CB1100 Idle speed instability problem

I used the CB to run errands Saturday morning. Turned off, and restarted the motor 7 times. While not stop-and-go city driving, it was still around town that required probably twenty stops and starts, each that caused the engine to idle for the length of an average stoplight. Temperature was in the low seventies. Approximate total miles were 15. Bike ran perfectly, idling at exactly 1050 RPM each time. It’s too early to conclude that the idle problem is 100% cured at this time, but it is looking good. I will post new information as I add up the miles.
 
Update: Tightening the loose throttlebody connection clamps does not cure the low idle problem. Here’s a description of my experience with the low idle condition returning last evening. The temperature was in the low 60’s. Bike started normally, and I proceeded 1 mile to the freeway, stopping at two stop lights, where the idle was normal. Proceeded 28 miles on the freeway, averaging 70 mph, and exited. Immediately at the first stop light the idle dropped to 700 RPM, and worked its back up to approximately 1,000 RPM. I proceeded about 2 miles to my destination, stopping at 4 more stop lights and each time he 700 RPM condition returned. When I reached my destination I put the bike in neutral and revved the engine several times; each time the 700 RPM condition returned. I turned the engine off with the key, restarted it, and no change. I turned the engine off again; turned the key to “on” and performed the TPS reset procedure, and then turned the key off. I restarted the bike and it was running perfectly. Note: I have performed this exact same TPS reset procedure several times in the past when the low idle condition occurred and it never worked before. The bike sat for approximately 2 hours before I restarted it for my return trip. It started normally, and idled fine at the first stop, approximately 100 yards away. Stopping at the next light, approximately 200 yards away, the low idle condition returned. I put the bike in neutral and revved it several times with no change, except this time it stalled once. I performed the TPS reset as described above and the problem was cured. I proceeded to the freeway and stopped at three more lights, where the idle was fine. The temperature was now in the mid 50’s, and I rode the freeway 28 miles, averaging 70 mph. Exiting the freeway and at the first 2 stop lights the idle dipped lower than normal, but not to 700 RPM, and worked its way back up. When I reached home, 1 mile from the freeway, the 700 RPM condition returned. I again revved the engine in neutral, with no change in idle speed. In my opinion, when the low idle condition returns the engine seems to be running lean, because it does not respond to throttle input as readily. I turned the engine off with the key and restarted it with no change. I performed the TPS reset described above and the low idle condition was cured. I next turned the engine off and unplugged the TPS, and restarted it. I was idling at approximately 1,000 RPM, but throttle response was weak, very similar to the response when the low idle condition was present. I revved the engine several times with the TPS unconnected, and it would return to approximately 1,000 RPM each time, but the throttle response remained weak. (The check engine light was illuminated.) I turned the engine off and plugged the TPS back in and restarted it, and it was running perfectly again. There was a very obvious difference in throttle response from when the TPS was disconnected. I revved the motor several times, and each time it returned to a perfect 1,050 RPM. I turned the engine off and parked the bike. Note: When the low idle condition returns the engine speed drops much quicker than normal, which I noticed especially when shifting gears because the immediate drop to low RPM when shifting causes noisy shifts, caused by the chain slack loosening and tightening. So in summary, tightening the loose throttlebody clamps does not cure the low idle condition.
 
1. MOST common mistake in trying to "repair/find" problems is replacing parts, more parts... or complete segment/ass-y prior diagnosing. So even if the presumed problem is fixed with guaranteed 100%, no one knows what was wrong.Angry
2. Watching 5 min video clip/idle up and down tells me what tach is doing, instead of where eventual problem is located.
3. Most members are not troubleshooting oriented (normality, they have their skills in different fields), so a lot of the information they provide is of less or no value
4. WHAT tech would love to know prior making decision is : actual reading report when it occurs (RPM, temp, V, Amps, injection time++++ = service data live stream, DTC status = history, pending or active, freeze frame data, when/how it happens...long, short rides, almost warmed up, only hot, how often...once a month... ANY modifications done to your bike ( PC, bypass O2 sensor, electronic or/and MFI related mods), any work already done to your bike in regards to this problem...
5. Would be excellent if tech has long Honda motorcycle experience and is electrically smart. Techs are people who would like to face the issue in reality, touch it, instead of having describing/filming/narrating it by members
5. Hope this RPM/stalling issue is not related to upcoming ECM update/reprogramming/recall/campaign by Japan HMC
6. If problems are not common, is more difficult to find/rectify them
7. Hope you ride your bike often , not 500 miles/year, use FI cleaner and fuel stabiliser for LONGER storage - not necessarily winter storage
8. How many members did visit HONDA or qualified service center and speak with tech personally??
9. The bottom line is (I know is not easy/simple): diagnose it right and fix it at the first time

