CB1100 Idle speed instability problem

[max]

Hmmm, this guy has a video in three parts where he cleans his tps.

The symptoms sound the same as ours, slightly long winded but has some interesting tricks in it probably worth a look;

https://www.youtube.com/watch?v=IuuSlyAyO2M

also has some good comments from other owners.

Thanks for keeping an eye out for this issue,Riko, as far as i can see your new throttle body has only 2 parts in it that are electronic controls; the tps and the iacv, kinda makes an easy choice.

The tps adjustment is kinda critical and may be the reason why they sell them as a unit to save on labor and mistakes made by undertrained mechanics.

by the way, a tps is exactly the same as a volume control on your radio, a variable resistor, and remember when it crackles if the volume changes?

cheers max

[SportsterDoc]

The three part video is 10 minutes + 10 minutes + 8 minutes, 48 seconds.
Part two shows the “cleaning”.

There is risk, since contact cleaner may dislodge particles, but might not completely remove particles…which may be a future problem. If “cleaning” worsens the issue, there is more risk, since the TPS is not available without purchasing the entire throttle body assembly. For automotive applications, replacement is standard procedure.

OTOH, contact cleaner and filtered compressed air in a can have helped maintain 1973 and 1977 travel trailers at my ranch. If the TPS is to be cleaned, perhaps alternate contact cleaner with filtered compressed air, two or three times.

Keep in mind that the video is of a Yamaha, so diagnostics are not applicable and access on our CB1100s is VERY easy. The only complication on mine would be removing the white paint indicating that fastener torque was checked. There is so much paint, that I cannot see if it is Allen or Torx (the Yamaha was T25 security Torx).

The bottom line, at this point, is that if there is no vacuum loss, if there are no codes (such as DTC 8-1, 8-2), the IAC and/or TPS functions are suspect and cleaning may solve the problem.

[max]

Got a call from Honda Customer Service today! To refresh: back in late October or early November--I can't remember which--I took my bike to the dealer with letter in hand explaining the problem, but couldn't get the bike to "act up", so I decided against leaving bike with them. A few days later, talked to the SM who said without any check engine light and unable to duplicate the high/low idle issue, that it likely would be difficult for them to diagnose. He suggested I write my letter to Honda CS which I did and left a phone message about two weeks ago.

Back to my call: they wanted to know if I had the dealer look at the problem. I said "no" for the reasons stated above. We talked a good 20 minutes about the problem, the forum responses here, I mentioned a few specific cases. She said for anything to happen, the bike will need to be looked at by a dealer. No promises can be made, but she offered the hope that Honda will respond at times even when bikes are out of warranty. But, I need to the bike to break bad. Last 4 rides of 1-2 hrs riding, no real problem with idle, except just a dip below to 800-900 for a minute. Turn off engine, restart and all good. Nothing like before. But temps are down to 35-50 degrees, so that may play a part.

I asked about Service Bulletins and Recalls, of course nothing, but that she said they need to hear from owners with the problem. The answer is going to be contact dealer, but at least it will be better documented. In time, maybe that produces a response from Honda.

I told her that based on what my dealer said--that they need to replicate the problem--maybe when it warms up--I'll give them one go at it to see if they can determine anything. Anyway...at least they called as a result of me sending in my letter.

I encourage anyone experiencing the problem to do so.

as I said 2 pages back in this highly chaotic thread:

Many views, some comments about bad fuel, nonsense in my country, only one solution, a whole trottle body replacement, under the second hand warranty, wich is one year in Belgium.




So I'm lucky that the issue exposed itself during that period.
Since the replacement back in June '16, the idle has been rock solid in all seasons and all conditions.

My dealer told me the procedure is that they inform Honda of a issue that could potentially lead to a recall after an investigation of the 'faulty' parts.
Thats why the dealer has to hold the parts for a certain period in wich Honda can investigate.

All this time I haven't heard anything from my dealer...either they didn't pick it up or if they did, they did't deem it worthy for a general or regional recall.

They replaced my throttle body on advice from a Honda dealer in The Netherlands wich applied the same method to cure the issue....

why don't all you guys use that video as a reference?
I made it as proof to show to my dealer, because in at the end of the day you can explain as much as you like in very clear words, if he can't see it, he can't judge about it.
And showing a forum thread of 52 pages...you can predict it aint gonna be read, nor should he.

Just show you dealer the video, its made for that reason, it helped me, so why not all the affected owners here, I think I've posted my video here about 3-4 times.

