CB1100 Idle speed instability problem

[736cc_imp]

My 2013 idle when ice cold is 1400 or so BUT rises to 2000 immediately when it’s dropped into 1st gear. Put it back into neutral, it immediately goes down to 1400. After a brief warmup ride of a couple of blocks it idles at 1050 in neutral or in 1st w/ clutch pulled. Why/how does the bike idle speed rise as soon as it’s put into gear BUT only when ice cold? Some stick shift cars (and bikes, too: ie 2018 Suzuki SV650 has this subtle in gear rpm lift-aid to avoid stalling in 1st gear) computers deliberately lift the rpms when put into gear. I never heard this mentioned w/ our CB1100, but mine apparently senses being put into gear and lifts the rpms alot; BUT it’s only when cold. Warmed-up I don’t see any rpms difference from neutral and in gear. Bike runs mint btw after a very brief warm up, and has done so for 24,000 miles.

Comments? Is this perhaps related to the demonic idle possession that afflicts random CB1100’s?? My bike’s computer KNOWS it’s in gear and lifts the idle speed BUT ONLY WHEN ICE-COLD. There must be a gear sensor connected to engine temperature sensor to do be able to accomplish thins.

[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.

Hi Dave, this is my first reply so it may not format well, anyway...

Here's what i did chronologically:

1 Moved the rear of the tank up and removed the black tb cover with the black plastic screw.
2 bike cold and key off removed the connector from the iacv.
3 key on and " 38 " code was displayed by check engine light.
4 started engine and it fired up around 1000 rpm no problem.
5 throttle response was normal and precise.
6 let engine run for a short while before stopping by turning the key off.
7 replaced iacv connector and switched key back on, code "38 " was not displayed, the startup procedure was restored as per normal.
my cb1100 is from 2010 and imported from japan, does not have the idle issue just for your information.

I am considering making a harness for the iacv connector that has different colour led's in it to indicate stepper motor activity in both direction and mount it on the dash just to find out what makes it tick as i drive around.

Unplugging it would point in a direction ( speculation; either iacv stuck or getting the wrong information from the ecm ) and eliminate carbon fouling or such over time.

i do realise i am on thin ice here and hope some idea's may shed a new light

Cheers max

[SportsterDoc]

+1 what popgun says. I think the "real" idle fluctuation affects '14's. Mine does what yours does, occasionally.

Ben

Any correlation to low or high VIN?
In other words, any relation to early or late 2014 models?

In cooler weather now, my 2014 starts and idles about 1300, then drops to about 1050, when warm.

If the EOT sends a higher voltage to the ECU than what corresponds to the appropriate temperature based resistance, then the ECU would be expected drive the IACV to a faster idle. This assumes that the EOT has priority input over the IAT. Not much on the internet, other than this forum.

If the EOT values are within spec, and if the wiring is fully intact, then the IACV would be a prime suspect, unless the TPS feedback to the ECU is at fault.

Before getting into all this, I'd first check for a vacuum leak.

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.

Hi Dave, this is my first reply so it may not format well, anyway...

Here's what i did chronologically:

1 Moved the rear of the tank up and removed the black tb cover with the black plastic screw.
2 bike cold and key off removed the connector from the iacv.
3 key on and " 38 " code was displayed by check engine light.
4 started engine and it fired up around 1000 rpm no problem.
5 throttle response was normal and precise.
6 let engine run for a short while before stopping by turning the key off.
7 replaced iacv connector and switched key back on, code "38 " was not displayed, the startup procedure was restored as per normal.
my cb1100 is from 2010 and imported from japan, does not have the idle issue just for your information.

I am considering making a harness for the iacv connector that has different colour led's in it to indicate stepper motor activity in both direction and mount it on the dash just to find out what makes it tick as i drive around.

Unplugging it would point in a direction ( speculation; either iacv stuck or getting the wrong information from the ecm ) and eliminate carbon fouling or such over time.

i do realise i am on thin ice here and hope some idea's may shed a new light

Cheers max

Input appreciated. 1,000 RPM would be normal idle speed with the idle air control valve deactivated.

