Strange symptom of fast tickover and refusal to shut down revs

[viewdvb]

Had a strange experience today. Started my S10 from cold and the revs zoomed to 3-4000 and wouldn't decrease. As the engine warmed the revs dropped to just above 2000 but wouldn't drop to normal tickover. Checked for tight throttle cable and other usual suspects but the problem was NOT mechanical. I switched the engine off, immediately re-started it and tickover and everything else was normal. Obviously an electronics glitch. It has not recurred since but it woulkdn't be nice if it happened when riding. Anybody any ideas or experiences?

 

[Koinz]

A couple of people here experienced something similar. Something to do with the wiring for the throttle bodies being effected by stator interference. Move the wires away from the stator apparently resolves the issue. 8)

Here's a quote from another person that had the problem. Do a search here for "high idle"

"I had did a follow-up PM exchange with the OP a couple of months ago, and he said the problem is gone after he moved some wires. He discovered the power output wires coming from the stator were too close to either the TPS wires or the throttle servo motor wires...(I don't remember which). Now that he has separated those wires, the problem is gone. "

 

[snakebitten]

We go years without anything but spokes and headlight harnesses. (And, the hard start, of course)
Nothing else but a few one-offs.

Suddenly several bikes pop up with this crazy idle issue. And all at once. Kinda eerie.

 

[viewdvb]

Thanks for the input Koinz. That gives me some avenues to explore. Whether it cures the problem or not, it will do no harm to check the wires and re-route as appropriate.

 

[spasm]

Mines just started doing this today, the engines idling at 3k I've just had the tank off checked all cables, sprayed everything and it's still doing it, I'm sposed to be going away on Friday on it. Desperately need a solution :-\

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[spasm]

I've sorted it

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[snakebitten]

Inquiring minds want to know.

 

[fedev2]

I've sorted it

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so have you solved it?

 

[viewdvb]

I've sorted it

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Yes but what did you do to sort it?

 

[fedev2]

I've been re-routing some wiring and since then the bike I've done 1000 km without issues.

 

[Koinz]

I've been re-routing some wiring and since then the bike I've done 1000 km without issues.

Glad you sorted it out and it's good to know that this isn't a failure of a part of some sort. If you don't mind, could you share any more details around what wires were moved to remedy the problem in case others run into the same issue?

Thanks in Advance

 

[fedev2]

Koinz, the failure disappeared when the Joint Coupler wires were untied, and spread out, also all contactors and plugs were checked and cleaned, but I think its to early to say ITS SOLVED since its a very sporadic failure, once I've been riding 2 weeks and almost 8000km without issues and the following day the bike started to fail again, revving up to 3000 rpm by itself without rider inputs and stalling at traffic lights, also code 60 was displayed on some ocasions (that was checked and everything was ok no servo motor problem detected).
In my opinion is a wiring problem, a false contact or a short circuit or even an electromagnetic interference. I found the relation of the problem with these (joint coupler) wires by just touching them, take out the crash bars (if any), remove the fairing of the right side, and move the joint couple wires, bike should rev it up to 3000 or 4000 rpm also a very rough idle will appear (800 rpm in my case) and keep moving the wiring laterally in and out and bike will stall.
Since the re-routing it's been 1 week and 1100 km without failures.

NOTE: the Joint coupler is the one below the Main Fuse, usually Gray colour, and at least in my bike its wiring were routed to the outside, keeping the other wires to the internal part of the bike.

I hope it hepls the others to find a solution, since this problem became popular recently. Sorry for the bad english spelling, and start touching the wiring IMO the problem is right there.

 

[Koinz]

Koinz, the failure disappeared when the Joint Coupler wires were untied, and spread out, also all contactors and plugs were checked and cleaned, but I think its to early to say ITS SOLVED since its a very sporadic failure, once I've been riding 2 weeks and almost 8000km without issues and the following day the bike started to fail again, revving up to 3000 rpm by itself without rider inputs and stalling at traffic lights, also code 60 was displayed on some ocasions (that was checked and everything was ok no servo motor problem detected).
In my opinion is a wiring problem, a false contact or a short circuit or even an electromagnetic interference. I found the relation of the problem with these (joint coupler) wires by just touching them, take out the crash bars (if any), remove the fairing of the right side, and move the joint couple wires, bike should rev it up to 3000 or 4000 rpm also a very rough idle will appear (800 rpm in my case) and keep moving the wiring laterally in and out and bike will stall.
Since the re-routing it's been 1 week and 1100 km without failures.

NOTE: the Joint coupler is the one below the Main Fuse, usually Gray colour, and at least in my bike its wiring were routed to the outside, keeping the other wires to the internal part of the bike.

I hope it hepls the others to find a solution, since this problem became popular recently. Sorry for the bad english spelling, and start touching the wiring IMO the problem is right there.

Thanks Fedev, hope it stays fixed for you.

 

[snakebitten]

Fantastic post. Spelling is fine. You are a true gent for passing it on.
Thanks.

 

[fedev2]

Well more news coming this afternoon, this holy bike was running fine, I stopped a few moments on a local market and at the moment of starting the bike again it had a very hard start, solved by opening the thottle a little bit, idle went down to 800 rpm but apart from that there was nothing anormal, no hung high revs, nor stalling at traffic lights, I did a few blocks back to my home and shut it down, wait a few seconds and the failure was gone completely, again the bike running flawless. Since I could not believe its was everything normal I took her for a longer ride, 40 km with open roads, slow traffic, and also shut it down and started it again a couple of times.
I dont know if someone made a voodoo on my bike or what but this "ghost" that comes on and off in such a sporadic way, so unpredictable, makes me wonder a lot about buying a ST again. I really love this bike, I've had a ST 750 '92 (best bike ever no problems white, purple & pink A BEAUTY), and I'm a Yamaha enthusiastic but what a disgrace with this bike!. I know beemers have problems too I've read something about "engine change" on the new 1200GS LC, I thought the word "problem" was related to BMWs, maybe I was wrong.
Well, I think I'll be writing more pages on this neverending? story, playing Hide & Seek with my Nemesis the f....cking wiring.
Nothing more to say, have a good night!