Sun Sep 01, 2019 3:02 am

Molto Verboso
GTS 300ie Touring 2013 - Signora D'argento & GTS 300ie HPE 2022 - Regina Arancione.
Joined: 03 Jun 2018
Posts: 1577
Location: Lancaster, U.K.
 
Molto Verboso
GTS 300ie Touring 2013 - Signora D'argento & GTS 300ie HPE 2022 - Regina Arancione.
Joined: 03 Jun 2018
Posts: 1577
Location: Lancaster, U.K.
Sun Sep 01, 2019 3:02 am linkquote
Occasionally, when decelerating, when I've rolled off the throttle and the clutch dis-engages (effectively free wheeling) the engine wants to stall and sometimes does. The slightest turn of the throttle stops this, and the engine idle at tick over sounds normal.

There is very slight play in the throttle handle, would a little tightening of the throttle cable stop this?

Last edited by Touring300 on Tue Jun 21, 2022 8:28 am; edited 1 time in total
Sun Sep 01, 2019 5:10 am

Veni, Vidi, Posti
2007 LX150 2015 GTS 2013 BV 350
Joined: 13 Sep 2012
Posts: 10668
Location: Fond du Lac, Wisconsin
 
Veni, Vidi, Posti
2007 LX150 2015 GTS 2013 BV 350
Joined: 13 Sep 2012
Posts: 10668
Location: Fond du Lac, Wisconsin
Sun Sep 01, 2019 5:10 am linkquote
Doesn't sound normal to me.

I can't see where any mechanical adjustment at the throttle would matter.
Sun Sep 01, 2019 6:20 am

Ossessionato
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
Joined: 11 Jun 2011
Posts: 3766
Location: East Anglia, UK
 
Ossessionato
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
Joined: 11 Jun 2011
Posts: 3766
Location: East Anglia, UK
Sun Sep 01, 2019 6:20 am linkquote
Is your engine at full working temperature ie: you've ridden it at least 5 miles or more?

If it is at normal working temperature it shouldn't stall but occasionally the engine management system (automatic idle control) can be slow to do it's job, allowing the engine revs to drop a bit more than usual before suddenly normalising. That is kinda normal as long as it's not stalling. Just about all the GTS bikes from 2014 onwards seem to do this. My GTS300 engine idle revs drop dramatically sometimes when I'm in traffic usually when the engine is very hot, and the engine goes to idle after the clutch disengages, but this normally only happens when the engine cooling fan is on in traffic. This loads the engine more than usual, but mine has never stalled.
Sun Sep 01, 2019 6:53 am

Veni, Vidi, Posti
In garage: Yamaha Tricity 155 Urban 2019 - MV Agusta 125 RS 1956
Joined: 21 Jul 2007
Posts: 8291
Location: Latina (Italy)
 
Veni, Vidi, Posti
In garage: Yamaha Tricity 155 Urban 2019 - MV Agusta 125 RS 1956
Joined: 21 Jul 2007
Posts: 8291
Location: Latina (Italy)
Sun Sep 01, 2019 6:53 am linkquote
Even the dirty air filter can cause the engine to shut down at idle ...
Sun Sep 01, 2019 7:17 am

Molto Verboso
GTS 300ie Touring 2013 - Signora D'argento & GTS 300ie HPE 2022 - Regina Arancione.
Joined: 03 Jun 2018
Posts: 1577
Location: Lancaster, U.K.
 
Molto Verboso
GTS 300ie Touring 2013 - Signora D'argento & GTS 300ie HPE 2022 - Regina Arancione.
Joined: 03 Jun 2018
Posts: 1577
Location: Lancaster, U.K.
Sun Sep 01, 2019 7:17 am linkquote
Stromrider wrote:
Is your engine at full working temperature ie: you've ridden it at least 5 miles or more?