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.

Hi Dave, this is my first reply so it may not format well, anyway...

Here's what i did chronologically:

1 Moved the rear of the tank up and removed the black tb cover with the black plastic screw.
2 bike cold and key off removed the connector from the iacv.
3 key on and " 38 " code was displayed by check engine light.
4 started engine and it fired up around 1000 rpm no problem.
5 throttle response was normal and precise.
6 let engine run for a short while before stopping by turning the key off.
7 replaced iacv connector and switched key back on, code "38 " was not displayed, the startup procedure was restored as per normal.
my cb1100 is from 2010 and imported from japan, does not have the idle issue just for your information.

I am considering making a harness for the iacv connector that has different colour led's in it to indicate stepper motor activity in both direction and mount it on the dash just to find out what makes it tick as i drive around.

Unplugging it would point in a direction ( speculation; either iacv stuck or getting the wrong information from the ecm ) and eliminate carbon fouling or such over time.

i do realise i am on thin ice here and hope some idea's may shed a new light

Cheers max

Be interesting to know how many have cleaned the IACV to solve the issue.
I'm inclined to otherwise suspect that the ECU output is inappropriate for operating temperature...again, if there is no vacuum leak.

[flynrider]

My 2013 idle when ice cold is 1400 or so BUT rises to 2000 immediately when it’s dropped into 1st gear. Put it back into neutral, it immediately goes down to 1400. After a brief warmup ride of a couple of blocks it idles at 1050 in neutral or in 1st w/ clutch pulled. Why/how does the bike idle speed rise as soon as it’s put into gear BUT only when ice cold? Some stick shift cars (and bikes, too: ie 2018 Suzuki SV650 has this subtle in gear rpm lift-aid to avoid stalling in 1st gear) computers deliberately lift the rpms when put into gear. I never heard this mentioned w/ our CB1100, but mine apparently senses being put into gear and lifts the rpms alot; BUT it’s only when cold. Warmed-up I don’t see any rpms difference from neutral and in gear. Bike runs mint btw after a very brief warm up, and has done so for 24,000 miles.

Comments? Is this perhaps related to the demonic idle possession that afflicts random CB1100’s?? My bike’s computer KNOWS it’s in gear and lifts the idle speed BUT ONLY WHEN ICE-COLD. There must be a gear sensor connected to engine temperature sensor to do be able to accomplish thins.

How cold is ICE-COLD? After reading your post I went out and tried this on my CB. It was about 55F, which is cold enough to trigger the normal fast idle. I shifted back and forth from 1st and 2nd gear back to neutral and the idle stayed at 1400. If the temp needs to be around freezing to observe this effect, I may have to wait a month or two.

[SportsterDoc]

My 2013 idle when ice cold is 1400 or so BUT rises to 2000 immediately when it’s dropped into 1st gear. Put it back into neutral, it immediately goes down to 1400. After a brief warmup ride of a couple of blocks it idles at 1050 in neutral or in 1st w/ clutch pulled. Why/how does the bike idle speed rise as soon as it’s put into gear BUT only when ice cold? Some stick shift cars (and bikes, too: ie 2018 Suzuki SV650 has this subtle in gear rpm lift-aid to avoid stalling in 1st gear) computers deliberately lift the rpms when put into gear. I never heard this mentioned w/ our CB1100, but mine apparently senses being put into gear and lifts the rpms alot; BUT it’s only when cold. Warmed-up I don’t see any rpms difference from neutral and in gear. Bike runs mint btw after a very brief warm up, and has done so for 24,000 miles.

Comments? Is this perhaps related to the demonic idle possession that afflicts random CB1100’s?? My bike’s computer KNOWS it’s in gear and lifts the idle speed BUT ONLY WHEN ICE-COLD. There must be a gear sensor connected to engine temperature sensor to do be able to accomplish thins.

How cold is ICE-COLD? After reading your post I went out and tried this on my CB. It was about 55F, which is cold enough to trigger the normal fast idle. I shifted back and forth from 1st and 2nd gear back to neutral and the idle stayed at 1400. If the temp needs to be around freezing to observe this effect, I may have to wait a month or two.

