CB1100 Idle speed instability problem

[GoldOxide_imp]

It's been 2.5 years since I replaced the IACV on my 2014EX and I've had no more low idle issues.

Right after I replaced the IACV, the dealership uploaded a patch to my ECU that he'd gotten from Honda since 2014.
So I don't know which of the two fixed the problem.

Right after I replaced the IACV, the dealership uploaded a patch to my ECU that he'd gotten from Honda since 2014.
So I don't know which of the two fixed the problem.
Interesting note of observation Enzofour.

How much time/riding done between the two events? Minutes? Hours? Days?

 

[Enzofour_imp]

It's been 2.5 years since I replaced the IACV on my 2014EX and I've had no more low idle issues.

Right after I replaced the IACV, the dealership uploaded a patch to my ECU that he'd gotten from Honda since 2014.
So I don't know which of the two fixed the problem.

Right after I replaced the IACV, the dealership uploaded a patch to my ECU that he'd gotten from Honda since 2014.
So I don't know which of the two fixed the problem.
Interesting note of observation Enzofour.

How much time/riding done between the two events? Minutes? Hours? Days?

Right after I replaced the IACV, the dealership uploaded a patch to my ECU that he'd gotten from Honda since 2014.
So I don't know which of the two fixed the problem.
Interesting note of observation Enzofour.

How much time/riding done between the two events? Minutes? Hours? Days? 5/6 days

 

[dave]

It's been nearly five years and 17,000 miles since I replaced the IACV on my 2014 Dlx, and the idle problem has never returned. I tried disconnecting and grounding the battery, and it didn't work. A previous post stated that performing the battery disconnect and grounding resulted in a temporary fix, but I think the "fix" was a mere coincidence because my idle problem came and went at will, totally unpredictably.

For all the work I went through to replace the IACV (I followed the Honda service manual and removed the entire rear fender to allow clearance to remove the airbox) I would have prefered to replace, or reprogram the ECM, but the reprogram option wasn't available five years ago, and I had no information available then that replacing the ECM would work. My bike was examined by an authorized Honda dealer at that time, under warranty, and they performed a computer diagnosis that didn't find any errors. As luck would have it, the problem was not present when I delivered the bike to the shop.

 

[1973cb750]

It's been nearly five years and 17,000 miles since I replaced the IACV on my 2014 Dlx, and the idle problem has never returned. I tried disconnecting and grounding the battery, and it didn't work. A previous post stated that performing the battery disconnect and grounding resulted in a temporary fix, but I think the "fix" was a mere coincidence because my idle problem came and went at will, totally unpredictably.

For all the work I went through to replace the IACV (I followed the Honda service manual and removed the entire rear fender to allow clearance to remove the airbox) I would have prefered to replace, or reprogram the ECM, but the reprogram option wasn't available five years ago, and I had no information available then that replacing the ECM would work. My bike was examined by an authorized Honda dealer at that time, under warranty, and they performed a computer diagnosis that didn't find any errors. As luck would have it, the problem was not present when I delivered the bike to the shop.

you may have had a iac failure not impossible

 

[pdedse]

It's been nearly five years and 17,000 miles since I replaced the IACV on my 2014 Dlx, and the idle problem has never returned. I tried disconnecting and grounding the battery, and it didn't work. A previous post stated that performing the battery disconnect and grounding resulted in a temporary fix, but I think the "fix" was a mere coincidence because my idle problem came and went at will, totally unpredictably.

For all the work I went through to replace the IACV (I followed the Honda service manual and removed the entire rear fender to allow clearance to remove the airbox) I would have prefered to replace, or reprogram the ECM, but the reprogram option wasn't available five years ago, and I had no information available then that replacing the ECM would work. My bike was examined by an authorized Honda dealer at that time, under warranty, and they performed a computer diagnosis that didn't find any errors. As luck would have it, the problem was not present when I delivered the bike to the shop.

I remember reading of your issues, having similar things going on...but mine was out of warranty by six months. I contacted Honda CS and they said since it was close, that MAYBE they would listen, but I had to go through dealership who said MAYBE 1 hour, maybe 5 hours at $125 per hour to diagnose. It needed new tires and was due for valve check...traded it in on Speed Twin, which in turn, morphed into having another go with the '17ex.

My true "out the door price" (everything including 4 years registration) for the '14 standard was $7000 and I got 4600 back. This was way before spike in vehicle prices overall. Owned it nearly 2 years, put 10k miles on it. Not ideal, but I think I saved myself a lot of running around as nearest dealer is 45 minutes away, over an hour if any traffic.

I am grateful that the ex has not had any issues related to idling.

 

[dave]

Gentlemen: I've been doing some research on ECM part numbers and discovered that not only has the ECM part number been superseded, but different Honda CB1100 models used different part numbers for the same year.

I believe the reason for the different ECM part numbers used for the same year is because the Standard (single pipe) and the Deluxe (two pipe) models required different parts. Can someone please explain why this is so? Partzilla identifies the different models using a model designation: CB1100SA AC (Deluxe?) versus CB1100AC (Standard?). Chaparral Motorsports uses VIN numbers to differentiate between the two models.