This is NOT or about to criticize anybody's/members effort in finding problem but to provide more essential/valued technical info.
Hope this GENERAL info will help to understand the complexity in finding MFI/electrical solutions (not only TPS)

pb
 
Just pondering but... I wonder if you guys in the USA posted your ECU's to a European or Asian Honda Service centre, where they have the updated software, they could update it for you, off the bike?
Got to be worth an ask. Would love to see your problem fixed Dave. It's so frustrating seeing you having problems when there seems to be a working solution in other countries.
 
beardyweirdy@me.com_imp said:
Just pondering but... I wonder if you guys in the USA posted your ECU's to a European or Asian Honda Service centre, where they have the updated software, they could update it for you, off the bike?
Got to be worth an ask. Would love to see your problem fixed Dave. It's so frustrating seeing you having problems when there seems to be a working solution in other countries.
Click to expand...
I can kind of wrap my mind around that idea, but would you care to paint a more vidid picture? What does "posting a ECU to a service center" mean exactly?
 
pdedse, it would be the same as taking the ECU out of the bike and sending it to Don Guhl to be reflashed, except that you would send it to a Honda dealer in Europe.
 
pdedse_imp said:
beardyweirdy@me.com_imp said:
Just pondering but... I wonder if you guys in the USA posted your ECU's to a European or Asian Honda Service centre, where they have the updated software, they could update it for you, off the bike?
Got to be worth an ask. Would love to see your problem fixed Dave. It's so frustrating seeing you having problems when there seems to be a working solution in other countries.
Click to expand...
I can kind of wrap my mind around that idea, but would you care to paint a more vidid picture? What does "posting a ECU to a service center" mean exactly?
Click to expand...
I can kind of wrap my mind around that idea, but would you care to paint a more vidid picture? What does "posting a ECU to a service center" mean exactly?
It maybe that the ECU needs to be connected to the bike... This bit I'm not sure about. One we've ascertained if this is possible, or there is a work around, this is what I had in mind...

Whip the ECU off the bike:
1)Tank off, 5 mins. 10mm and 12mm sockets
2)Unplug ECU and remove, 5 mins including tea break - No tools
3)Replace Tank, 5 mins including drifting off into your own world to ponder what if....

Sending to Honda Service Centre:
4) Take ECU to Post Office/Fed Ex.
Place ECU in suitable size box, with packing and write address of Service centre on the box, or give it to the shipping clerk and inform them of the recipients address.

You'd need to contact the Service Centre first to check its ok with them before you send it, also, arranging some sort of return postage. You'll most likely need to pay them for their time and the return postage. This can be done via Pay Pal or using a Credit/Debit card via the phone or email.

I'd suggest affixing a secure label to the ECU which has your Name, Address, Tel. No. and or Email Address. Also, maybe on the rear of the ECU the year and Model of your Bike. If you can squeeze it on, possibly a note to say
"This ECU requires updating with the latest software, due to low Idle problem"

Finding a Honda Dealer that you can use may require a bit of emailing around after research on the internet or put the call out on a forum... such as this one... to see if anyone in Asia or Europe could find you a dealer to do the job. If there is a language problem, maybe the forum member could help out.

If there is a dealer out there who is prepared to do this and it works, then I'm sure it would be worth their while financially, as there are a few people in the USA who might like to get it done.

Could be worth a shot...
Note: Useful to add on the fed ex customs form that the item is for repair to avoid having it stopped in customs and an import duty being applied. UK customs are fairly keen in this regard.
 
Ah...so "post" simply means "to mail" for the British? Haha...I think at some level I knew that, but it just wan't registering.
 
The TPS on my 2014 standard is Keihin JT6H 40226.

