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Update: I cleaned the electrical connection to the air temperature sensor. The connectors all looked good when I unplugged it, but I sprayed everything with electrical cleaner and blew it clean with compressed air. I started the bike with the air temperature sensor disconnected and it seemed to start and run normally, except the low/cold idle speed was lower than normal, at about 1,100 – 1,200 RPM. The engine was cold, and the outside air temperature was in the upper 50’s. I only let it run for about a minute as I blipped the throttle a few times, and the idle decreased to about 1,000 RPM before I turned it off. I disconnected a three-pole connector directly in front of the air temperature sensor connector to try an gain more room. This connector was attached to a clip on the frame and it was not coming off (my bike looks different than the middle of the three illustrations on page 5-76 of the FSM, but I believe this connector was the one in the picture with the text [3]/[4] just above it). I immediately took the bike for a test ride, going about 8 miles with a mixture of freeway and city streets, turning the engine off and restarting it twice. To my surprise the bike ran perfectly. So I took the bike for another test ride last night, this time slightly longer. The temperature was in the upper 50’s again. It started out running perfectly, but after about 10 miles the low idle condition returned. I rode home, where the engine stalled in my driveway as I gently blipped the throttle a few times. So in summary, cleaning the air temperature sensor connection did not cure the low idle problem.
I was planning to clean the connector to the MAP sensor next, but after reading the FSM to learn where it resides I have decided to skip this test because it is almost as easy to just replace the IAC valve. I’ll clean the connection to the EVAP purge valve next, but if this doesn’t work I am just going to replace the IAC valve.
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Thanks for the update, Dave.
The failsafe value for the IAT is 95F. With it unplugged that is the temperature programmed as a substitute input.
Since you do not report DTC 1-1 or 1-2 or 2-1 and since MAP failsafe is normal operation, it is not likely a MAP issue, per FSM pages 5-15 and 5-16...not that I want to discourage checking as many electrical connections as practical.
Be interesting to see inside, as far as possible, with IACV removed.
In the photo posted by Max, the port looks rather large, so I wonder how it could be blocked/partially blocked. Wonder if it is practical to run a pipe cleaner or = to the side?
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(03-15-2018, 12:04 PM)Dave_imp Wrote: Update: I cleaned the electrical connection to the air temperature sensor. The connectors all looked good when I unplugged it, but I sprayed everything with electrical cleaner and blew it clean with compressed air. I started the bike with the air temperature sensor disconnected and it seemed to start and run normally, except the low/cold idle speed was lower than normal, at about 1,100 – 1,200 RPM. The engine was cold, and the outside air temperature was in the upper 50’s. I only let it run for about a minute as I blipped the throttle a few times, and the idle decreased to about 1,000 RPM before I turned it off. I disconnected a three-pole connector directly in front of the air temperature sensor connector to try an gain more room. This connector was attached to a clip on the frame and it was not coming off (my bike looks different than the middle of the three illustrations on page 5-76 of the FSM, but I believe this connector was the one in the picture with the text [3]/[4] just above it). I immediately took the bike for a test ride, going about 8 miles with a mixture of freeway and city streets, turning the engine off and restarting it twice. To my surprise the bike ran perfectly. So I took the bike for another test ride last night, this time slightly longer. The temperature was in the upper 50’s again. It started out running perfectly, but after about 10 miles the low idle condition returned. I rode home, where the engine stalled in my driveway as I gently blipped the throttle a few times. So in summary, cleaning the air temperature sensor connection did not cure the low idle problem.
I was planning to clean the connector to the MAP sensor next, but after reading the FSM to learn where it resides I have decided to skip this test because it is almost as easy to just replace the IAC valve. I’ll clean the connection to the EVAP purge valve next, but if this doesn’t work I am just going to replace the IAC valve.
Dave I have to say I'm am quite impressed with your stick-to-it-ness at pinpointing this problem. I know you've contacted CS at Honda and didn't have much luck, but I hope at some point the step-by-step attempts could be tabulated and sent off in another letter to Honda. They should be aware of what the members here have tried to do to find a fix for your bike. Ask for a rebate of 3 or 4k$ off your next Honda purchase or something as compensation for your taking the time to solve something they should. Yes, maybe they will laugh, but maybe they will listen and do or offer ...something.
When I talked with the the Service Manager where I was thinking about taking my affected '14 standard, he bleakly pointed out with no "check engine" light occurences, that it was very possible they would need to spend hours before finding the problem area--he said they could get lucky and ID something within an hour, or they might not be able to tell me anything after 5 or 6 hours.