Come visit Las Vegas, as we have a freeze warning tonight!
Hope it is mild, as it plays havoc with our citrus trees.

[pdedse]

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.

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/showt...wer+supply ...but it was solved.

There is a 300+ post thread that was fixed by cleaning a chassis/harness ground to the trans: [url=http://xlforum.net/vbportal/forums/showthread.php?t=1891463&highlight=sportsterdoc&page=36]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!

Guidance can be provided? So you're coming over to my garage?

If folks don't want to read 58 pages, there is the spreadsheet, but I'll try here:

Summary: some members have high idle at 1500, some have low at 500, floats up to 700, some have both. A few with low idle their bikes stall, others do not. Some say problem only happens with hot bike, mine acts up cold, hot, short rides, long rides...or it doesn't happen. Has not gone away for longer than 2 rides since July, '17.

What members have done:
1. throttle assembly replacement, under warranty (more than $3,000 if not under warranty). Problem solved.
2. One IACV replacement worked (under warranty, would have been $1,300), one didn't--I think this one was performed by the member
3. WOT riding...worked for some, didn't for others, temporarily "worked" for others
4. battery replacement seeme to "fix" for one member; others have disconnected battery, recharging, problem returned.
5. TPS reset; worked for some, not for others.
6. Wire at TPS connector was crimped? "Fixed" and problem went away (I'm not sure of the details).
7. EOT replaced, didn't work for a couple
8. EOT unplugged, problem goes away, but then comes back.
9. sea foam added, fuel injector cleaners; some say this cured issue, for other no
10. ECU reset; worked? for others didn't
11. some just live with it

I suspect that for some who say the problem went away, that it may not have... some have reported "fixes" only to have the problem return.

My dealer: service manager said he'll do the analysis if I want at $110 per hour; he said up front that if there's no check engine light coming on and if they can't replicate the idle problem, that it would be very difficult to pinpoint, that such work could entail several hours of work that may produce a result, or it may not. Recommended I send my summary letter I left with them to Honda, which I have done. Needless to say, I wasn't inspired and can't see myself going down that path.

I suck at electrical troubleshooting and most of what I read regarding ECU/TPS/EOT/IACV/WOT/TPS/OHM/ACDC/U2/MTV/ROTFL looks like alphabet soup to me.

Be sure to call before coming over as I may be out riding my bike!

[SportsterDoc]

OK, I am finally starting to read this thread.
I have only gone through the first 10 pages/100 posts.
Brief summary:
2: IACV
7: Throttle body
16: Comment that it affects mostly EX models with dual O2 sensors
17: Link to TPS adjustment thread
29: Bad (water?) gas suspected (only affect low idle, not high)
35: TPS reset
49: RPM drops after 15 minutes of riding
58: O2 sensors suspected
59: O2 sensors debated
66: Battery disconnected and reconnected
68: Battery disconnected and reconnected resulted in no change
72: O2 sensors not the issue, but adding slack to throttle play resolved issue
75: Link to added throttle cable zip ties too tight
76: Idle works its way back to normal while idling
87: Riko in Belgium told to expect IACV replacemnt to cure
90: Rico got new throttle body
92: Popgun commented that probably only needed TPS, but not available separately.

Hope to read more, tomorrow.
No conclusion, at this point, but no change to comments/suggestions/questions I have previously posted.

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.

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/showt...wer+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!

Guidance can be provided? So you're coming over to my garage?

If folks don't want to read 58 pages, there is the spreadsheet, but I'll try here:

Summary: some members have high idle at 1500, some have low at 500, floats up to 700, some have both. A few with low idle their bikes stall, others do not. Some say problem only happens with hot bike, mine acts up cold, hot, short rides, long rides...or it doesn't happen. Has not gone away for longer than 2 rides since July, '17.

