I have a 2017 FXDB with a Two brothers 2-1 exhaust, Arlen Ness Big Sucker and Power Commander V. Was running great but all of a sudden I’ve been experiencing an issue at idle. When I come to a stop it idle fine around 950-1000 rpms for 10-15 seconds then it will drop to around 870-890 for a second and then catch itself and go back to normal idle. Seems like it is doing a lot of hunting around. It has also died twice while slowing down to a stop. Only does this when the engine is warm.

Things I have checked so far are:

Battery
Spark plugs-new
Cleaned IAC
Different fuel
removing pcv


Any thoughts?

 

Is it the IETMS?

 

No it is disabled

 

Speed sensor might be clean but also might be faulty as it is a classic speed sensor fault
Check TPS and do check wiring in that area for any damage as I see your changed out the IAC

 

Speed sensor was clean. Not getting any other speed sensor symptoms like turn signals not cancelling or loss of speedometer.

I dont see any damaged wires in the throttle body area.

How do do I check the TPS?

 

The speed sensor may not be showing any other symptoms except the one you have and that is a problem that only another speed sensor will show you.
Been quite a few people with the exact same problem over the years that refuse to believe that the speed sensor can cause that problem until they replace it and problem solved.
TPS should be able to be checked through the Power Commander I believe you might have to look at the power commander instructions.
If you had access to a TTS or Power Vision or even a SEPST it is easy to test.

 

Since the issue only occurs when the engine is warm I didn’t think it would be the speed sensor. I’ll check the tps through the power commander and see what it comes up with.

 

It might not be the speed sensor such is the problem when these bikes don't throw codes but we know there is a problem.
TPS can also be checked with a good multimeter.

rbabos (Ron) wrote this below so don't give me credit for it

Now if I can understand my stupid sketch here , it should be like this. Set the ohm meter to the 100 scale first.
Viewing inside the opening of the tps for the plug, place the locking tab at 12 oclock position.
The two points down left and right of center should read 41
The left upper to lower should read 42 and 12 full throttle
Right upper to lower should read 12 and 42 open.
Both readings from closed throttle to open should show smooth progression without jumping.
I had my tb off when I did this, so it will be more difficult to do on the bike, but it is possible. Hope this makes sense.

 

Yea I wish it would just throw a code to point me in the right direction. I guess that would be too easy. Thanks for the info.

 

Another symptom or issue I just noticed was that when I’m at about half a tank of gas the gas range on the speedometer really starts to drop fast from there. I took her down to what the speedometer said was 10 miles left. Filled her up and she only took 3.7 gallons.. it’s a 4.7 gallon tank.