CB1100 Idle speed instability problem

[flynrider]

This problem is getting curiouser and curiouser...

I'll say!

What I find interesting is that the problem only seems to show up in stop-n-go city riding. My '13 displayed the low idle condition just once (at 18K miles), after a few weeks of just stop and go city riding. After that I went back to a more normal routine which included making some power on the freeway. Haven't seen the problem recur (it's been about 3 months).

Given the number of variables involved in the system (ECU programming, numerous sensors, control motors, etc...) I don't hold out much hope that we'll be able to isolate the cause of the issue in this thread. It's one of those needle in a haystack things.

Since Honda uses these same components in other bikes without issue, I have to wonder what makes our bikes different? The obvious thing is that our bikes are air cooled, which results in a much wider range of combustion temperatures. Q: Is there any other large air cooled engine that Honda has equipped with this PGM-FI system?

[Riko_imp]

riding style, Lol

anyway, be sure to show him my video of the issue (thats resolved by simply changing the whole throttle body, under warranty)





there is nothing more clear to show an issue like a good video
images say more than words

I think he was referring to throttle use.

I think he was referring to throttle use.
I know

but even the slightest hint of tought of linking riding style as a possible cause of the throttle issue is absurd

all this evolution in automotive and electronical technology such as Fuel Injection, makes his conclusion a joke tbh, especially when you think about it

sounds like a desperate mechanic to me

I think he was referring to throttle use.
I know

but even the slightest hint of tought of linking riding style as a possible cause of the throttle issue is absurd

all this evolution in automotive and electronical technology such as Fuel Injection, makes his conclusion a joke tbh, especially when you think about it

sounds like a desperate mechanic to me
Well I guess you'd better just go sort it yourself then.

There's always those that know best. I was just passing on his comments, and what Ferret says above is in fact just what this guy said to me re the machine 'learning' it's operator. Change the operator and there may be problems. He went on to say that the bike manufacturers are quite open about their fuel injection systems being technically behind those of the car industry.
He was just talking, thinking out aloud and calmly throwing out ideas and possible causes, certainly nothing desperate about him and he certainly wasn't desperately trying to skirt the issue.

I think he was referring to throttle use.
I know

but even the slightest hint of tought of linking riding style as a possible cause of the throttle issue is absurd

all this evolution in automotive and electronical technology such as Fuel Injection, makes his conclusion a joke tbh, especially when you think about it

sounds like a desperate mechanic to me
Well I guess you'd better just go sort it yourself then.

There's always those that know best. I was just passing on his comments, and what Ferret says above is in fact just what this guy said to me re the machine 'learning' it's operator. Change the operator and there may be problems. He went on to say that the bike manufacturers are quite open about their fuel injection systems being technically behind those of the car industry.
He was just talking, thinking out aloud and calmly throwing out ideas and possible causes, certainly nothing desperate about him and he certainly wasn't desperately trying to skirt the issue. thats the point, we cant seem to soet it, nor trained mechanics and if so called trained mechanics answer quastions just to give an answer, thats no help at all.

Btw it got 'sorted' by changing my whole throttle body.

ECU was left alone...

This problem is getting curiouser and curiouser...

I'll say!

What I find interesting is that the problem only seems to show up in stop-n-go city riding. My '13 displayed the low idle condition just once (at 18K miles), after a few weeks of just stop and go city riding. After that I went back to a more normal routine which included making some power on the freeway. Haven't seen the problem recur (it's been about 3 months).

Given the number of variables involved in the system (ECU programming, numerous sensors, control motors, etc...) I don't hold out much hope that we'll be able to isolate the cause of the issue in this thread. It's one of those needle in a haystack things.

Since Honda uses these same components in other bikes without issue, I have to wonder what makes our bikes different? The obvious thing is that our bikes are air cooled, which results in a much wider range of combustion temperatures. Q: Is there any other large air cooled engine that Honda has equipped with this PGM-FI system?