If it is at normal working temperature it shouldn't stall but occasionally the engine management system (automatic idle control) can be slow to do it's job, allowing the engine revs to drop a bit more than usual before suddenly normalising. That is kinda normal as long as it's not stalling. Just about all the GTS bikes from 2014 onwards seem to do this. My GTS300 engine idle revs drop dramatically sometimes when I'm in traffic usually when the engine is very hot, and the engine goes to idle after the clutch disengages, but this normally only happens when the engine cooling fan is on in traffic. This loads the engine more than usual, but mine has never stalled.
Thanks Ian, your explanation makes a lot of sense. The symptom only happens when the engine is hot. When I shut off the throttle and the clutch disengages, I feel the revs drop dramatically and a slight pause before the automatic idle control kicks in. Only on the odd occasion does this lead to a stall.

I have only noticed this symptom fairly recently and I wondered if it had something to do with the stretching of the throttle cable. Although the scoot is 5 years old, I have been slow to put miles on (only 3000 Klm's since new). If I were to tighten the cable by a couple of mm, then when I shut off the throttle, there would be less 'slack' in the cable to induce the low revs/automatic idle scenario?
Sun Sep 01, 2019 7:38 am

Veni, Vidi, Posti
In garage: Yamaha Tricity 155 Urban 2019 - MV Agusta 125 RS 1956
Joined: 21 Jul 2007
Posts: 8291
Location: Latina (Italy)
 
Veni, Vidi, Posti
In garage: Yamaha Tricity 155 Urban 2019 - MV Agusta 125 RS 1956
Joined: 21 Jul 2007
Posts: 8291
Location: Latina (Italy)
Sun Sep 01, 2019 7:38 am linkquote
From my experience I can say that the minimum must be kept by the throttle body settings of the injection lock (once with the carburetor there was a screw) even if the throttle cable was slow. Sorry if I disagree ...
True that by pulling the cable you can raise the minimum but (assuming it is the injection model) it is sufficient to go to the dealer who, using a computer, will reprogram the ECU with the correct minimum.
Sun Sep 01, 2019 2:59 pm

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 41062
Location: Pleasant Hill, CA
 
Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 41062
Location: Pleasant Hill, CA
Sun Sep 01, 2019 2:59 pm linkquote
Attila wrote:
From my experience I can say that the minimum must be kept by the throttle body settings of the injection lock (once with the carburetor there was a screw) even if the throttle cable was slow. Sorry if I disagree ...
True that by pulling the cable you can raise the minimum but (assuming it is the injection model) it is sufficient to go to the dealer who, using a computer, will reprogram the ECU with the correct minimum.
Hopefully he'll just upload the most recent mapping into the ECU - there's nearly always an upgrade available.

BUT I do hope that dealer WILL NOT reset the throttle position sensor (TPS). Please read this quote from Cheeky Thomas (a very experienced UK scooter mechanic):
(It's worth reading the whole thing - https://cheekythoma3.wixsite.com/itsme/idle )
Cheeky Thomas wrote:
What Not To Do.
These 2 things are common issues that untrained or simply people that dont know the system can easily do that cause havoc to the systems operation.



DO NOT EVER ADJUST THIS SCREW! This is not a idle screw, its the factory adjuster to set the throttle butterfly at 5.7 degrees open this is a set figure to let the ecu know that if it sees 5.7 degrees on the TPS then the throttle is shut and it operates the stepper motor to control idle, if you therefore adjust this, itll not see the 5.7 reading and therefore not know its at idle so not engage the idle control system, so youll get hunting, stalling, hard starting etc.

The next one is more for dealers, on the diagnostic tool there is an option to reset the TPS, why i dont know as it must NEVER be done after the throttle body has left the factory as it gets done when the butterfly valve is positioned correctly, the workshop manual tells you never to do it, the factory training course tells you never to do it, yet the amount of times ive known people to do it as they dont understand and see the word RESET and cant resist pressing it is beyond me... once pressed the bike now thinks 5.7 degrees is 0 degress and youll get haning idle speeds, stalling when slowing down etc... and the only way to cure it is a new ECU @ £350
Sun Sep 01, 2019 8:12 pm

Hooked
50cc Beo, BigBeo 2003
Joined: 30 May 2015
Posts: 438
Location: Chelyabinsk, Russia
 
Hooked
50cc Beo, BigBeo 2003
Joined: 30 May 2015
Posts: 438
Location: Chelyabinsk, Russia
Sun Sep 01, 2019 8:12 pm linkquote
This might be a symptom of dirty (oily) throttle position sensor, which, in turn, might be a symptom of lots of oil in intake/airbox or too much smoke from crankcase.
Mon Sep 02, 2019 12:27 am

Ossessionato
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
Joined: 11 Jun 2011
Posts: 3766
Location: East Anglia, UK
 
Ossessionato
2016 Vespa GTS300ie abs/asr/ess Settantesimo '70'
Joined: 11 Jun 2011
Posts: 3766
Location: East Anglia, UK
Mon Sep 02, 2019 12:27 am linkquote
Touring300 wrote:
Stromrider wrote:
Is your engine at full working temperature ie: you've ridden it at least 5 miles or more?

