Dyna dying at idle
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Joined: May 2015
Posts: 71
Likes: 7
From: Northeast Georgia
To add my 2 cents I think maybe your Throttle Position Sensor may be at fault. The computer may not know when you close the throttle so it doesn't try to adjust the IAC that first time. When you start the engine the computer runs in an open loop and preset for cold start and fast idle. It bumps the IAC a bit and ignores the throttle. That's why your problem only shows up on the first stop light. Remember your TPS spends most of it's life at closed throttle and it's just a variable resistor. So just like your old stereo volume control, it can develop a dirty spot where the reading is unreliable. Remember the scratchy volume control on that stereo? Since the bike does go to fast idle then adjusts idle later I doubt the IAC is at fault or sticking.
One cheap and easy thing to try is to remove the air cleaner to expose the TPS electrical connector. Push the tab and pull it loose. Then use some Electrical Contact cleaner ONLY to clean both male and female contacts. Mate and unplug the connector a couple of times and finally plug it back in. That won't address the problem if the TPS is in fact bad but a common problem with HD FI are those electrical contacts get dirty and cause all kinds of problems.
CRC QD Electrical Contact cleaner at Home Depot works very well and is safe around plastic.
CRC QD Electrical Contact cleaner at Home Depot works very well and is safe around plastic.
Outstanding HDF Member
Joined: Dec 2012
Posts: 2,557
Likes: 235
From: Texas
Damn confusing...getting dizzy with all this this sensor, that sensor, whatever sensor controlling fuel flow...I think I will stick with a normally aspirated engine.
First rule of wrench-turning....use the right tool and KISS
First rule of wrench-turning....use the right tool and KISS
Road Captain
Joined: Jul 2008
Posts: 613
Likes: 33
From: East Alton, IL
Yeah there are a bunch of sensors and we haven't even touched on the O2 sensor in the exhaust!
But once you learn what each sensor does it becomes a lot easier. I had to learn them working on cars. I'm an old carburetor guy myself. But I love the modern FI because of how it works to constantly adjust fuel air ratio. Starts no matter what the outside temp is or how long it's been sitting, and whether I'm at Sea Level or up in a mountain it runs great.
Tourer
Joined: Jan 2011
Posts: 356
Likes: 36
From: Oklahoma
been there
OP,
I've been down this road on my 07. I took the time to check the TPS and lots of other things. I wish I had listened to my first instinct from thirty years of working on cars and replaced the IAC first. It would have saved a lot of headaches.
It took me about 1.5 beers to replace the IAC after a couple of cases of ruling out all of the other suspects.
I've been down this road on my 07. I took the time to check the TPS and lots of other things. I wish I had listened to my first instinct from thirty years of working on cars and replaced the IAC first. It would have saved a lot of headaches.
It took me about 1.5 beers to replace the IAC after a couple of cases of ruling out all of the other suspects.
Outstanding HDF Member
Joined: Aug 2012
Posts: 3,217
Likes: 90
From: Detroit
One cheap and easy thing to try is to remove the air cleaner to expose the TPS electrical connector. Push the tab and pull it loose. Then use some Electrical Contact cleaner ONLY to clean both male and female contacts. Mate and unplug the connector a couple of times and finally plug it back in. That won't address the problem if the TPS is in fact bad but a common problem with HD FI are those electrical contacts get dirty and cause all kinds of problems.
CRC QD Electrical Contact cleaner at Home Depot works very well and is safe around plastic.
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Joined: May 2015
Posts: 71
Likes: 7
From: Northeast Georgia
So the service manual says to discard the fasteners for the TPS and install new ones, but the new one doesn't come with new fasteners. Anyone know the part number for them? I can't find it anywhere.