Since Honda uses these same components in other bikes without issue, I have to wonder what makes our bikes different? The obvious thing is that our bikes are air cooled, which results in a much wider range of combustion temperatures. Q: Is there any other large air cooled engine that Honda has equipped with this PGM-FI system?
looking at their lineup on the website, the CB1100 is the only aircooled bike using the modern pgm fi system

[dave]

So, I'm not the only one who experienced an improvement after the WFO ride! Here's an update, and also some more information to ponder: I've put about 600 miles on my bike since the WFO ride I described that (coincidentally?) cured my fast idle / slow idle / stalling. The bike has for the most part been running better than new, except for one extended slow speed, stop and go ride where the idle would momentarily drop to 750 RPM (it used to drop to 500 RPM and sometimes stall) and then return to normal (1,050 RPM) - this happened three times. If you're experiencing the idle problems, please comment on the following: johnf514 uploaded a video (at my request) of the sound his fuel pump and IACV make as you turn the ignition on. John had his IACV replaced by the dealer, and it cured his idle problem. Listen to John's video and you can hear the IACV cycling rather loudly (the fuel pump has it's own sound). When my bike experiences the idle problems I can barely hear the sound of the IACV cycling when I turn on the ignition. When my bike is running good (no idle problems), the sound of the IACV cycling when you turn on the key is MUCH louder, and sounds exactly like the video johnf514 recorded. Please listen to John's video (it can be found somewhere in this thread), and then listen to the sounds your bike makes - do they sound the same? Something tells me that when you can barely hear the sound of the IACV cycling when you turn the key on then you're going to experience the idle problems. So the question is this: Is the problem with the IACV, or with the software or sensor that gives the signal to the IACV?

[Lord Popgun]

Or is it not cycling correctly? Like maybe hanging up or somthing. I'd like to see how they have it mounted and how it operates in the throttle body. But, I'm not taking my bike apart to find out. I hope...

[johnf514_imp]

Here is the video Dave referenced:

https://www.youtube.com/watch?v=SsKgL0FdgYA

[dave]

Here is the video Dave referenced:

https://www.youtube.com/watch?v=SsKgL0FdgYA

Thanks John. Actually, mine is not as loud as yours sounds. I am anxious to hear feedback from others on how theirs sounds.

[Riko_imp]

normal

[Sandhog_imp]

My bike also sounds normal.

Most recently I've been having the high-idle issue (1500+ rpms). The mechanic at dealership believes replacing the EOT Sensor may fix the problem. I'm heading down the dealership tomorrow so they can replace the part.

[dave]

My bike also sounds normal.

Most recently I've been having the high-idle issue (1500+ rpms). The mechanic at dealership believes replacing the EOT Sensor may fix the problem. I'm heading down the dealership tomorrow so they can replace the part.

Unplugging the EOT sensor will cure the problem, but then your "check engine" light and the engine temperature light will both be on. I replaced my EOT sensor and it did not cure the problem. BTY - it's a simple, 10 minute job to do it yourself.

[Sandhog_imp]

My bike also sounds normal.

Most recently I've been having the high-idle issue (1500+ rpms). The mechanic at dealership believes replacing the EOT Sensor may fix the problem. I'm heading down the dealership tomorrow so they can replace the part.

Unplugging the EOT sensor will cure the problem, but then your "check engine" light and the engine temperature light will both be on. I replaced my EOT sensor and it did not cure the problem. BTY - it's a simple, 10 minute job to do it yourself.

Unplugging the EOT sensor will cure the problem, but then your "check engine" light and the engine temperature light will both be on. I replaced my EOT sensor and it did not cure the problem. BTY - it's a simple, 10 minute job to do it yourself.
Dave, I hear you, thanks. The bike is under warranty so I want Honda to work through the diagnostic / repair process otherwise I would just take a gamble and purchase and replace the part myself. I really like the CB1100 but these engine idle issues are the pits.