If it is at normal working temperature it shouldn't stall but occasionally the engine management system (automatic idle control) can be slow to do it's job, allowing the engine revs to drop a bit more than usual before suddenly normalising. That is kinda normal as long as it's not stalling. Just about all the GTS bikes from 2014 onwards seem to do this. My GTS300 engine idle revs drop dramatically sometimes when I'm in traffic usually when the engine is very hot, and the engine goes to idle after the clutch disengages, but this normally only happens when the engine cooling fan is on in traffic. This loads the engine more than usual, but mine has never stalled.
Thanks Ian, your explanation makes a lot of sense. The symptom only happens when the engine is hot. When I shut off the throttle and the clutch disengages, I feel the revs drop dramatically and a slight pause before the automatic idle control kicks in. Only on the odd occasion does this lead to a stall.

I have only noticed this symptom fairly recently and I wondered if it had something to do with the stretching of the throttle cable. Although the scoot is 5 years old, I have been slow to put miles on (only 3000 Klm's since new). If I were to tighten the cable by a couple of mm, then when I shut off the throttle, there would be less 'slack' in the cable to induce the low revs/automatic idle scenario?
Andrew, yeah as jim is saying, don't adjust the TPS or alter the throttle cable settings. Those actually will make matters worse. It's highly likely an ecu update will cure your occasional stall. Again, as jim says there have been a few since your bike was built and if you haven't had those, then there's the issue I'd say. Good luck and let us know how it goes if you get it done.
Wed Sep 04, 2019 7:36 am

Enthusiast
300 GTS / Husqvarna FE250
Joined: 14 May 2017
Posts: 88
Location: Southend, United Kingdom
 
Enthusiast
300 GTS / Husqvarna FE250
Joined: 14 May 2017
Posts: 88
Location: Southend, United Kingdom
Wed Sep 04, 2019 7:36 am linkquote
Touring300 wrote:
Stromrider wrote:
Is your engine at full working temperature ie: you've ridden it at least 5 miles or more?

If it is at normal working temperature it shouldn't stall but occasionally the engine management system (automatic idle control) can be slow to do it's job, allowing the engine revs to drop a bit more than usual before suddenly normalising. That is kinda normal as long as it's not stalling. Just about all the GTS bikes from 2014 onwards seem to do this. My GTS300 engine idle revs drop dramatically sometimes when I'm in traffic usually when the engine is very hot, and the engine goes to idle after the clutch disengages, but this normally only happens when the engine cooling fan is on in traffic. This loads the engine more than usual, but mine has never stalled.
Thanks Ian, your explanation makes a lot of sense. The symptom only happens when the engine is hot. When I shut off the throttle and the clutch disengages, I feel the revs drop dramatically and a slight pause before the automatic idle control kicks in. Only on the odd occasion does this lead to a stall.

I have only noticed this symptom fairly recently and I wondered if it had something to do with the stretching of the throttle cable. Although the scoot is 5 years old, I have been slow to put miles on (only 3000 Klm's since new). If I were to tighten the cable by a couple of mm, then when I shut off the throttle, there would be less 'slack' in the cable to induce the low revs/automatic idle scenario?
Possible stale fuel? 5k in 5 years isn't much really.
⬆️    About 3 years elapsed between posts    ⬇️
Tue Jun 21, 2022 8:31 am

Molto Verboso
GTS 300ie Touring 2013 - Signora D'argento & GTS 300ie HPE 2022 - Regina Arancione.
Joined: 03 Jun 2018
Posts: 1577
Location: Lancaster, U.K.
 