What members have done:
1. throttle assembly replacement, under warranty (more than $3,000 if not under warranty). Problem solved.
2. One IACV replacement worked (under warranty, would have been $1,300), one didn't--I think this one was performed by the member
3. WOT riding...worked for some, didn't for others, temporarily "worked" for others
4. battery replacement seeme to "fix" for one member; others have disconnected battery, recharging, problem returned.
5. TPS reset; worked for some, not for others.
6. Wire at TPS connector was crimped? "Fixed" and problem went away (I'm not sure of the details).
7. EOT replaced, didn't work for a couple
8. EOT unplugged, problem goes away, but then comes back.
9. sea foam added, fuel injector cleaners; some say this cured issue, for other no
10. ECU reset; worked? for others didn't
11. some just live with it

I suspect that for some who say the problem went away, that it may not have... some have reported "fixes" only to have the problem return.

My dealer: service manager said he'll do the analysis if I want at $110 per hour; he said up front that if there's no check engine light coming on and if they can't replicate the idle problem, that it would be very difficult to pinpoint, that such work could entail several hours of work that may produce a result, or it may not. Recommended I send my summary letter I left with them to Honda, which I have done. Needless to say, I wasn't inspired and can't see myself going down that path.

I suck at electrical troubleshooting and most of what I read regarding ECU/TPS/EOT/IACV/WOT/TPS/OHM/ACDC/U2/MTV/ROTFL looks like alphabet soup to me.

Be sure to call before coming over as I may be out riding my bike!

LOL
Guidance = where to probe

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.

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: [url=http://xlforum.net/vbportal/forums/showthread.php?t=2042781&highlight=power+supply]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: [url=http://xlforum.net/vbportal/forums/showthread.php?t=1891463&highlight=sportsterdoc&page=36]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!

Guidance can be provided? So you're coming over to my garage?

If folks don't want to read 58 pages, there is the spreadsheet, but I'll try here:

Summary: some members have high idle at 1500, some have low at 500, floats up to 700, some have both. A few with low idle their bikes stall, others do not. Some say problem only happens with hot bike, mine acts up cold, hot, short rides, long rides...or it doesn't happen. Has not gone away for longer than 2 rides since July, '17.

What members have done:
1. throttle assembly replacement, under warranty (more than $3,000 if not under warranty). Problem solved.
2. One IACV replacement worked (under warranty, would have been $1,300), one didn't--I think this one was performed by the member
3. WOT riding...worked for some, didn't for others, temporarily "worked" for others
4. battery replacement seeme to "fix" for one member; others have disconnected battery, recharging, problem returned.
5. TPS reset; worked for some, not for others.
6. Wire at TPS connector was crimped? "Fixed" and problem went away (I'm not sure of the details).
7. EOT replaced, didn't work for a couple
8. EOT unplugged, problem goes away, but then comes back.
9. sea foam added, fuel injector cleaners; some say this cured issue, for other no
10. ECU reset; worked? for others didn't
11. some just live with it

I suspect that for some who say the problem went away, that it may not have... some have reported "fixes" only to have the problem return.

My dealer: service manager said he'll do the analysis if I want at $110 per hour; he said up front that if there's no check engine light coming on and if they can't replicate the idle problem, that it would be very difficult to pinpoint, that such work could entail several hours of work that may produce a result, or it may not. Recommended I send my summary letter I left with them to Honda, which I have done. Needless to say, I wasn't inspired and can't see myself going down that path.

I suck at electrical troubleshooting and most of what I read regarding ECU/TPS/EOT/IACV/WOT/TPS/OHM/ACDC/U2/MTV/ROTFL looks like alphabet soup to me.

Be sure to call before coming over as I may be out riding my bike!

Now you tell me!
Where is "the spreadsheet"?
I'd be happy to not read another 48 pages.

[Cormanus]

SportsterDoc, see this thread, http://cb1100forum.com/forum/showthread.php?tid=11247

[max]

Data for Doc;

resistance of cold ( 20 celsius ) eot sensor 2093 ohms. engine starts and runs at 1500 rpm.

after 2 or so minutes the engine dropped to 1100 rpm and i switched it off to measure the resistance with a known accurate fluke digital multi meter and i have made a little connector which plugs into the eot sensor 1/8" spacing molex.

resistance at 1100 rpm. is 453 ohms and dropping ( temp still rising at that time )
this is a moving target as the engine is still transferring heat through the metal but much lower value is likely with a hot engine.