Chaparral identifies the old, and superseded part numbers for year 2014:
VIN JH2SC658-EK000001: OLD 38770-MGC-A73 NEW 38770-MGC-A74
VIN JH2SC651-EK100001: OLD 38770-MGC-A42 NEW 38770-MGC-A43

I just visited the Partzilla website, and for the 2014 model they do NOT list a superseded part number. I assume that if you place your order with Partzilla for the old part number they will automatically update it with the superseded part number.
CB1100SA-AC: 38770-MGC-A73
CB1100 AC: 38770-MGC-A42

I also discovered on the Partzilla website that the ECM part number for the year 2017 model(s) CB1100CA AC - CB100CA is: 38770-MGC-A41.

I apologize if this information has been shared previously, but as I was reading through the most recent posts I became confused with the part numbers identified, and had to verify for myself. Your comments and clarifications are most welcome.

 

[1973cb750]

the dlx has a larger tank so the fuel gauge things are diff also more o2 imputs also abs will be different as well

 

[dave]

the dlx has a larger tank so the fuel gauge things are diff also more o2 imputs also abs will be different as well

Thank you CB

 

[Nachodaddy]

When I replaced my ECU, I did not realize there were so many different ones for so many years and models of what I thought was the same motorcycle, the Honda CB1100. I am not a mechanic and I have no confidence in the shops in this area to diagnose and fix this problem, so I was willing to try what I could to fix it. I put part number 38770-MGC-A23 in Google and Partzilla had it. When I went to their site to order it, the number on the screen changed to 38770-MGC-A24. When it arrived, it looked identical to the one on my bike. It worked and continues to. I would have been real happy if the new IACV had fixed my problem, but it didn't. It continues to amaze me that so many people in so many parts of the WORLD with so many different model and years of this model of Honda motorcycle have had this similar problem and Honda has completely ignored it.

 

[max]

Just posting some images for Peter here, just ignore for now please;

Headlight bucket test probe;



Cheers max

 

[Enzofour_imp]

For all the work I went through to replace the IACV (I followed the Honda service manual and removed the entire rear fender to allow clearance to remove the airbox) I would have prefered to replace, or reprogram the ECM, but the reprogram option wasn't available five years ago, and I had no information available then that replacing the ECM would work. My bike was examined by an authorized Honda dealer at that time, under warranty, and they performed a computer diagnosis that didn't find any errors. As luck would have it, the problem was not present when I delivered the bike to the shop.
[/QUOTE]

you did this?

I disassembled less

 

[peterbaron]

Just posting some images for Peter here, just ignore for now please;

Headlight bucket test probe;



Cheers max

Ok moderators, I am done with this diagram and it can be deleted to comply with the regulations.
Thanks
:beerchug:

 

[dave]

How much forcing and bending to the air box did you have to do to get it to squeeze out? I was afraid I would break the air box if I tried to force it out.
It continues to amaze me that so many people in so many parts of the WORLD with so many different model and years of this model of Honda motorcycle have had this similar problem and Honda has completely ignored it.
[/QUOTE]
Does anyone know if Honda "secretly" released a service bulletin to its dealers with instructions for repairing the idle issue? I don't know what the name for it is, but basically the manufacturer keeps all information about the problem quiet, and never releases any information to any of the unsuspecting customers. In this case it looks like the secrete service bulletin would be a replacement of the ECM with the new (updated) part number.

 

[the Ferret]

I know there was never said anything to US dealers. My tech would have told me.

 

[peterbaron]

Just posting some images for Peter here, just ignore for now please;

Headlight bucket test probe;



Cheers max

Max , sorry for late response, here are the results:

Conditions:
2014 CB1100 Std, fully charged battery at 12.5V, red killer switch in "kill" position
black-10 pin connector/double row of 5 pins
wires: white to red-white

* ignition OFF = NO voltage

* ignition ON = 9.8V

* engine running = 12.5V

Cheers

 

[Lord Popgun]

PB,

No Flukes in Canada?

 

[peterbaron]

PB,

No Flukes in Canada?

The last one was shipped to Virginia, Norfolk area

 

[max]

Peter thanks very much for measuring this very precisely and well documented,

This is likely the " keep alive " supply that supplies voltage to the ecu's memory when the ignition is switched off.
It could be used to simulate a " battery reset " every time the bike is switched off for some time and maybe aid in solving the ii issue.

It would require a small relay in line with this wire which is energized when the ignition is switched on and de-energized ( off ) when the ignition is switched off.

All the wiring is accessible inside the headlamp bucket to do this modification if someone would try this out in favour of replacing the ecu.

Any thoughts on this procedure?

 

[peterbaron]

NP. ... when you asked me to do that test, I already new what your plan was.., very smart :beerchug:

 

[max]

NP. ... when you asked me to do that test, I already new what your plan was.., very smart :beerchug:

Yeah so please ignore the pm reply, i read the result wrong the first time

Boy that was quick!!