High Idle...

[19DUC04]

Recently had an issue with my bike being stuck at 3000rpm, in neutral, with no hand on the throttle. It was weird. No matter what I did, the high idle would come and go randomly and we immediately ruled out that it was not a mechanical issue. Long story short, it was the TPS - throttle response sensor being out of sync. For whatever reason the TPS was adding gas when it shouldn't.

Resolve: Just in case you all run into this, turn the ignition on and off 5 times. Just switching the key back and forth 5 times forces a re-set to the TPS. Sure enough, the problem is gone and haven't had a problem since.

Hope this helps someone else out there... could save you a trip to the shop.

[nevb]

Hi
I had this problem a couple a times and after 3 or 4 rides it would not start at all. After checking the battery, the solanoid, rectfier ,I found the problem to be a rusty nut, bolt and washer on the positive wire on the starter motor .
I know it sounds totally unrelated but in genral the bike was reving in the 3000rpm and if you turn the bike off and restart it some times it would be normal and other time high rpms again.
My guess is that the high resistance joint created a big load on the battery reducing the voltage to the ecu so it was not initializing properly on start up.
Cheers
Nev

[Tom S.]

Originally Posted by 19DUC04

...
Resolve: Just in case you all run into this, turn the ignition on and off 5 times. Just switching the key back and forth 5 times forces a re-set to the TPS. Sure enough, the problem is gone and haven't had a problem since.

Hope this helps someone else out there... could save you a trip to the shop.

Thanks for the tip. Five times on and off. That's one to write down and stick somewhere on the bike. None of my bikes w/carbs do this. Modern times....

[YellowDuck]

Not trying to start an argument about this, but I am having a hard time believing it. Not saying it's for sure not true, but here is my reasoning:

1. Like many here I have been reading *piles* about the fuel systems in these bikes for the last 5 years, and I have never come across a protocol for resetting the TPS with the ignition key. Why are we just leaning this now? I always understood that a Mathesis, VDST or similar was needed to do this. It seems unlikely that there was a DIY protocol available all the time and no one knew about it.

2. Adding gas at closed throttle would not normally result in a high idle, would it? I would expect the opposite. Usually at closed throttle you need to lean out the mixture (e.g., by opening the air bleeds) to raise the idle speed. It's hard (at least for me) to imagine a TPS error that would increase the idle speed.

Again, not saying I know everything there is to know about this (not by a long stretch), but I would need a bit more info to be convinced that what was posted here is actually correct.

There is a servo motor that adjusts idle speed by controlling a throttle air bypass circuit and adding fuel accordingly, so it's possible this was involved. That system can only increase the idle speed, not reduce it. In my (admittedly limited) experience, when you have a high idle condition on these bikes and the air bleeds are already totally closed, your only recourse is to adjust the idle fuel trim to make it a bit richer. Again, this requires a computer to talk to the ECU.

Just my two cents - I am happy to be proven wrong.

[19DUC04]

YellowDuck,

I here you. At first it sounded funny to me as well. However and per the Service Manager, this is what they did. He did mentioned that there was an issue just like this recently and this was also the resolve. To my understanding and at closed throttle, the TPS - which is similar to an electronic choke - was over compensating and adding fuel when it was not suppose to. By re-setting it through the little trick, it went back to the "stock" setting. I may be explaining wrong but have had no issue with my bike since - unexplainable.

Could it be like some vehicles with the check engine light? Press brake pedal 5 times and turn car off a few times and check engine light goes away?

I appreciate the feedback...

[YellowDuck]

The TPS is not really like an electronic choke. It is the Throttle Position Sensor - it tells the ECU what the throttle plate angle is. You normally only do a TPS reset when you change the ECU or change the TPS, to "teach" the ECU what the signal is when the throttle is at its "closed" position (which is actually open a few degrees but I can't remember the exact number).

What *is* kind of like an electronic choke is the lambda sensor. It measures the exhaust mixture and, if it is too rich, tells the ECU to lean it out. I think on our bikes this is a "learning process", rather than a real time adjustment. So, the ECU makes changes to the low rpm fueling map based on the lambda sensor output over a fairly long period of time. Perhaps your reset procedure was actually to reset that sensor-based adjustment back to the factory default setting? That would definitely cause an immediate change to the low rpm fueling.

I have never heard of that procedure before either, but it makes more sense than a TPS reset. And, it is only relevant if you have the stock ECU - the DP ECU does not use the lambda signal.

I'd be curious to hear if anyone else knows something about this!

[bpreynolds]

Wow. My bike has been doing the high idle thing for the longest time. I had just basically assumed the bike was enriching the fuel mixture due to a cold engine - this because the high idle always went away after about 4-6 miles of riding.

[efiniGTX]

Originally Posted by 19DUC04

YellowDuck,

I here you. At first it sounded funny to me as well. However and per the Service Manager, this is what they did. He did mentioned that there was an issue just like this recently and this was also the resolve. To my understanding and at closed throttle, the TPS - which is similar to an electronic choke - was over compensating and adding fuel when it was not suppose to. By re-setting it through the little trick, it went back to the "stock" setting. I may be explaining wrong but have had no issue with my bike since - unexplainable.

Could it be like some vehicles with the check engine light? Press brake pedal 5 times and turn car off a few times and check engine light goes away?

I appreciate the feedback...

The pedal trick pertains to BMW's, and it doesn't actually turn off the light but puts the DME or ecu into diagnostic mode so that the cluster can display a code. I think it is more likely that the key on/off 5 times puts the ecu into diag mode rather than actually resetting it. When I worked at a car dealer the dealer scanner did have a TPS calibration mode, but not cycling the key.

[rotten]

Well I gave this a go to fix my eradic idle problem - it worked, problem solved! Thanks for sharing this.