Modern Vespa

Hi Vespa men,
I have a problem with my starter, in fact, starter relay. I have the same problem before and right now always the same with a new relay.
Sometimes, when relay is hot and it's the doesn't start at the first turns, the relay is locked.
It's make a "click" and the starter doesn't turn on.

I open it, because it really easy. It's look like when the intensity is too high, it's make a spark between contact plates on the relay, that push down mobile plate.

Now I make a hole into the relay cover to push directly on the mobile plate. It's okay like this to start the motor.
Obviously, there no problem with the starter (except maybe it's need too much intensity), no problem with the battery, no problem with the starter button.

Have you an idea of why the mobile plate doesn't stay stick on the contact play???

I did some tests today. The problem is coming from the command and not the power supply.
The contact on the handlebar is closing the circuit with the mass. It works sometimes and sometimes not.

Have some returns on a problem with handle bar starter switch?

That's why they sell a lot of handlebar switches and they're very inexpensive. They wear out.

I will see that. I have ordered a new switch

Hi,
I have changed the starter switch today. Same result. I have tried to make contact directly between the 2 cables inside the plug of the starter switch. Same as the switch. It's not working all time.

Wires haven't the same colors between the relay one and the switch. And also, when the relay is block, every 5 secondes, the relay try to make the contact with a "click".

There is a control in an other place into the scooter?? EFI control unit??

The wires won't be the same colour. The starter switch sends 12V to the ECU (MA-Rs = Brown/Red) which then grounds the starter relay (Ar-Bl = Orange/Blue) whose coil gets 12V from the brake light switches.

Wiring diagram here:
https://manuals.wotmeworry.org.uk/Vespa/GTS300-2015-ABS/

The ECU won't ground the relay if it thinks there's any problem which should prevent starting. The most obvious being the kill switch (and side stand switch if fitted) - both of which are prone to becoming intermittent.

Google translate:

Les fils ne seront pas de la même couleur. Le contacteur de démarrage envoie 12 V à l'ECU (MA-Rs = Marron/Rouge), qui met ensuite à la masse le relais de démarrage (Ar-Bl = Orange/Bleu), dont la bobine est alimentée en 12 V par les contacteurs de feux stop.

Schéma de câblage ici :
https://manuals.wotmeworry.org.uk/Vespa/GTS300-2015-ABS/

L'ECU ne met pas le relais à la masse s'il détecte un problème empêchant le démarrage. Le plus évident est le coupe-circuit (et le contacteur de béquille latérale, le cas échéant), qui ont tous deux tendance à fonctionner par intermittence.

Thank you for your return. I don't have the side stand switch.

There no strict interdiction. Just a "click". The relay makes the contact just few milliseconds.

I will have a look on wire diagram and clean ECU plug.

👍

Aha - check the voltage at the battery when this happens - it may drop so low that the ECU gives up holding the relay coil to ground. Try a new battery - or at least a jump start from a car battery.

It could all be down to an intermittent connection within the battery - I've met that before!

I will test the battery also. I will try after charging the battery, or with an external power supply 12 V.

It's often happen when is difficult for the starter (2 nd or 3 rd start)or when scooter is hot. It could be an explanation.

Thank for your help !! 👍

Hi,
I have made some tests today. First of all, I have tried to start the motor in the normal way and it's started like 5 or 6 times. After, it was off. Just click, click (I have made a video of that).
I have tested battery today. It's good 12,5 V, and not a lot of miss of tension when starter is running.
I also have tested with auxilary 12 V generator.
It's the same problem. It's look like the ECU is not able to keep contact on the relay.
I also have cleaned ECU contacts.