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UTC

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Vespa GTS 125
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Location: Warsaw, Poland
 
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Vespa GTS 125
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UTC quote
Hi everyone, first time poster here ✌️ I am Jakub from Poland.
I searched for an answer to my problem within wiki and forum posts, but no luck
My Vespa cranks, but doesn't start.
Fuel pump works, I hear the sound when I turn ignition, and the fuel is in the hose supplying injection system, so it is pressurized. I cleaned old injector with injection system cleaning fluid and compressed air, and it fired - I went for a 500meter ride and the engine went down and since then cannot start. Thinking the problem might be with faulty injector, I ordered new one (looks like it squirts fuel fine - see video: https://photos.app.goo.gl/fXyazfVvHo8U4Lyy6 ). Today it arrived, replaced it and the problem remains unsolved. Same story. Cranks, but doesn't start (see video: https://photos.app.goo.gl/TT8ffuxiWTTvhmrH8 ). Sparkplug is replaced, the spark is good (see video: https://photos.app.goo.gl/JZ8w6KhCnJLD5sDj7 ). Immobiliser seems to be coded with the key.
Killswitch checked and working ok.
Air filter cleaned.
ABS light is blinking all the time when key is in ignition position - I cannot remember how was it before problems started, nor can't find an answer here if it is normal (see video: https://photos.app.goo.gl/6RhZgHagSYZAr6ATA ).
When I hold brake lever, push the start button, release the start button, release brake lever it stops cranking, but when I immediately hold brake lever again - it starts cranking even if the start button wasn't pressed again.... (see video: https://photos.app.goo.gl/n5YFU8h3weNGwD6P9 ) Not sure if it is something specific to my problem or is it normal behavior
What can be the reason? I am outta ideas 🤷‍♂️ I appreciate any help from Vespa Gurus here! Thanks in advance.
⚠️ Last edited by jakubradecki on UTC; edited 4 times
UTC

Hooked
300gts super sport
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Hooked
300gts super sport
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UTC quote
If you have fuel and spark something is happening in the cylinder. Have you checked your valve clearances?
@steelbytes avatar
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Veni, Vidi, Posti
2019 GTS300 HPE SuperTech 66,000km
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@steelbytes avatar
2019 GTS300 HPE SuperTech 66,000km
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Location: Batmania aka Melbourne, Australia
UTC quote
jakubradecki wrote:
When I hold brake lever, push the start button, release the start button, release brake lever it stops cranking, but when I immediately hold brake lever again - it starts cranking even if the start button wasn't pressed again.... Not sure if it is something specific to my problem or is it normal behavior
it should never crank when the button is not pressed.
@jimc avatar
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The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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@jimc avatar
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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I've had a shorted out starter switch before now - but that was the old round button type on an X9, the spring had corroded, bent sideways and jammed the switch on.

In this case though it might just be a slow release for some reason? Whatever, I don't think it's related to no starting.

Have you tested the new injector, and ensured it's squirting? The connections to it are very fragile.
OP
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Vespa GTS 125
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Vespa GTS 125
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Hi - please take a look: https://photos.app.goo.gl/fXyazfVvHo8U4Lyy6
I think it squirts just fine, but I am not sure if this is ok...
jimc wrote:
I've had a shorted out starter switch before now - but that was the old round button type on an X9, the spring had corroded, bent sideways and jammed the switch on.

In this case though it might just be a slow release for some reason? Whatever, I don't think it's related to no starting.

Have you tested the new injector, and ensured it's squirting? The connections to it are very fragile.
OP
UTC

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Vespa GTS 125
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It is just one, short crank, but it is definitely done without start button being pressed - please take a look at the video: https://photos.app.goo.gl/n5YFU8h3weNGwD6P9
SteelBytes wrote:
it should never crank when the button is not pressed.
OP
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Vespa GTS 125
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UTC quote
One more maybe important info: it does not crank when the throttle is open, or immediately stops cranking when I pull the throttle during start: (see video: https://photos.app.goo.gl/imvszHZ5ECUVHunV6 )

Plus, I managed to connect IAW Diag today - it returned following errors:

P0201 Linke Einspritzdüse: no signal
P0651: no signal
P0530: to low
P0611 Gespeicherte Daten: invalid signal

After resetting errors, following remained:

P0651 : no signal
P0611 Gespeicherte Daten : invalid signal

Here's full report:


IAW Diag V0.52 2024.05.08 19:23


MIUG3 IAW MIUG3
CM084826
32M3G1HW306
3523BR32
E15A
2014.10.09


Measurements

RPM: 0
RPM #: 0
Intake pressure: 1015
Air temperature: 30 °C
Engine temperature: 16 °C
Throttle: 3.6 °
Programmed advance: 0.00 °
Advance right: 10.00 °
Advance left: 10.00 °
Injection right: 0.00 ms
Injection left: 6.59 ms
Targeted idle RPM: 1100
Voltage: 11.4 V
Frontspeed: 0
Rearspeed: 0
Lambda voltage left: 0 mV
Lambda voltage right: 0 mV
Mixture corr. left: 0.00 %
Mixture corr. right: 0.00 %
Fuel adapt. corr. left: 0.00 %
Fuel adapt. corr. right: 0.00 %
Air pressure: 1015
Throttle equiv. Stepper: 0.00 °
Programmed steps: 68
Carried out steps: 170
Key On counting: 3910
Status mixture left: 128
Status mixture right: 128
Status Lambda left: 00000001
Status Lambda right: 00000000
Status engine: 00001000
Status engine mode: Undetermined
Status handlebar: 00000001
Status gear: 1
Status idle control: 10000000
Status display: 0
Status side stand: 0
Status clutch: 1
Status kill switch: 0
Status starting Ok: 1
Status ignition request: 0
Lambda Loop left: Open loop
Lambda Loop right: Open loop
Lambda mixture left: lean
Lambda mixture right: not active
Lambda state left: not active
Lambda state right: not active
Unknown 3B: 0
Unknown 3D: 0
Unknown 3E: 0
Unknown 3F: 0
Unknown 40: 0
Unknown 41: 0
Unknown 42: 0
Unknown 43: 0
Unknown 44: 0
Unknown 4D: 0
Unknown 4E: 0
Unknown 50: 0
Unknown 51: 0
Unknown 52: 0
Unknown 54: 1785
Unknown 55: 0
Unknown 56: 0
Unknown 59: 0
Unknown 5D: 0
Unknown 5E: 0
Unknown 5F: 0
Unknown 64: 0
Unknown 65: 0
Unknown 66: 1
Unknown 67: -40 °C
Unknown 68: -40 °C
Unknown 69: -40 °C
Unknown 6D: 53
Unknown 6E: 0
Unknown 6F: 0
Unknown 70: 0
Unknown 71: 0
Unknown 73: 0
Unknown 74: 0
Unknown 77: 1
Unknown 7B: 2
Unknown 7C: 0
Unknown 7D: 0

Status
Engine off (08)
Engine mode: 0
Side stand in
Clutch pulled
Throttle closed
Gear neutral
Killswitch active
Start possible
Unknown 1 : 80
Unknown 2 : 80
Unknown 3 : 47


Faults


Stored faults: P0651 : no signal
P0611 Gespeicherte Daten : invalid signal
@jimc avatar
UTC

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The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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jakubradecki wrote:
One more maybe important info: it does not crank when the throttle is open, or immediately stops cranking when I pull the throttle during start:
That's by design. Earlier models do not have this feature though.
OP
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Vespa GTS 125
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One idea came across my mind: maybe the reason is this relay?
Forum member supplied image with no explanatory text
@jimc avatar
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The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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UTC quote
That's the starter relay. If the starter motor works - that relay is good.
@chachi13 avatar
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jakubradecki wrote:
Voltage: 11.4 V
Could this be the problem?
@jimc avatar
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The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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UTC quote
Chachi13 wrote:
Could this be the problem?
It could be by now, if the battery hasn't been fully charged in between multiple tries. However, the first video shows the engine turning over at a good speed, so at *that* time the battery must have been fine.
@steelbytes avatar
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2019 GTS300 HPE SuperTech 66,000km
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UTC quote
Chachi13 wrote:
Could this be the problem?
Well spotted
OP
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Vespa GTS 125
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UTC quote
Chachi13 wrote:
Could this be the problem?
Thanks for the tip, but the battery almost was almost empty because of multiple cranking attempts. Now it is charged, and charger shows 12.6V
OP
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Vespa GTS 125
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UTC quote
jimc wrote:
That's the starter relay. If the starter motor works - that relay is good.
Thanks, I read somewhere at the forum that people had problems with this. Maybe there are other relays somewhere that may cause this kind of problems - I really run out of all ideas.. Spark is good, fuel is being injected, air filter clean, immobiliser OK, killswitch working :/
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vespa gts
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1 The tilt or tip-over sensor is activated if the scooter falls on its side. The sensor is connected to the ECU - in the event of a fall, the ECU cuts power to the engine management system. Before the engine can be restarted the scooter must be stood upright and the ignition turned OFF and then back ON again to allow the start-up self-diagnosis programme to run.

it might be the tip over sensor
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2013 BV350, 2014 GTS , 2016 GTS, 2013 Downtown 300i, 2018 Like 150i
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UTC quote
jakubradecki wrote:
When I hold brake lever, push the start button, release the start button, release brake lever it stops cranking, but when I immediately hold brake lever again - it starts cranking even if the start button wasn't pressed again....
See my tail of woe in another "non start" topic currently running. I haven't seen your wiring diagram, but if they engineered it similar to the 2016 GTS (usa), then it sounds like the ground side of the relay is shorting to ground else the computer is wonky.

Pulling the brake lever supplies 12v to one side of the control pin of the relay. In order to complete the circuit and cause the starter motor to engage, the computer pulls the other side/pin of the relay to ground when you press the start switch. If you are getting engagement with just the pull of the brake lever, it means the other side is already at ground (get a VOM and measure it!). The ways that could happen include a bad start switch, a shorted wiring harness, or a bad computer.
Again, this applies to a 2016 300 GTS, but I'll bet it also applies to the earlier ABS models in Europe.

BTW, if that is indeed the case, the the fix that I did to my bike would also work on yours.

Does bypassing the relay (momentarily short the two thick cables attached to the relay) with the engine key turned on start your bike?
If you wire the two control sides of the relay to a 9v battery (polarity doesnt matter), does it crank over the bike? If the bike is turned on, does this start the bike?
OP
UTC

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Vespa GTS 125
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Location: Warsaw, Poland
 
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Vespa GTS 125
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Location: Warsaw, Poland
UTC quote
PROBLEM SOLVED!

Direct problem was burnt insolation on the ignition cable between coil and sparkplug (see photos). Because of this, there was short-circuit between cable and frame/engine body.
I have to further investigate that, because I am 100% sure it wasn't burnt when the problem occurred for the first time - It was my initial thought to check sparkplug (I replaced it) and resistance of sparkplug connection (was fine), so I also visually inspected cable and there was definitely no burnt/melted insulation. Strange. Did diagnostic with only ignition on and with engine running, and following errors show up still and I cannot reset it:

P0651 : no signal
P0611 Gespeicherte Daten : invalid signal
Forum member supplied image with no explanatory text
Forum member supplied image with no explanatory text
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