Hi Sportster Doc. I am going back and re-reading all the trouble-shooting posts and wanted to comment on the fact that your 2014 standard TPS part number is JT6H 40226, while my 2014 Dlx part number is JT6H 40116. I wonder if this means anything (Honda upgraded the sensor at some point?).
...Then, while I was cleaning electrical connections, I remember that I was using a cheap battery from Autozone and decided to replace it with a motobatt battery. ... I waited 3000 miles to report my problem/solution just to make sure the problem was solved. I know that my case can be an isolated case but hopefully it helps someone one day. cheers.[/QUOTE]

I replaced my battery with a new YUASA battery and it did not cure the idle problem.
 
Sooooo where are we at with this? Seems like we still do not have a definite cause/cure for this problem with 70 pages and hundreds of posts?? It seems we have more bikes affected than ever (which makes sense with more bikes sold and time ridden)?
 
Dave_imp said:
The TPS on my 2014 standard is Keihin JT6H 40226.

Hi Sportster Doc. I am going back and re-reading all the trouble-shooting posts and wanted to comment on the fact that your 2014 standard TPS part number is JT6H 40226, while my 2014 Dlx part number is JT6H 40116. I wonder if this means anything (Honda upgraded the sensor at some point?).
...Then, while I was cleaning electrical connections, I remember that I was using a cheap battery from Autozone and decided to replace it with a motobatt battery. ... I waited 3000 miles to report my problem/solution just to make sure the problem was solved. I know that my case can be an isolated case but hopefully it helps someone one day. cheers.
Click to expand...

I replaced my battery with a new YUASA battery and it did not cure the idle problem.
[/QUOTE]
The Keihin JTG6 for sale on the web all have different 5 number suffixes, if the suffix is even listed.

Google 16402-RAA-A01 for Honda CR-V 2.4 liter or
16060-MBZ-A11 for 2006 Honda CB600F

At this point I do not know the significance of the suffix or if it has any significance.

AFAIK all TPS, including automotive, are powered by 5 VDC and send out ~0.5 VDC at idle and ~4.5 VDC full throttle.

The mounting slots appear the same and the connection to the throttle body shaft appears to be the same.

Your mission, should you chose to accept it, is to get suffix educated...if it matters.

Meanwhile if the electrical connector pins are all seated in each housing cavity, contact mating surfaces are clean, then electrical tests of the TPS should be done before purchasing a replacement.

Pages 5-23 thru 5-25 of the FSM cover full diagnostics, but a Honda instrument is required for some testing. Max's video will tell you a lot.
DaSwami_imp said:
Sooooo where are we at with this? Seems like we still do not have a definite cause/cure for this problem with 70 pages and hundreds of posts?? It seems we have more bikes affected than ever (which makes sense with more bikes sold and time ridden)?
Click to expand...
Max has been corresponding via PM with several posters, to gather data.

I posted a summary on Dec 27 (post 651) with earlier info in posts 615 and 618 (page 62) and 622 (page 63).

At this point, a conclusion requires test results. I continue to expect that this is not just one issue: A check for vacuum leaks and loose connections is a good start.

BTW, the Yamaha dealer found a home for my Moto Guzzi V7II.
Youngster from New York was looking for one.
It sold for what I was credited...dealer did not profit or lose...other than selling me the 2018 Yamaha XT250.

Ridden at the same speeds, my CB1100 at 1140 cc, is getting about the same MPG as the 744 cc V7 II.

On this forum, how many CB1100 have an unsolved idle?

Max, what is your tally?
 
Thanks everybody for the sympathy towards affected riders, Doc, i would conservatively estimate around 30 and counting down.

Peterbarron, well put about updating software, if anyone has seen what software looks like, its a bit like this;
------3c cf 1g bc 3d 5f----- and goes for pages, get one of these instructions wrong and you get a very expensive paperweight, and add to that the hiss system honda incorporates which made honda motorbikes theft drop to near zero and you get a better more realistic picture of the complexity and risk management of ecm control, what would you say to someone that has his ecm reflashed, installed it into his bike and now does not even cycle on startup?

another safer approach is to buy an ecm on ebay, send it over to get updated and then swap it with the original, that cost $502. for the ecu ( have a look ) but is likely not going to work because of the hiss ( i now know hiss is not applicable in the us thanks to another member but still ).