Molto Verboso
GTS 300ie Touring 2013 - Signora D'argento & GTS 300ie HPE 2022 - Regina Arancione.
Joined: 03 Jun 2018
Posts: 1577
Location: Lancaster, U.K.
Tue Jun 21, 2022 8:31 am linkquote
So finally, 3 years later, I have resolved my 'stalling when clutch disengages' issue. What had started out in 2019 as an 'occasional stall' had slowly over time, manifested itself into 'stalling on most occasions' when free-wheeling to a stop and the clutch disengaging from the engine.

My scooter has always run perfectly except for this very specific issue of the engine stalling out when rolling to a stop, just as the clutch disengages from the engine. Since then I have followed similar stalling issue threads on MV and observed the many members suggestions as possible remedies. As this summer arrived, I decided to change my decision from accepting and living with the fault (especially as some owners' reactions to my symptoms were, "well they all do that") to pro-actively attempting to getting to the bottom of it. Here is a list of actions I took in my search to find the possible cause:

The first step I took was to book my scooter in with my nearest Vespa/Piaggio dealer in the hope that the P.A.D.S diagnostics would offer-up an ECU update and all would be well. Sadly there was no diagnostic update to be had for my GTS and after the mechanic took it out for a test ride, managing in the process to induce the stall, he returned telling me he could not suggest a remedy and advised I could spend many hours and many ££££, and still not find the root cause.

Returning home somewhat dejected, I embarked on a fault finding mission. Here is the list of things I checked:

Health of the battery, checked the 'kill switch', added fuel/injector cleaner into the petrol tank, cleaned the air filter, replaced the spark plug and checked the spark plug cable, adjusted the 'play' in the throttle cable, cleaned the throttle body using specific throttle body cleaner, dropped the engine and checked the valve clearances, removed the fuel injector and sent it away to be professionally cleaned (I was not confident that I would be able to clean it thoroughly enough and the cleaning service only cost £25.00 which included return postage and a printed graph showing pre/post test results).

I was considering replacing the fuel pump, but I did not need to as the culprit was found. A discounted and brand new ECU/Throttle Body for my year of GTS was sourced which, when installed, instantly cured the stall. Since the install I have been out on a couple of long rides during which I deliberately coasted to a stop many times with the throttle rolled off, and the engine has not stalled once. I am a very happy chappie
Tue Jun 21, 2022 11:51 am

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 41062
Location: Pleasant Hill, CA
 
Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 41062
Location: Pleasant Hill, CA
Tue Jun 21, 2022 11:51 am linkquote
That all makes me wonder if some misguided mechanic re-set the Throttle Position Sensor at some point - which is specifically pronounced as a NO-NO in the workshop manual (unless a brand-new throttle body is installed).
Tue Jun 21, 2022 12:50 pm

Addicted
Tethys - 2012 GTS 300
Joined: 22 Jul 2008
Posts: 739
Location: Bowie, MD
 
Addicted
Tethys - 2012 GTS 300
Joined: 22 Jul 2008
Posts: 739
Location: Bowie, MD
Tue Jun 21, 2022 12:50 pm linkquote
Thanks for posting your process and the resolution! I got a new wrinkle in my brain.
Tue Jun 21, 2022 3:12 pm

Molto Verboso
2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1620
Location: Batmania aka Melbourne, Australia
 
Molto Verboso
2019 Supertech (EURO3/APAC)
Joined: 17 Nov 2020
Posts: 1620
Location: Batmania aka Melbourne, Australia
Tue Jun 21, 2022 3:12 pm linkquote
jimc wrote:
That all makes me wonder if some misguided mechanic re-set the Throttle Position Sensor at some point - which is specifically pronounced as a NO-NO in the workshop manual (unless a brand-new throttle body is installed).
or worn out like mine was in my supertech
Tue Jun 21, 2022 3:35 pm

Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 41062
Location: Pleasant Hill, CA
 
Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 41062
Location: Pleasant Hill, CA
Tue Jun 21, 2022 3:35 pm linkquote
steelbytes wrote:
or worn out like mine was in my supertech
True - of course Piaggio would say that it should be replaced, but resetting the TPS at least enables the worn-out one to keep going for a while.
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