Ecm Problem ?
Engine Choked!
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Ultimate HDF Member
Joined: Apr 2008
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From: Out on Deranged
Engine Choked!
This has happened twice so far.I come to a corner and the engine idles so low it sputters out.first time in june after riding the previous day for 4 hours in the rain,second time yesterday august24th no humidity sunny skies. I have to keep revving the throttle to keep it alive- turn off ign. switch,turn back on and all is fine. Should I be worried?
Warranty issues to date after six months on '08 FatBob:
forward primary rubber gasket leak
horn
porous crankcase=oil leak
front brake master cylinder fluid leak = paint peeling
battery died
All but mastr cyl (back ordered) has been addressed.
Warranty issues to date after six months on '08 FatBob:
forward primary rubber gasket leak
horn
porous crankcase=oil leak
front brake master cylinder fluid leak = paint peeling
battery died
All but mastr cyl (back ordered) has been addressed.
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Ultimate HDF Member
Joined: Apr 2008
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Likes: 12
From: Out on Deranged
actually only at stoplights so far,if I ease off real slow and gradual like it will idle low,real low,but turning off and on the ign snaps back into shape,like I said this happenedonce 2 months ago,and then yesterday,and it starts and runs fine now.
Big Kahuna HDF Member
Joined: Feb 2006
Posts: 23,881
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From: USA
+1 your idle should not fall below 900 rpm on the bike. The idle settings are programmed into the ECM map that you are running. You could have a sensor issue if it is happening while cornering I would have them check the bank angle sensor. If that checks out look at the idle air control.
Last edited by KBFXDLI; Aug 25, 2008 at 10:54 AM.
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Ultimate HDF Member
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From: Out on Deranged
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Outstanding HDF Member
Joined: Nov 2007
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From: Beautiful Downtown Burbank
Mine does it occasionally after I've been riding the freeways at sustained high rpm's. Pull off and let it come to an idle, and it lopes along like a carbed motor. It will stay loping for the first couple of signals, unless I give it 20 seconds at idle. Then the idle returns to normal, and the bike acts as if nothings wrong.
It's definitely an ECM / sensor issue, but not one that will trigger a code.
The bitch about intermittent problems is you have to wait until a code is given, or the darn part fails.
It's definitely an ECM / sensor issue, but not one that will trigger a code.
The bitch about intermittent problems is you have to wait until a code is given, or the darn part fails.
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Road Warrior
Joined: Mar 2008
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That's your IAC. When you turn off the ignition the ecm recalibrates the IAC by closing it and reopening it. So that fixes the problem. The ecm can't read the position of the IAC, but, rather, keeps track of how many steps it told it to turn. If you have a loose connection or something keeping it from always turning when the ecm tells it to then the ecm is wrong about where the IAC is positioned.
Within the throttle body there is a hole at the top before and another just after the throttle plate. That's an air passage that bypasses the throttle plate. The IAC is a stepper motor that turns a pintel restricts air flow through that passage. The ecm is able to use the IAC to produce the same effect as opening and closing the throttle plate.
The IAC is obviously working, at least most of the time. You don't have trouble with starting the bike nor idling after you start it. The IAC tracks throttle position though. So you're driving down the road opening and closing the throttle to adjust speed and the IAC is opening and closing in tandem only sometimes it's missing steps. If those were steps opening it then it keeps closing more and more as the ecm thinks the step count is higher than it actually is.
I believe the ecm can tell when the stepper hits the stop and that's how it calibrates it when you turn the bike off. Run it until it completely closes and reset the count to zero there. So if during operation the ecm detects it hit the stop then it will likely reset and return to working properly.
Overall, a new bike, not your problem, take it to the dealer and have them fix it.
Within the throttle body there is a hole at the top before and another just after the throttle plate. That's an air passage that bypasses the throttle plate. The IAC is a stepper motor that turns a pintel restricts air flow through that passage. The ecm is able to use the IAC to produce the same effect as opening and closing the throttle plate.
The IAC is obviously working, at least most of the time. You don't have trouble with starting the bike nor idling after you start it. The IAC tracks throttle position though. So you're driving down the road opening and closing the throttle to adjust speed and the IAC is opening and closing in tandem only sometimes it's missing steps. If those were steps opening it then it keeps closing more and more as the ecm thinks the step count is higher than it actually is.
I believe the ecm can tell when the stepper hits the stop and that's how it calibrates it when you turn the bike off. Run it until it completely closes and reset the count to zero there. So if during operation the ecm detects it hit the stop then it will likely reset and return to working properly.
Overall, a new bike, not your problem, take it to the dealer and have them fix it.
