Funky idle all of a sudden....

[CROSSBOLT]

Had a couple of hard starts, unexplained. Then yesterday and today had the idle go to 2600 rpm then slow down to about 1800, THEN start surging to 2600 rpm and back to 1800-2000 rpm. The fix was not the TPS (throttle position sensor) but to reset TPS and ISC (idle speed control or air bypass valve):

Key off, start-run switch on
Open throttle full and hold
Key on for 8 seconds
Close throttle
Key off

This initializes TPS and ISC and the problem went away. Normal idle 1650-1800 rpm and no surging. I don't know what the cause was other than guessing TPS "changed" a little with use.

Karl

[moparkid]

Hey Karl.....how are you liking that new DT300? I just got one yesterday and having had a Honda 150 Elite for 20 years it feels like a totally different animal all together going from that to a Kymco DT300. I almost pulled the trigger on a Honda Silverwing but at the last moment I decided to try a new Kymco over a 2008 SilverWing. Hope my faith in something "other" than a Honda will be rewarded.

[racewalker]

30,000 on mine and loving it. My second Kymco. Unfortunately we are still knee deep in snow here so can't get it out of the shed yet.

[moparkid]

Thats a bummer Sir.....here in Texas we pretty much ride year round, but of course for me when it gets below 45, I'm taking the car...lol. Glad to hear you have 30000 on your Kymco.

[Vivo]

Had a couple of hard starts, unexplained. Then yesterday and today had the idle go to 2600 rpm then slow down to about 1800, THEN start surging to 2600 rpm and back to 1800-2000 rpm. The fix was not the TPS (throttle position sensor) but to reset TPS and ISC (idle speed control or air bypass valve):

Key off, start-run switch on
Open throttle full and hold
Key on for 8 seconds
Close throttle
Key off

This initializes TPS and ISC and the problem went away. Normal idle 1650-1800 rpm and no surging. I don't know what the cause was other than guessing TPS "changed" a little with use.

Karl

Karl, the causes are vibration, heat, and moisture... these are the enemies of the TPS.... what you did was manual recalibration and that solution is usually temporary.... the mere fact that your TPS has gone to this stage is a sign that it's failing..... better anticipate a repeat of this... and be ready with a new TPS... 

[CROSSBOLT]

Vivo, you may be on to something! This has less than 1000 miles so it is disconcerting. Mopar, I love this machine! It is Kymco #3, starting with an Agility 50, then the wonderful Yager for 18000 trouble free miles and now this smooth, powerful cruiser! It should be a long-winded ride!

Karl

[Vivo]

Karl, doesn't matter if it's new or old... parts break... just don't know if your tps is the contact type or non-contact type.... did you say Mopar? We had a '70 Challenger back then... blue with black stripe, black vinyl top...I think the engine was a 383ci....had to let it go when the oil crisis hit....