Idle Hang

dear all,

Ive been reading through the site but not sure I can find the info I need.

my 2018 R3T is getting the idle hanging at 12-1300rpm for anything up to 20 seconds when coming to a stop before dropping to the normal 850 rpm. It seems to be more likely to do it when cold and less likely after riding for a while. Not sure what’s happening? Is this a TPS issue, a tune issue? Or something else?

Sounds like the TPS, had similar happen to mine just before last service, in my case it was just a matter of a clean and lube of all the linkages and that fixed it

Mike188 said:

Sounds like the TPS, had similar happen to mine just before last service, in my case it was just a matter of a clean and lube of all the linkages and that fixed it

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+1. After three TPS changes and all the lubing stuff, mine was finally fixed by removing the stepper motor action arm. The motor is electrically connected by not mechanically. Throttle butterflies were removed.

2018? Have you verified the gap on the stepper motor for proper adjustment? But if its in adjustment buy both, stepper and tps and be done with it for 2 or 3 years. Or lube adjust clean and maybe go for 2 or 3 weeks or months. if in fact you still have your stepper look in the book and verify that it does indeed have correct gap on wheel and moving freely when ignition goes on, just watch it. id just buy both and no dicking around, you can also check to see how tps is functioning in tune ecu, volts are shown and tp throughout range, my stepper motor also is in the drawer, and also no hiccups since placing in drawer, like what youre having now, that if i was to just guess, its that thang that i keep in the drawer now also.

I’m not in a hurry to replace all the parts if I don’t have to as it’s over $400 in parts. Not sure I quite get how I can just remove it? What does it actually do? Doesn’t it control idle?

is it possible that a power commander autotune could cause these types of issues or an issue with fueling tables? Interestingly when I wiped the fueling table in PCv and did a a reset adaption in tune ecu the bike just fired up at correct idle?

I will be checking adjustment of tps and stepper motor on the weekend when I have more time but I’ve also lubricated all the linkages in the meantime....

Very possibly could be that. sometimes resetting is the advice given to see if that fixes issues. did you check stepper or tps?

Kevin frazier said:

Very possibly could be that. sometimes resetting is the advice given to see if that fixes issues. did you check stepper or tps?

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Not yet... need a little more time so will do this weekend... unfortunately work takes up about 60hrs a week

The stepper motor (primary) looks after your idle speed based on the input from the ECM which gets it's info from the TPS, MAP and several other sensors. With the stepper motor in place, your throttle doesn't park on a throttle stop screw but on the stepper motor which gives you a fast idle on start up and relatively steady idle speed around 900 rpms once warmed up. It will also try and maintain that idle speed when a slight load is sensed, say when in gear idling around without you opening the throttle. It is an electronic idle control servo trying to maintain a constant engine speed depending on engine temp. With it removed, you will have to set the throttle stop screw to the idle you want. You will also have to hold your throttle a bit when cold since the electronic fast idle isn't available.

I'm guessing the problem is either the TPS or Stepper motor with the TPS being the most probable item. Many more TPS sensors replaced than Stepper motors. The TPS can be checked with a voltmeter or an ohmmeter. Check YouTube for numerous ways to do this. Pretty well the same test procedure for most vehicles/cars.

So, as an update. I did the TPS and ISCV adjustment for the first time since the bike was new. Was well out like .54 and .68 It is now sitting on .618 for TPS and .718 for ISCV. I may still buy a new TPS to have on hand as I’m guessing


The engine now idles at 850rpm even when cold on startup and no more surging today when I rode for the first time since doing it. The bike has always idled high on startup initially like at 1200rpm then settled down, now it just idles at 850 straight away.... so I guess it was never properly adjusted? seems to be a theme with this bike....