April, 2008. I bought a brand new FLSTF Fat-boy anniversary model. I put approximately 6,000 miles on it the first two years. I had the 1000 and 5000 mile service done and had “NO “issues with the bike. Early April 2010 coming back from a 80 mile ride, my engine was racing in between downshifts as I was coming to a stop sign. , I pulled over, shut down the bike and restarted it, made it another 20 miles without any other incident.
A month later on a weekend ride, as I was downshifting, coming to a red light, the idle just dropped off almost to zero, I kept turning on the throttle to keep it running, but eventually it stalled out. I restarted it but it did it again at the next stop sign, I pulled off the road, shut everything down and then restarted it and again, it was fine the rest of that day.
I took the bike to the dealer, told them the problem and that is was intermittent at best, they test drove it they said for 15 miles without incident, also they told me No trouble codes were on the computer, and unless they could get it do act up, they had no idea what was wrong.
Around June, 2010 my battery had died, I replace it and did not have any more idling issues the rest of the season, now I really thought it was all because of the battery. I also had the 10,000 mile service done in Oct. 2010.
This year I have had the problem off and on all season, what is so frustrating is I can ride it three weeks without incident and then all of a sudden it pops up again. Of the 10 times it has happened this year, it was always coming to a stop sign or red light and the idle would drop off to almost stalling, again this would only happen when the clutch was engaged to downshift or if I was completely stopped, in 1st gear and waiting for the light to change. Note ( if I would re-start the bike it would do it again at the next stop, but if I shut it all down and then re-started the bike, it would then be fine the rest of the day ). However this past weekend I was out for a ride, everything was fine for 20 miles then all of a sudden as I was accelerating from a complete stop, my idle began to race when shifting up in gears, first to second, 2nd to 3rd and so on. I stopped at the next place I could and turned everything off, then restarted the bike and again, everything was fine the rest of my 50 more mile trip.
Now you know my frustrations, does anyone have any suggestions…
Ed...

 

Hi, Ed

Here is my take on this one.
Your ECM (Engine Control Module) is having troubles determining and maintaining the Idle Position of the Throttle.
Two of the most common causes are:
1.) Unstable Vehicle Speed Signal:
- Have you observed fluctuations in the indicated Vehicle Speed in the Speedo?
- If “Yes”, then check the Speed Sensor for accumulation of shavings; then the connectors and wiring to the sensor (corrosion; wire chafing)
- If Speed Fluctuations continue then replace the Speed Sensor – it is an easy DIY thing
2.) Intermittent connection to the Idle Control Motor (or defective Idle Control Motor)
- Check the ICM connector for corrosion
- Check the pins for unseated/unlocked pin
- Check the wires to the ECM for chafing/ short to chassis

 

I would:

1. Get a battery tender installed and use it.
2. Check battery cables & ground strap
3. Check charging system
4. load test battery

Sounds like a low voltage issue to me.

 

Actually, I use a battery tender all year long.
Also, I did check the cables and ground strap.
I didn't check the charging system, but I thought that would
have been done on the 10,000 mile service...

thanks for the feedback.

 

Its not battery related. Most likely have corrosion on plug that goes into Throttle Body. Known issue and your dealer sucks as there have been numerous tech bulletins out about it. Clean the plug on left side of TB and apply slight amount of Dielectric grease. See if it stops. If not, work the list Abo posted. Especially about the Speedo. Is it ever 'off'?

 

No, I have never noticed the Speedo being off.
I will look into the Trottle body plug.

thanks...

Ed