Modern Vespa

Excuse my english.... I'm swedish but lives in France...
I've searched the forum but not found my problem.
My Vespa ET4 GTS is a 125 cc year 2017. I've had the same problem before but then the dealer (I think) changed the throttle body (they call it papilion/butterly here) and it got somewhat better. Now my scooter was not used for 11 month and when driving the problem returned. Starting is fine but after driving a few minutes (I guess when the ECU stops the automatic choke) the motor stops at read lights or cruising when not giving gas. Annoying and dangerous. But, when the motor gets hot (after 7-10 minutes or so) there is is no problem. Idle is perfect. I tried to disconnect the sensor sitting on top of the throttle assembly (measuring airflow?) and the motor works almost better or the same but much lower rpm (i guess) when idle but it does not stop all the time. Just sometimes. Then when hot it works fine as usual. I've understood I need to change the whole assembly but its 200 euros. Is changing the assembly the thing to do or could I check something else before? Is it worth the effort of cleaning the carburator/throttle assembly?

Hello do you solve the problem?
I am having the same problem
Thanks

I will try yo explain with my bad english Noo.... But I found a work around, I think. I undid the screw that affects the manual idle, I put another screw thats more easy to adjust and I bought a thacometer to measure the RPM. Now I have a higher RPM when idle (I force it manually) around 1000 RPM but the yellow lamp warning motor is shining on the control panel. Be careful with the idle screw. If the idle is to high its easy the motor revs up to 1500 rpm and then the belt begins to turn. I bought a Pollini(?) variator and clutch kit and the spring should be a bit harder and allow for 20% more rpm before the variator and clutch kicks in. In tehory..... I have not yet installed it.

Hello thanks for your answer, you should not Mess with the idle screw,
The problem is the throttle body, i read on internet that affects almost every 125 IGET engines.
When cold the engine have more air then gasoline, that causes the stall problem!
Piaggio dealers have an update for this!
Or you can talk with a tunner and remap your ECU!
Have you try To read ecu error?
Mine error is related To O2 sensor
Many thanks

Hello again the valve that you show in first post is the idle valve, only works at idle, when throtlle is aplied stop working, it is called idle adjustment valve.

When the bike is at idle the buterfly on throtlle body Must be Close, then the idle valve provide air for the engine.

Thanks for your answer! I messed with the idle screw bcs I needed my Vespa to work..... Oups! Not good...

What are you using as a diagnostic tool? I've been working a lot with my car ( a LR Defender) but the Vespa is new for me. I read that only Piaggios diagnostic tool could be used. And the throttle with the idle sensor has already been changed one time under the warranty. Strange that the error occurs yet one more time. I need to go to my local garage and that hurts bcs they already "helped" me. And a visit is always expensive....
So, I have no idea of what I've done but it seems to work for the moment.

Is there any good diagnostic tools and, as I'm new to this motor have you any links to enterprises that can remap my ECU? That I've done with my car.

I can help you with diagnostic tool!
Remap tool! NO
Remap must be done by an experient tuner!!
Don t Mess with ecu if you don t have experience
Please visit vespa piaggio
You need a throttle body flap buterfly reset

Hello
Have you Tried to clean the injector?
If the scooter was 12 months without running
Maybe injector is cloged with bad fuel
Check YouTube there is a vídeo
How to do it
Please keep me update
Many thanks
Cheers from Portugal

Thank you! No, I will not mess with the ECU thats for the garage
But I was thinking of cleaning the injector when I have time and have already looked at youtube videos. I can do that but I need a day or so.

Can you tell me any good ODB2 reader that works ok for my Vespa?

/A

Hello good morming
Obd you can bought an elm 327 bluethoot or wifi ( only Wi-Fi works with iphone).
You can download Any app like torque, 4stroke, then you need an obd adapter like fiat style, 3 pins To femalle 16 pins that can be bought on ebay, AliExpress!
And works on vespas gts from 2016 up To 2022

Hello
Please I am going to change this part
It is suposed to hold vacuum and it didn t
Please check on ebay bosch and the parts number!
In piaggio they only Sell with the throttle body 250eu
I hope it helps
Cheers from portugal

Thank you I guess its that valve I need to change and I am not happy to change the whole kit for 200+ euros. easyparts.com sell it for 200 euros. So, I will search on ebay. Super! I just do not have time, but now I will find some time.

Tomorrow I will stop by at my local Vespa dealer. They have been closed during winter but are now open for business.

As for the OBD reader. I think its a jungle..... I have one for my LR Defender but its made for my car. With that I can do a LOT of things I searched ELM 327 and I found several readers with the same name. I guess I have to try one of them

Please tell me if it helped you changing the Bosch valve.

Cheers from France!

