Really high idle

Hi chief, it can be daunting to study the long thread so i try to clarify the essentials as and where needed for the newer guys.
Just hope that i don't bore the rest of the crew with repeats, appreciate all your input as usual, all the best!
 
Max, you may want to direct Gordo to your TPS tests and throttle calibration

I think you had more than item C in this post

https://cb1100forum.com/forum/showthread...20&page=66

C. Follow TPS diagnostics per pages 5-23 thru 5-25 of the FSM. Note comments in posts 615, 618 & 622, especially see Max's post 632 regarding TPS output test.

If output is not 0.5 VDC, loosen fasteners (ignition on, engine NOT running) and rotate TPS to obtain 0.5 VDC, throttle closed. After adjusting TPS throttle closed output, do a throttle calibration with ignition on, engine NOT running, by SLOWLY opening and closing throttle, 2-3 times.
Post 615 & 618
[url=https://cb1100forum.com/forum/showthread.php?tid=8120&page=62]https://cb1100forum.com/forum/showthread...20&page=62

Post 622
[url=https://cb1100forum.com/forum/showthread.php?tid=8120&page=63]https://cb1100forum.com/forum/showthread...20&page=63

Post 632
[url=https://cb1100forum.com/forum/showthread.php?tid=8120&page=64]https://cb1100forum.com/forum/showthread...20&page=64

Also check ALL vacuum hoses and Ts are intact.
 
If the piston was too far into the barrel it would re-align itself over the next few startup cycles to the position the iacv is happy with, like 2 steps forward 4 steps back, it will always find the back stop.

Interesting. If there is no feedback from the IACV to the ECU then how does the above happen? Does this mean that if Gordon accidently didn't completely thread the cylinder onto the IACV drive shaft during installation then the IACV will automatically adjust to find the back stop?
 
Hi Dave, good question, if the barrel was set too deep into the cavity the bike would not run at 1800 rpm since the opening would be restricted
( all other things being equal ).
here is the iacv body removed, look at the two openings at the bottom of the cavity and you can see the iacv piston sitting halfway the opening where he points his little finger at;
 
Just found Pavel's video and made a slow motion part of the iacv operating on a cold engine startup.
Notice the shaft spinning over 5 times more to open than to close with a cold engine,
this ensures that the iacv is at the end of the open stroke every time and the function of the friction clutch in the piston.

If you search "cb1100 iacv you will find 7 video's with info on the iacv operation;
https://www.youtube.com/results?search_query=cb1100+iacv

I keep noticing in Popgun's video with the oscilloscope that the pulses on startup are wider than during operation, my
assumption is that the energy is just sufficient to move the iacv when it is new but once exposed to heat it just loses the battle, just my 2 cents....
Hope this helps.
 
Thread starter
I am gonna tear everything back down this weekend and re check to make sure everything is lined up correctly with the iacv. I think it is, just want to make sure.

Titus 2:13
2013 HONDA CB1100
Thank you guys again for all your help! I really do appreciate it. I just tried to up load a video, but it's too large.

Titus 2:13
2013 HONDA CB1100
 
Hi Max, and all. Is it possible to disconnect the IACV from the ECU and control it manually (electronically), just to check its operation? Could this be done relatively easily? This could help determine if the IACV is moving, and possibly determine if the ECU is sending a proper signal.
 
Thread starter
I know this weekend when I had it all apart again I was checking for leaks and making sure everything was tightened down and secure. Fitting the iacv was daunting task. Trying to line it up and sliding it in. While everything was apart I tested both iacvs. I placed tape on the new iacv and left the old the same. I checked to make sure both were operating. Both iacvs reacted the same when I turned on the ignition.

Titus 2:13
2013 HONDA CB1100
Also by chance does anyone know what part or part number is the automobile equivalent of the CB1100 TPS? I am 300+ posts in on the 1237 post irregular idle thread. I recall some one mentioning there was one, but I dont recall the manufacture or part #
I would really like to test this theory because disconnecting the tps on my CB brings my idle down to 1050 rpms

Titus 2:13
2013 HONDA CB1100
 
See the post 82 links
The Honda Rune Forum has posted a TPS replacement for the Keihin JT6H TPS: 16060-MBZ-A11, $114.29 from honda. This is for a 2006 CB600F. The Rune Forum posted that this sensor is a Keihin JT6H, but we have not yet verified compatibility

Follow TPS diagnostics per pages 5-23 thru 5-25 of the FSM. Note comments in posts 615, 618 & 622, especially see Max's post 632 regarding TPS output test.

