Help troubleshooting low idle issue - please read and contribute
Thread Starter
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Road Master
Joined: Feb 2010
Posts: 804
Likes: 1
From: 415
Low idle issue - could use some help
My bike is idling too slowly once warmed up, stumbling, and it has stalled once so far.
Been searching and reading [1] come to understand that idle control involves a great number of sensors and components and a failure in any one of them can cause an issue which may be partially covered up by other components overcompensating.
Asking those who have been through this issue to pipe in with what eventually fixed the issue for them, and then if possible some notes on the specific symptoms they were having up until it got resolved. Idea being to help those in the future who suffer the issue to have better clues as to which of the possible components might be responsible in their case - based on the experiences of others.
Here's my general research so far. [I'll describe my personal issue below]
Common possible causes for low idle issue:
- air leaks in the intake area
- IAC motor issue
Fix 1: spray MAF sensor cleaner into the IAC
Fix 2: replace IAC motor
- idle speed sensor issue
- low voltage issue
- Fuel hoses inside tank
- software setting - ECM set for too low idle rpm target or ECM confused.
Fix: Cycle the ignition on then off at least 4 times, ten seconds per cycle. This resets the idle by forcing the computer to forget what it has learned and start over.
--- My actions so far
I've sprayed cleaner into the IAC, but turns out it was probably not the right cleaner (was carb cleaner and not MAF). it didn't seem to change the issue one way or the other. I am going to buy some MAF cleaner and try again.
I confirmed my battery terminal leads are on tight. I don't think I have a battery connection issue, but maybe there's a specific fuse with a poor connection, I have not pulled them all.
I also removed and re-seated my fuel injectors with well-oiled o-rings. This did not affect the issue either.
Bike runs great when on the throttle.
[1] See: http://www.pdf-archive.com/2011/03/1...review/page/1/
How do you check the voltages mentioned in the doc?
Been searching and reading [1] come to understand that idle control involves a great number of sensors and components and a failure in any one of them can cause an issue which may be partially covered up by other components overcompensating.
Asking those who have been through this issue to pipe in with what eventually fixed the issue for them, and then if possible some notes on the specific symptoms they were having up until it got resolved. Idea being to help those in the future who suffer the issue to have better clues as to which of the possible components might be responsible in their case - based on the experiences of others.
Here's my general research so far. [I'll describe my personal issue below]
Common possible causes for low idle issue:
- air leaks in the intake area
- IAC motor issue
Fix 1: spray MAF sensor cleaner into the IAC
Fix 2: replace IAC motor
- idle speed sensor issue
- low voltage issue
- Fuel hoses inside tank
- software setting - ECM set for too low idle rpm target or ECM confused.
Fix: Cycle the ignition on then off at least 4 times, ten seconds per cycle. This resets the idle by forcing the computer to forget what it has learned and start over.
--- My actions so far
I've sprayed cleaner into the IAC, but turns out it was probably not the right cleaner (was carb cleaner and not MAF). it didn't seem to change the issue one way or the other. I am going to buy some MAF cleaner and try again.
I confirmed my battery terminal leads are on tight. I don't think I have a battery connection issue, but maybe there's a specific fuse with a poor connection, I have not pulled them all.
I also removed and re-seated my fuel injectors with well-oiled o-rings. This did not affect the issue either.
Bike runs great when on the throttle.
[1] See: http://www.pdf-archive.com/2011/03/1...review/page/1/
How do you check the voltages mentioned in the doc?
Last edited by macnab_sf; Oct 1, 2012 at 11:53 PM.
Seasoned HDF Member
Joined: Mar 2007
Posts: 66,948
Likes: 4,573
From: TOAK western branch
The TPS is idle control only. 2 signs of failure are a high idle or when running down the road and you come to a stop it will die.
if it was your fuel line the bike would be really choppy when your riding it it would like surge.... there is a great write up on the in tank line change... i did this myself. how does the bike act while your riding it?
Ultimate HDF Member
Joined: Mar 2007
Posts: 7,465
Likes: 15
From: Corona, Ca
most likely it is your TPS, i have the low idle when coming to a stop but mine has died on me yet it will just idle real low and then slowly go back to normal..
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Thread Starter
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Road Master
Joined: Feb 2010
Posts: 804
Likes: 1
From: 415
Thanks guys. Bike runs great under throttle, only has trouble when warm at stoplights - especially if you rev the engine and release the throttle. I bought MAF sensor cleaner today, and tomorrow if that doesn't work (to clean IAC motor) will look into ordering the TPS. thanks...
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Seasoned HDF Member
Joined: Mar 2010
Posts: 38,586
Likes: 6,435
From: Honah Lee
You leave out some very important details. Miles on I assume the 2006 Dyna. Lets think simple before we go complicated. These bikes are very reliable but like weedeaters are sensitive to things .
1.Are we talking a stock bike or all kind on mods and piggyback tuners? Forget my help
2. How long has this been going on and has bike been stored. Short time and stored. Replace all gas.
3.Maybe a load of fuel stabilizer or crud. First thing to go if the filter is crudded up is idle since ECM can not keep control of idle due to low fuel injector pressure. Check is rather complicated with out gages and connectors. Doing your own work and crud in tank. Just replace filter.
4. Once you crudely spray tons of carb cleaner crudely into throttle body or IAC passage way it washes black carbon deposits up into IAC linear motor past o-rings or TPS and in just a few days both are trashed due to sticking.
5. TPS is easy check with service manual and resistance meter. IAC is easy check key on and off and watch it after you read how it works and a little spray down passage way and see it come out hole at top just behind throttle plate.It is an air way--nothing more.
6.Throttle plate stop screw is just that and should never be adjusted. With throttle plate shut it should completely shut off throttle body. The stop screw keeps plate from digging into bore but a little carbon crude should stick plate. If it ever does, open butterfly and reach in with a sprayed cloth and wipe off and the lip of the plate. Has nothing to due with idle, just sticking.
7.Replace spark plugs just for good measure.
8.Ever pressure wash it or use tons of cleaners on it. Could be a bad electrical pin connector on IAC or TPS or the IAT (intake air sensor)
9.Does your battery have 12.6volts DC
Any of that help?
1.Are we talking a stock bike or all kind on mods and piggyback tuners? Forget my help
2. How long has this been going on and has bike been stored. Short time and stored. Replace all gas.
3.Maybe a load of fuel stabilizer or crud. First thing to go if the filter is crudded up is idle since ECM can not keep control of idle due to low fuel injector pressure. Check is rather complicated with out gages and connectors. Doing your own work and crud in tank. Just replace filter.
4. Once you crudely spray tons of carb cleaner crudely into throttle body or IAC passage way it washes black carbon deposits up into IAC linear motor past o-rings or TPS and in just a few days both are trashed due to sticking.
5. TPS is easy check with service manual and resistance meter. IAC is easy check key on and off and watch it after you read how it works and a little spray down passage way and see it come out hole at top just behind throttle plate.It is an air way--nothing more.
6.Throttle plate stop screw is just that and should never be adjusted. With throttle plate shut it should completely shut off throttle body. The stop screw keeps plate from digging into bore but a little carbon crude should stick plate. If it ever does, open butterfly and reach in with a sprayed cloth and wipe off and the lip of the plate. Has nothing to due with idle, just sticking.
7.Replace spark plugs just for good measure.
8.Ever pressure wash it or use tons of cleaners on it. Could be a bad electrical pin connector on IAC or TPS or the IAT (intake air sensor)
9.Does your battery have 12.6volts DC
Any of that help?
Last edited by Jackie Paper; Oct 2, 2012 at 09:54 PM.