Factory directly to discuss this situation? I posted a name and phone number at Honda somewhere on this thread if anyone is interested. Honda is not going to do anything unless we make some noise, and the more of us contacting them then better the chance that they will do something.
Click to expand...
Sorry to hear of your troubles.

I have my letter all written up detailing everything, just haven't sent it in yet. I'll look for the address. And then I'll call as well; hopefully this Thursday morning.
 
I forgot to contact Honda, but Dave sent me a message asking if I had, so thanks for the reminder. I called and left a message for a lady named Kelly. Dave spoke with her in August, but no real offer of help. Here's Honda's customer service info:

Kelly. 866-784-1870, extension 13810.

Motorcycle Division, American Honda Motor Company, Inc.
P.O. Box 2220
Torrance, California 90509 – 2200

I've sent them a letter as well.

If you're having this problem here in the U.S., please consider contacting Honda. Squeaky wheel thing.
They need to hear from us.

My dealer told me he was not confident in finding a fix with a 1 hour "analysis" when we couldn't replicate the problem at the shop and no warning/service info indicated on the bike. He said we may end up spending hours ($$$) chasing a fix, and recemmended contacting Honda. If under warranty, yes it would be a different matter.
 
Here's Honda's customer service info:

Kelly. 866-784-1870, extension 13810.

Motorcycle Division, American Honda Motor Company, Inc.
P.O. Box 2220
Torrance, California 90509 – 2200

I've sent them a letter as well.

If you're having this problem here in the U.S., please consider contacting Honda. Squeaky wheel thing.
They need to hear from us.

Thanks Paul. Please keep the forum updated on your progress.

My low idle / stalling has returned sporadically now, but it runs excellent in-between. Somehow my high idle has not returned in over six months.
 
Here’s the latest concerning my low RPM/stalling turned high RPM (1,500 RPM), turned low RPM/stalling again situation. Maybe my post will give somebody an idea that may somehow lead to a solution? My bike had been running nearly perfectly for the past (approx.) 2,000 miles, and now the last three times I have ridden it after it reaches operating temperature it will go into the low RPM/stall mode when I attempt to allow it to idle in neutral at a stop light. I can keep it running by blipping the throttle, and if I blip the throttle enough times it will eventually “slowly” work its way from about 500-600 RPM up to the normal 1050 – 1100 RPM. I can definitely say the low RPM/stalling is not caused by excessive heat, or slow moving/stop-and-go driving. I reached home tonight when the bike was experiencing the low RPM/stalling condition and it stalled as I drove into my driveway. I turned off the key, and after getting a flashlight I unplugged the Engine Oil Temperature (EOT) sensor and restarted the bike. Mysteriously, it began idling fine, at approximately 1,050 RPM. I went on a short ride in the neighborhood and did multiple stop and goes, and the low RPM/stalling did not return. I returned home and turned the bike off with the key, and plugged the EOT sensor back in. I restarted the bike and it was idling fine. I went for a short stop-and-go ride around the neighborhood again and the low RPM/stalling condition came right back. I pulled into my driveway and kept the bike running by blipping the throttle until it eventually “slowly” worked its way back up to a normal, 1050 RPM idle. As I allowed the bike to sit and idle I disconnected the EOT sensor, and the engine immediately stalled. I restarted the bike (the key was never switched off), and with the EOT sensor disconnected the low RPM/stalling condition was back. I turned the bike off using the key and let it sit for about a minute, and restarted it. This time, with the EOT sensor disconnected, it returned to a normal idle. I turned the bike off with the key, plugged the EOT sensor back in and restarted it, and it was idling fine again. In frustration I put the bike in the garage and walked away. So my observation is this: If I am experiencing a low RPM/stalling condition and turn the bike off using the key and unplug the EOT sensor, the condition will go away when I restart it. If, when I am experiencing the low RPM/stalling condition and I disconnect the EOT sensor without turning the bike off using the key, the low RPM/stalling condition will not go away (it may actually get worse). For some reason the bike needs to be shut down prior to disconnecting the EOT sensor for this procedure to have any positive effect. Does this information possibly provide a hint to a solution to any of you guys out there who have a much better knowledge of how these computer-controlled fuel injection systems work?
 
Hi Dave, i just got my 1100 some months ago and just found out where the iacv actually is, so i am very unqualified to deal with the problem.
Interesting effect with the eot sensor!

However, to me there are two ways the ecm can control the rpm of the bike:
1 : fuel delivery through injectors, and
2 : operate the iacv.

Can i suggest to disconnect the iacv ( unplug the connector ) and see what if any the effect has on the situation.
There will be a trouble code 38 on the engine light ( i have just tried it ) which will go away if the connector is re-connected.

It may have no effect at all but then we have another clue to work with.
This fault just intrigues me having read all the posts in this thread ( a very good one ).

The utterly unqualified; max
 
Hi Max. Thank you very much for the feedback. After you unplugged your IACV did you try to start it?

I'll give it a try ASAP - been really busy with the holidays fast approaching.
 
Dave

If you will provide resistances of the EOT at a couple sensor temperatures...

Then if someone with a FSM will post the acceptable ranges, we can determine if it is an EOT sensor issue.

Temperature sensors have various ranges, but all I have seen have max resistance cold and minimum resistance hot.