When looking at youtube and cannot see another similar video of the issue, so I am beginning to think that the issue isn't as wide spread as we might think.
As I also said, many pages before, we have no idea what so ever about the share of affected bikes against the total units sold worldwide...

I've done my share, by bringing it to the dealer, informing him about the issue so that he can inform Honda about the issue.
So far, Honda hasn't collected the affected parts of my bike for investigation nor has there been a recall for it, so for all that matters, we might actually be a minority.

as I said 2 pages back in this highly chaotic thread:

Many views, some comments about bad fuel, nonsense in my country, only one solution, a whole trottle body replacement, under the second hand warranty, wich is one year in Belgium.




So I'm lucky that the issue exposed itself during that period.
Since the replacement back in June '16, the idle has been rock solid in all seasons and all conditions.

My dealer told me the procedure is that they inform Honda of a issue that could potentially lead to a recall after an investigation of the 'faulty' parts.
Thats why the dealer has to hold the parts for a certain period in wich Honda can investigate.

All this time I haven't heard anything from my dealer...either they didn't pick it up or if they did, they did't deem it worthy for a general or regional recall.

They replaced my throttle body on advice from a Honda dealer in The Netherlands wich applied the same method to cure the issue....

why don't all you guys use that video as a reference?
I made it as proof to show to my dealer, because in at the end of the day you can explain as much as you like in very clear words, if he can't see it, he can't judge about it.
And showing a forum thread of 52 pages...you can predict it aint gonna be read, nor should he.

Just show you dealer the video, its made for that reason, it helped me, so why not all the affected owners here, I think I've posted my video here about 3-4 times.

When looking at youtube and cannot see another similar video of the issue, so I am beginning to think that the issue isn't as wide spread as we might think.
As I also said, many pages before, we have no idea what so ever about the share of affected bikes against the total units sold worldwide...

I've done my share, by bringing it to the dealer, informing him about the issue so that he can inform Honda about the issue.
So far, Honda hasn't collected the affected parts of my bike for investigation nor has there been a recall for it, so for all that matters, we might actually be a minority.
Riko, thanks for your continuing efforts on this subject, at the risk of asking the obvious, can you confirm;
1 your idle issue has been completely solved for about a year( and hopefully forever) ? and
2 you have your throttle old throttle body available to you?

cheers max

[Riko_imp]

no prob

To answer your questions, no, no issues what so ever, runs and idles 100% perfectly.
All season rider here and been riding much longer with the new parts than with the old.
Bike has now around 22486km, bought it with 2000km and the issue started around 7400km, so been riding troublefree for 15000km with the new parts.

The replaced parts were kept for investigation and destroyed afterwards, so I don't have them and neither should the dealer.

[SportsterDoc]

It may be significant that there are codes for MAP, EOT, TPS, IAT, rear wheel speed sensor, each of the 4 injectors and O2...but not IACV, other than poor connection (DTC 29-1) for symptoms of "engine stalls, hard to start, rough idling".

The IACV is stepper motor operated.

A stepper receives pulses to drive to a programmed position, but provides no feedback to the ECM, for the ECM to know if the position was achieved or not...unlike a servo with an encoder.

I would expect carbon build-up may be a problem with the IACV...more on vehicles used mainly for short trips.

Popgun has a plausible theory about warping in the plastic intake manifold affecting IACV travel.

So, if visual inspection for vacuumn leaks and propane test are negative, no TPS codes 8-1 or 8-2, I would first suspect the IACV and clean it...replace if motor not operating. If no joy, then clean or replace TPS, if available.

I expect that Max was hoping Riko in Belgium had a likely defective TPS to compare with a known good unit or measure resistance per step 3 of FSM page 5-25 at 0.5 to 1.5 Kohms.

Also, since Riko's problem seems to be solved by a new throttle body assembly, which would likely have included a new IACV and a new TPS, we cannot know which one was the issue (or if a vacuum leak contributed), however, cycling the run/stop (kill) switch does cycle the IACV (FSM 5-74) and got it running after the video-documented stall and difficult restart. This may point to the IACV, as well as keeping the TPS as a suspect.

This also does not rule out an EOT issue for some forum members, but that sensor is easy to check (2.4-2.9 K ohms at 20C/68F).