One thing that i would like to find an answer to is; the bike ran fine for a while with the current software, WHAT CHANGED ?

Compare all this to replacing a tps ( which may be the culprit in the first place, let's find out ) and the choice becomes obvious, be very careful what you advise and make responsible suggestions.

It seems a long process but a lot of factors get in the way, we have only one guy, Dave to work with and he does a stellar job at the moment, i would really like to have more participants, but apart from john ( repaired ) and pdedse ( solved by selling the bike ) none have come forward, which slows the process down.

it may be we don't find a solution but i think we will and it feels closer than ever, the trick is to just stay calm and take careful steps forward.

i really like the phrase from doc ; At this point, a conclusion requires test results.

max
 
[quote='max' pid='193069' dateline='1516478728


i really like the phrase from doc ; At this point, a conclusion requires test results.


another safer approach is to buy an ecm on ebay, send it over to get updated and then swap it with the original, that cost $502. for the ecu ( have a look ) but is likely not going to work because of the hiss ( i now know hiss is not applicable in the us thanks to another member but still ).


max
[/QUOTE]

AT LAST !!!!!ABSOLUTELY RIGHT:exclamation::exclamation::exclamation::exclamation::exclamation:

AND

Buying ECM from different sources than Honda...may not work due to VIN writing ++ more, and even if you get OEM may need to visit Honda so their tech will write in VIN & install latest update!!!!!!!!, no kidding...... I deal with this often*
If you dig, know where and how!!! or learn a hard way by spending big $$$$$$$$ or start from zero again.

* I am not associated with Honda but different/same Asian automaker since 1983

Good luck:biker:

pb
 
TPS issues are real, but usually after a long service life.
My wife had a 2008 Hyundai Santa Fe 3.3 V6 and it went into limp mode while I was driving. Top speed about 10 MPH. After restarting, it behaved normal. After it did it again, I replaced the TPS. May have only been a connection issue, especially since I routinely clean the engine.,,but it had about 120,000 miles on the odometer.

Not wanting to experience limp mode again, it was best to replace it....no tests done other than using my OBDII plug-in unit.

However, with a fairly new TPS (age or miles), with little operation to damage the internal wipers, I remain skeptical that Keihin produced very many defective units.

I have not opened one, but expect the wipers to be redundant several times over *. Failure could occur if
a. All the wipers broke or lost spring pressure
b. Resistor damaged/worn
c. A lot of crud inside.

* The industrial automation company that fed my family for decades built systems to assemble and test several automotive sensors. All the ones with moving parts for variable resistance had multiple wipers (contact fingers).

Again, since the issue is intermittent and with sensors relatively young, I would thoroughly check for good connector connections.
 
SportsterDoc_imp said:
TPS issues are real, but usually after a long service life.
My wife had a 2008 Hyundai Santa Fe 3.3 V6 and it went into limp mode while I was driving. Top speed about 10 MPH. After restarting, it behaved normal. After it did it again, I replaced the TPS. May have only been a connection issue, especially since I routinely clean the engine.,,but it had about 120,000 miles on the odometer.

Not wanting to experience limp mode again, it was best to replace it....no tests done other than using my OBDII plug-in unit.

However, with a fairly new TPS (age or miles), with little operation to damage the internal wipers, I remain skeptical that Keihin produced very many defective units.

I have not opened one, but expect the wipers to be redundant several times over *. Failure could occur if
a. All the wipers broke or lost spring pressure
b. Resistor damaged/worn
c. A lot of crud inside.

* The industrial automation company that fed my family for decades built systems to assemble and test several automotive sensors. All the ones with moving parts for variable resistance had multiple wipers (contact fingers).

Again, since the issue is intermittent and with sensors relatively young, I would thoroughly check for good connector connections.
Click to expand...
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
If you still have it????......
A good Hyundai tech and a friend of mine told me this::

Some Santa Fe with 3.3L engine may experience a MIL with the ETC (Electronic Throttle Control) system-related DTC P2135
-P2135:Throttle position sensor 1/2 voltage correlation) or P0110 or P0128 P0300 or P030X or P0638 and others.
An improved Throttle Position Sensor (TPS) and ECM software upgrade or complete updated throttle body are available to resolve this condition.

pb
 
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