Back to Honda...plead with a CS rep to pass the info along to a "higher-up", ask them to wade through these pages. If I were a Honda person, and read all this, I'd say "let's offer to buy Dave's bike and find out what's going on. Then let's find a fix, and let everybody on that forum know we got this". Wishful thinking, I guess, but man would brand loyalty have meaning.
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Hear, hear, pdedse! 
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(03-10-2018, 04:14 AM)max_imp Wrote: Thanks Dave nice report, if it is not too difficult to do i wonder if you do the same thing as before by disconnecting the iacv before starting the bike ( iacv is in 1050 rpm running position when the bike is switched off ) and nursing it to warm up to the point where the rpm is stable enough and taking it for a ride to see if the idle is usable without the iacv valve connected.
In other words: because it is now fixed in one ( correct ) position it cannot change idle rpm and mess with idle speed.
Ignore the check engine light flashing.
+1 on Doc; max Hi Max, I just found your post. Absolutely, I can do this test, but one question first. If my bike is experiencing a low idle condition when I turn it off and leave it for the night, does this mean that the IACV is potentially stuck in a low idle condition? To perform your recommended test properly do I need to put the bike away for the evening while it is idling correctly, or does it matter? I can do this test tomorrow, if it's not raining (there is a 70% chance of rain tomorrow here).
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In a word; Yes.
It has to idle at 1050 rpm when stopped, when stopped it will freeze in that position and remain like that until the pump primes and the iacv does it's startup cycle.
IF the bike is in a low idle state and stopped it will also remain in this state etc.
It would be more work to start and keep going but it would prove the iacv is in the " low " position when disconnected and remain low until re-connected after the bike has been driven, either situation would be interesting to observe.
So now you have two options.
Oh and i have to say pdedse's suggestion is a stunner.
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Update: I just ordered an IACV from my local Honda dealer, and guess what - it is out of stock and on back order! Does Honda know something that they're not telling us? I believe that Doc posted this part number is used on multiple Honda models, so I find it interesting that they don't have any in stock. Any thoughts?
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(03-16-2018, 12:17 PM)Dave_imp Wrote: Update: I just ordered an IACV from my local Honda dealer, and guess what - it is out of stock and on back order! Does Honda know something that they're not telling us? I believe that Doc posted this part number is used on multiple Honda models, so I find it interesting that they don't have any in stock. Any thoughts?
You can get a genuine Honda part on line, for less and in stock:
2WheelPros backed ordered from Honda
Partzilla, 1 in stock at $87.80
https://www.partzilla.com/product/honda/16430-MFJ-D01
Babbits appears to be in-stock at $83.39 +19.95 shipping = $103.34
Bike Bandit appears to be in-stock at $95.95 + $12.95 shipping
Can you cancel from the dealer?
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I posted to this thread about a year and a half ago when my '13 experienced the low idle condition (700 rpm) for the first time on a hot summer day. Since then it had only done it one more time. Both times I turned the engine off and the idle went back to normal upon restarting.
This morning I took a cool morning ride (about 60F) to breakfast. After 5 miles on surface streets and 10 miles on the freeway at 75-80 mph I exited and noticed that it was idling at 1500 rpm. Unusual, as the bike was thoroughly warmed up. The high idle persisted through the next few traffic lights until I reached my destination. In the parking lot, I shut off the engine and restarted. The idle went back to normal and was fine on the ride home.
So now I've had both the high and low idle condition and in every case it has fixed itself by shutting off and restarting the engine. Not anywhere near as bad as others had been reporting, but something is definitely going on with the idle system.
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Flynrider thanks for posting your findings, i hope with the weather getting warmer more will let us know their experience with this enigma.
With every post we get to know more about the circumstances when they occur, i got lost in all the posts and spent some time cherry picking posts and accumulating all relevant info in one word document and make it easy to combine the content.
To date we have four confirmed successful events apart from a number of other repairs that also worked well.
The two suspects are the tps and iacv, i think we eliminated all the easy to get to parts and are down to replacing the iacv in Dave's bike, it is a bit of a task and Dave was very helpful in the diagnosis.
We may now learn more about what it is that causes this idle thing, something that remains hidden when a dealer performs the repair, but Dave has an opportunity to clear up the fog that surrounds this repair.
Because i did some tests on how the iacv works and the help of popgun we know that the iacv is a busy part, it does a lot of work around the normal idle position, because the way the software inside the ecm is written every time the throttle moves the iacv is told by the ecm to move a few steps in the same place, in anticipation of the real reason why this is the case my thinking is that some of them do not stand up to this amount of work in this spot and have difficulty moving small amounts, they are quite delicate parts operating in a hot place, but when the engine is restarted the iacv does some more traveling and is able to overcome the sticking point and temporarily behave as normal, again, just my unconfirmed speculation.
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