If output is not 0.5 VDC, loosen fasteners (ignition on, engine NOT running) and rotate TPS to obtain 0.5 VDC, throttle closed. After adjusting TPS throttle closed output, do a throttle calibration with ignition on, engine NOT running, by SLOWLY opening and closing throttle, 2-3 times.
 
Just to eliminate confusion, you are talking about Throttle Position Sensor (TPS) here and not Tire Pressure Sensor (TPS), right? Not trying to be funny or difficult. Thanks.
 
Yes Nacho. Throttle Position Sensor.

It is being discussed as it is not available as a separate part for our bikes.
 
Gordo before you change anything to your tps write down the voltage on the middle pin with throttle close and fully open.
Just checked mine and it reads 0,489 volts closed and 3.971 volts fully open, just like Sportsterdoc mentions.
When disconnected the red/black center wire measures 0.024 volts and the orange light blinks, don't worry about this, when the key is switched off and back on again ( with the connector back in place ) it will stay off.

The way to check this is disconnecting the connector ( much easier than having the connector connected ), inserting a test pin in the middle contact ( you can use a folded open paper clip for this ) push it in right beside the red/black wire until it stops at the contact, plug the connector back in and note down the values for later, you only get the chance once before any adjustments are made.
The tps is the electronic equivalent to a needle on the slide of a carburetor and informs the ecu what the fuel air ratio should be for each position.

More interesting is that the engine idles at 1050 rpm, if this happens with the new replaced iacv that could mean ( but not necessarily is ) that the iacv is operating which you proved by connecting it externally and it rotated as expected.

One thing to note is that one member had a high idle and he discovered that one of the contacts in the tps connector was rotated by 90 degrees, once inserted correctly the problem was solved, just something to check, he did post a very clear picture of this somewhere early in the thread.

If that is the case study how the connector itself is taken apart before damaging it trying.

And Dave, the best way to test the iacv is as shown in the video which Gordo has done, saves confusion.
 
Thread starter
Yes.. the the throttle position sensor. Sorry for the confusion.

Titus 2:13
2013 HONDA CB1100
Thanks guys I'll test it in the morning when I get home.

Titus 2:13
2013 HONDA CB1100
 
pdedse_imp said:
jwst11_imp said:
Hi,

I am from Singapore and my 2014 CB1100 EX used to have low idling problem. I have replaced the IACV using 16430-MFJ-D01 but my low idling problem came back a few weeks later. I replaced my IACV again, this time using 2017 part number 16431-MGZ-D01 and I have not encountered any low idling problem for more than a year now. Anyone know why Honda changed IACV part number from 2017 onwards when the throttle body part number remained the same for all CB1100 models?
Click to expand...
Perhaps somone more knowledgeable than I can say for sure, but I can only assume Honda changed the IACV part number because they realized the pre-'17 IACV part was susceptible to high/low idle issues, and they "tweaked" the IACV, resulting in a new part number.

Your story is good anecdotal evidence of this; you tried the fix with the 430-MFJ--it didn't work, then you installed the '17 431-MGZ and that fixed the issue. Several others (2 or 3?) on this forum have had success by replacing the IACV. It would be helpful if they could confirm that the new IACV part was used to make the high/low idle issues go away.

Dave in San Diego?
Click to expand...
Perhaps somone more knowledgeable than I can say for sure, but I can only assume Honda changed the IACV part number because they realized the pre-'17 IACV part was susceptible to high/low idle issues, and they "tweaked" the IACV, resulting in a new part number.

Your story is good anecdotal evidence of this; you tried the fix with the 430-MFJ--it didn't work, then you installed the '17 431-MGZ and that fixed the issue. Several others (2 or 3?) on this forum have had success by replacing the IACV. It would be helpful if they could confirm that the new IACV part was used to make the high/low idle issues go away.

Dave in San Diego?
I replaced it with 16430-MFJ-D01 for 2014 models, I have traveled 7,000 km and no problems have been encountered.
But they also applied the modification released by Honda at the time to the ECU.
 
I’m putting that part number in my service manual this time. Didn’t last time couldn’t find it recently and wasn’t going to read all those idle problem posts :D
 
Lord Popgun_imp said:
I’m putting that part number in my service manual this time. Didn’t last time couldn’t find it recently and wasn’t going to read all those idle problem posts :D
Click to expand...
U R high skilled tech and troubleshooter, no need to memorize or make any notes.... just straight diags;)
 
Dave in San Diego?
[/QUOTE]

I replaced my defective IACV with part number 16430-MFJ-D01. I have traveled 12,000 miles and no problems have been encountered.
 
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