Resistance to engine chassis is infinity ohms ( the sensor floats electrically ).

Voltage takes a bit more work to do accurately.

Some observations; engine does not start with eot sensor disconnected and engine light comes on, it just stutters.

If the engine is started very quickly DURING the initialization phase ( when the meters are cycling ) the rpm's are initially higher and drop quickly to 1050, ( i've noticed this before and did not think it was important until now
this could mean that the iacv starts open and then moves to the desired setting of 1050 rpm.

Again; my cb1100 is from 2010 and does not have any issues.

cheers max

[SportsterDoc]

SportsterDoc, see this thread, http://cb1100forum.com/forum/showthread.php?tid=11247

Thank you. Hopefully that saves reviewing the entire thread.
Thinking out loud:
1. Did not notice any checks for a vacuum leak
2. Not finding consistency in "cures"
3. Not all are low/high issues (may not be due to same cause)

I had a failure to idle issue on my V7II, first experienced at 8,000 feet altitude, ~5 months in service and 6,000 miles. It required throttle to maintain idle, even after returning to 2,200 feet elevation. Cured by tightening band around rubber from single throttle body to intake manifold.

However, it did it again, a couple weeks later in Arizona, on highway 89A going through Jerome (5,000 feet) after descending from a 7,000 foot summit. Continued to be an issue while giving grandkids rides around Clarkdale (~3,500 feet elevation)

Because of fueling issues starting cold or warm, I figured it was an ECU program issue...and the dealer had already downloaded what was supposed to be the latest program. Told my daughter that if Kingman Harley/Honda/etc. had a CB1100 I would trade it on the way home, as I did not want to deal further with the Las Vegas MG dealer.

Checked valves that evening and rode home the next morning, going back over Mingus Mountain. By the time I got to Chino Valley to refuel, idle was normal and stayed normal until I traded the bike. Took I40 instead of Route 66 and the Moto Guzzi ran strong at ~85 MPH for 80 miles to Kingman. Kingman did not have a CB1100.

Data for Doc;

resistance of cold ( 20 celsius ) eot sensor 2093 ohms. engine starts and runs at 1500 rpm.

after 2 or so minutes the engine dropped to 1100 rpm and i switched it off to measure the resistance with a known accurate fluke digital multi meter and i have made a little connector which plugs into the eot sensor 1/8" spacing molex.

resistance at 1100 rpm. is 453 ohms and dropping ( temp still rising at that time )
this is a moving target as the engine is still transferring heat through the metal but much lower value is likely with a hot engine.

Resistance to engine chassis is infinity ohms ( the sensor floats electrically ).

Voltage takes a bit more work to do accurately.

Some observations; engine does not start with eot sensor disconnected and engine light comes on, it just stutters.

If the engine is started very quickly DURING the initialization phase ( when the meters are cycling ) the rpm's are initially higher and drop quickly to 1050, ( i've noticed this before and did not think it was important until now
this could mean that the iacv starts open and then moves to the desired setting of 1050 rpm.

Again; my cb1100 is from 2010 and does not have any issues.

cheers max

Max

That you for your post and the effort taken to provide the data.

I learned with H-D, 15 years ago, that it is best to let gauges fully cycle before starting. And that was with a carbed bike, no ECU, just an ignition module.

What I'm looking for are

1. EOT specs from the factory manual

Here is a link to a chart (see bottom) to serve as an example, but not likely the same scale: http://www.diesel-dave.com/vehic/manual/...118087.htm

2. Someone with on ongoing idle issue to test the EOT for resistance at various temperatures. This would best be done by removing the EOT and measuring resistance while varying the temperature. One way is to submerge the tip into water and slowly heating it while monitoring with a thermometer and ohmmeter connected.

This could help determine if an out of spec EOT is an issue or not.