Hello friend
I bought from ebay
Letónia contry
Shipping is about 2 weeks
Cost 25 euros
Buy one for you
Piaggio only Sell with throttle body

I found the same, from Letonia. I will buy it but I wait until tomorrow what the Vespa vendor tells me. But I think it will do the thing Thank you!

This is the cable
With My elm

Don t buy the cheap ones

Just to help you
My error is related with o2 sensor
And I change it // no fix
I change also coolant temp sensor // no fix

The o2 error is related to air fuel ratio by the ecu
Means that the engine have more air then fuel

Today I test that valve, the valve do the idle adjustment!!

When engine is cold
Valve open to provide engine more air

When engine is warm
Valve close
A warmer engine needs less air and fuel!!

I test valve for vacuum hold when close
And the valve continues to let air pass to the injetion chamber!

As far as I know piaggio only sells the valve with throttle body assembly
Costs 250euros

I check online with the valve parts number and I found it

If it isn't the valve
I can keep it as a spare part

Sorry for My bad english
I am portuguese not english😁

Some pictures of my baby girl
Love it,
I hope it helps you
👍

what is the part number?

not up to 2022. The HPE GTS use this cable. And I think also latest primavera etc.

https://www.aliexpress.com/item/1005003540612076.html?spm=a2g0s.8937460.0.0.b8232e0eA0KsjQ

more info at GUIDE: How to read Engine Fault Codes (OBD/OBD2)

Hey steelbytes
Mine is 125 engine
Old cable
But work!
Please take a look at this post, I figure it out where mine intake leak is!!
I can help you because HPE 300 engine is diferent
👌✌️

Part number for the solenoid valve
Bosch 0280142539
This solenoid valve makes de idle adjustment in 125 IGET engines!!
I don t know why the heck piaggio use this valve for idle!!

This valve is used in car industry for EVAP canister
Valve ( ventilation of fuel tank).

I am very unhappy with piaggio, the price is huge, but the quality is becoming very lower!!

Exactly! It's to expensive for the quality. It's the third time I'm having the same problem. Mine is an 2017 soon 10.000 km

Mine as only 1600km
😆
Let's pray, that we can solve the problem
I advise you also to check your battery, if you never change the battery, because a low battery can cause stalling issues too.

Thanks! I recently changed the battery. I bought the same as before and I charge it with a C-tek charger. A week battery can cause much problems......

Now I'm will disconnect the valve when going to Sainte Maxime. 8 km. Lets see

Friend disconnect the valve
Put one screw in the end pipe
And let it With the plug connect
I did that
Bike stars at first try
Just don t idle very well for the first 30 sec
I clear check engine light, and didn t came on!!
👍

"Just don t idle very well for the first 30 sec"

That was the problem to begin with... I tried to compensate with adjusting the idle screw.

I have had no time to investigate further and with the valve disconnected it works better but not 100%. I find the motor have more torque though! Not bad.

I will take it to the garage one day soon and ask them to measure.

Do you know if there are any companies who reprogram the ECU? I have bought a Pollini clutch and variator kit and with some more torque it would be perfect.

Friend
I disconnect the valve Until the new one arrives
Bought a new solenoid Bosh valve like me and you Will solve the problem

Hello! Did it work? I havent have time to use my Vespa so I've done nothing. But the weather is better..... Did the new valve work?


/Anders

Hello
Yes new valve fit, and throttle position sensor reset at piaggio, bike is now good.
You have to use more your vespa, and don t let it sit down Too much time, because the battery gets flat with no charge and the ECU looses sincronization with the thottle body position sensor!
My vespa is now ok, right now even without use it, I start it and
Let it work just to charge batery
Best regards my friend

Hello and thank you for the info! I go to sweden time on time and leave my Vespa. Last time I stayed 11 months thanks to Corona and other things..... when coming back my battery was stone dead and I had to buy a new one. Where I keep my Vespa for long time storage I can not charge my battery. Sad.

No I know the importance!
In a few weeks I go to sweden for 3 months.
Lets see what I can do. I think I try to repaire when I come back and then in the future make a solution for charging when i'm not here.
Maybe a solar panel?
Regards
Anders

Hello My friend
You can buy a battery device for maintenance and leave it plug to a solar panel
Yessss good ideia!
Don t forget you need a TPS reset at paiggio
Have a Nice weekend
Best regards from Portugal

Hello Mr Grey, greetings from Thailand! I have the same problem with cold start, no power and stalling, it's good when the motor is warm. Did you end up replacing that Bosch Throttle Body Solenoid Valve? Did it work? I am having the same problem with my 2017 GTS 150 16000kms. No one in Thailand can fix this and the dealer says cannot fix sell the bike. I love my Vespa and I don't want to sell. I cannot understand how it's not possible to fix.