On a 5 vdc circuit, it will output 4 point something vdc cold and point something vdc hot. If the unit is faulty and/or a poor connection (causing voltage drop), a lower than scale read will fool the ECU into thinking it is too hot and the ecu may take counter measures.

Also, someone with a FSM, is there a trouble code for EOT out of range hi or out of range low?
 
Keep in mind we know about the EOT and idle speed when it is disconnected. A couple of guys then changed the EOT and the idle problem did not go away.
 
Lord Popgun_imp said:
Keep in mind we know about the EOT and idle speed when it is disconnected. A couple of guys then changed the EOT and the idle problem did not go away.
Click to expand...
Good to know.
Was resistance checked on wiring from EOT to ECU?
Probably not an issue for the G/O to A18, since it is a common ground for EOT, plus O2, MAP, TP and IAT.

The R/Bu to B217 should be well under 0.1 ohm.
Concern would be voltage drop.

Might want to compare R/Bu voltage at EOT and then at the ECU.
dsan1964_imp said:
My bike has been on a high idling kick. Right about 1400. A little irritating


Sent from my iPhone using Tapatalk
Click to expand...
I am a newcomer to this forum, so I am just starting to come up to speed, but might be able to help with some electrical diagnosis.

a. How many miles?

b. Type of riding? such as short trips which may lead to carbon build-up

c. High idle each time it returns to idle? If not, under what conditions?

d. If this were a Sportster, I'd suggest checking the rubber intake boots at carb or throttle body for leaks (very frequent issue). On the pre 2007 Sportster carb models, check the vacuum lines to vacuum operated petcock and VOES. So, on the CB, what are potential sources for a vacuum leak? https://www.bikebandit.com/oem-parts/2014-honda-cb1100/o/m155474#sch848000
 
To tell you the truth Doc, I don’t think any real troubleshooting has been done by anyone. At least not what I would do as a technician, or you as a bike repair specialist.

I wish we could find a common cause for this. So far the fixes have been all over the place. Some had actual failures (at least one IACV) and some cured the problem without really determining the failure (think Rico and the dealer changing out the throttle body), or even a software update for one member somewhere in Europe (Honda of America says there is no update).

As member’s bikes develop the problem, they don’t want to read 56 pages of comments (don’t blame them) and thus the same info, like the EOT affects idle, come out. Yes I know, it COULD be the problem that bike.
 
Lord Popgun_imp said:
To tell you the truth Doc, I don’t think any real troubleshooting has been done by anyone. At least not what I would do as a technician, or you as a bike repair specialist.

I wish we could find a common cause for this. So far the fixes have been all over the place. Some had actual failures (at least one IACV) and some cured the problem without really determining the failure (think Rico and the dealer changing out the throttle body), or even a software update for one member somewhere in Europe (Honda of America says there is no update).

As member’s bikes develop the problem, they don’t want to read 56 pages of comments (don’t blame them) and thus the same info, like the EOT affects idle, come out. Yes I know, it COULD be the problem that bike.
Click to expand...
I have not read the 56 pages, either!

My first thought is a vacuum leak, but I do not know how likely that is on the CB. That can be checked by applying an unlit propane torch at possible areas and listen for a change in idle speed. Some folks like WD-40, but it is messy and some WD-40 is reported to have a non-volatile propellant.

If the EOT is a possible suspect, then we need:

1. Resistance and/or voltage values at various temperatures from the factory service manual.

2. Forum members with the issue to:
a. provide EOT resistance values.
b. provide voltage output values, both at EOT and at the ECU. If not familiar with a multimeter, guidance can be provided.

Sometimes the process can be prolonged, as in the case of this thread on which I was only of minor help: http://xlforum.net/vbportal/forums/showthread.php?t=2042781&highlight=power+supply ...but it was solved.

There is a 300+ post thread that was fixed by cleaning a chassis/harness ground to the trans: http://xlforum.net/vbportal/forums/showt...oc&page=36

Has anyone reported any codes associated with this issue?...guess I need to read the entire thread!
 
As far I know, no codes set, except for the recent unseated pin on a TPS connector. And due to costs, no substitution of the ECU either.

We do know that having Don Guhl flash the ECU for RPM and max speed changes do not cure the problem.
 
Lord Popgun_imp said:
To tell you the truth Doc, I don’t think any real troubleshooting has been done by anyone. At least not what I would do as a technician, or you as a bike repair specialist.

I wish we could find a common cause for this. So far the fixes have been all over the place. Some had actual failures (at least one IACV) and some cured the problem without really determining the failure (think Rico and the dealer changing out the throttle body), or even a software update for one member somewhere in Europe (Honda of America says there is no update).

As member’s bikes develop the problem, they don’t want to read 56 pages of comments (don’t blame them) and thus the same info, like the EOT affects idle, come out. Yes I know, it COULD be the problem that bike.
Click to expand...
This was beardywierdy in the UK.
 
Ok. Gonna jump in here without ever having read extensively about the idle problem. Looking for a quick y/n answer to the following:

The idle on my new 2013 has a tendency to fluctuate between 1,000 and 1,100/1150 rpm when I’m stopped at a stoplight. Doesn’t happen all the time. Is the “idle instability” of which you are speaking?
 
No MTC, not really. They report like a low of 500 and high of 1400-1500. Maybe somewhat higher. I don’t remember the exact numbers but they are in the thread.

Mine does pretty much what yours does. I don’t pay it any mind.
 
+2 to popgun’s comment.
 
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