These are basic TPS checks condensed from FSM 5-23 and 5-24 (no Honda MCS diagnostic instrument needed):

DTC 8-1 TP (Throttle Position) sensor low voltage
With ignition switch on and stop/run on, probe sensor contacts to verify steady voltage increase from throttle fully closed to throttle fully open.
With ignition switch off, disconnect the connector, then with ignition switch on and stop/run on, measure voltage between connector pins black/yellow (+) to black/green (-) for 4.75 to 5.25 vdc.
If no voltage, with ignition off, check continuity on black/yellow to ECM connector, for continuity of center pin sensor output black/red wire to ECM connector and for no continuity (infinity) of black/red wire to ground.

DTC 8-2 TP (Throttle Position) sensor high voltage
With ignition switch off, disconnect the connector, measure sensor resistance between black/red and black green of 0.5 to 1.5 K ohms. Then with ignition switch on and stop/run on, measure voltage between connector pins black/yellow (+) to black/green (-) for 4.75 to 5.25 vdc.

[max]

Riko, thanks again for your help, having looked at all the clues we have up to this point my suspicion is that we are looking at a tps fault that creeps in over time in a small batch of bikes.

It explains why it takes some time before the fault appears and slowly gets worse.
It explains why it sometimes initiates after driving in a hot situation.
It explains why a wot reset works but only very briefly.
It explains why the kill switch reset works but only briefly.
The bad spot is still there and wears out more over time.

It may be that honda has difficulty finding the fault because their sensors give very little problems due to good engineering ( speculation ) and are not familiar with the problem.

The next problem is the diagnosis itself, even a technician with an oscilloscope would have difficulty finding the bad spot on the sensor, let alone a digital multimeter for this purpose, and because the sensor still reads mostly ok there is no fault code, the ecu does not look for a spotty reading, it only registers very low or high ( wiper broken ) voltage before it sets a code.

So the replacement of the tps or the body and do an a-b comparison is the best test i can come up with so far.

cheers max

[SportsterDoc]

Max: Good observations and conclusions in your post 616.
When the TPS is suspect, it can be checked on the bike, key on, run/stop on, probing for a steady increase in voltage from throttle closed to throttle wide open.
It can also be checked for resistance, when disconnected.
See FSM page 5-23.

However, I am still inclined to conclude that idle instability has more than one cause, so that the IACV and a vacuum leak should be checked, especially when there is no DTC.

Thus, we have leave hope for future issues, in that a new throttle body assembly may not be the only possible solution.

For TPS failure, when cleaning is not a solution, how do we lobby Honda to provide a TPS, separate from the throttle body assembly?

The TPS on my 2014 standard is Keihin JT6H 40226.

[SportsterDoc]

More TPS basics:
The slots for the two mounting fasteners allow initial calibration when replacing a TPS.
With ignition on, stop/run on, the center position pin (black/red wire) probed with voltmeter + lead, with - lead connected to ground, voltage at closed throttle should be 0.5 vdc. If not, rotate unit to read 0.5 vdc. The reading then should be 4.5 vdc at WOT (wide open throttle).

Opening throttle slowly should result in a smooth voltage increase from closed to WOT.

[Lord Popgun]

For those following this, there is a fair amount of discussion going on behind the sceens between me, Max, and Sportsterdoc. Doc is (mostly) taking the lead here.

We also have found that the Honda Rune has some problem they call BBS and a TPS fixes it. Does anyone know what BBS is? Their board is pretty limited unless, apparently, you join and the BBS stuff is on the “tech board” which I can’t even see.

They found a replacements for the TPS and we are trying to locate a source for us here. We’re working on it.

[SportsterDoc]

The Keihin JT6H throttle position sensor is available on-line.
It has been suggested that the second line of numbers (40226 on mine) may be a batch number or mold number or serial number.

A typical TPS uses 5 vdc input, outputs 0.5 vdc throttle closed and 4.5 vdc WOT. So, it is possible (likely?) that any JT6H will work, if the mounting, mating and connector is the same.

There are many sources on-line. However, my concern is manufacturing standards, as well as seeing photos showing signs of the supposedly new unit having been mounted.

Are these truly new or did they not meet OEM specs and are "seconds"?

Until one is purchased and tested, this is not a recommended source.

https://www.aliexpress.com/item/Auto-Par...77267.html

Just advising current research...preferably a source from Japan or affiliated with Honda...ideally from Honda direct.

Meanwhile, for anyone currently having an idle issue, please advise TPS voltage readings. A safety pin (sharp, easy to push and easy to pull out) makes a good probe into the connector middle position...or to penetrate the black/red middle wire near the connector (hole can be sealed with silicone).

1600 miles on my 2014 standard since Nov 7.