Modern Vespa

I've just bought a used GTS300. It's a 2011 modell, but is hasn't been running for the last year or so, because it doesn't start. Seller think it's an issue with ECU. I hope there can be another issue, but need some tip if you can help me
I hasn't got it home to myself yet, but will have is soon.

This is what I know been changed:
- Air filter element
- Fuel pump

Following parts has been tested from other Vespa 300 that works:
- Injector
- Spark plug
- Lambda sensor

Engine turn when push start, it has spark, fuel and air. If Injector is loose
(taken a little out it does start but run very strange) has been told me

Thanks in advance

People will say all sorts of things when trying to offload a bike that doesn't start and run.
The truth will reveal itself when it becomes your bike......

did you check these or is this what you have been told? you started the engine with the fuel injector partially pulled out? really?

Hi,
pull the fuel line off and turn the bike on the fuel pump should prime the line and flow out.

pull the injector out and push start to see the fuel spray, if its a good spray then put it back in and secure.

check to see the exhaust it not blocked, push some wire down it.

if you have spark and fuel then remove the air cleaner and try to start it.

partially out is no issue at all.

although I wouldn't try it, the more interesting claim is that allowed it to start

Fuel, spark and air it will fire, dont get me wrong it will run rough and wont hurt anything over the short period you gauging if you have flow at the injector.

sure, but why did it make a difference. the extra air getting in there would suggest it ain't getting in through the airbox or tb

It could be the electrical connection to the injector - on the wire (not the injector) side.

that could explain it.

Check the wire loom I have seen a lot over the past few years melting due to a broken wire or bad earth.

That's right

Both has been told, so will see when scooter is at place

I will start from scratch with basic check, and won't think of what I've been told.

Will be checked when I go thru electric connections from Service manual

Will be checked good when I go thru point for point

If ECU is the problem will it be spark or not?
I understand that ECU on this scooters can be a problem, and I suppose there is a print card inside it?
Have anybody tried to "baked" it?

Then I got the Scooter home and have some more information / details

There was almost no fuel in tank, but I was able to start it. It didn't run nice.
It run very hard and I had to turn gas handle to almost middle to have it run, when I toke gas handle back to idle it stopped. I filled 5 liters of new gasoline, and started it again, still same problem. Stopped it and looked under seat, the air filter hose was not connected into throttle body. I mounted that and tried to start, not possible. After a little while the battery was not top anymore so I stopped it. Tomorrow I will go the the dealer and get the missing exhaust gasket I will also borrow a charger so I can top up the battery.

So It can seem it only start with air filter hose disconnected

Anybody with some tip for what to look for?

this really makes me think the airbox / airfilter is clogged. eg Maybe there is a wasp nest in the box (seriously can happen)

Check the exhaust is not blocked with mud wasp or a mouse is blocking the air box

Air filter is not blocked and the exhaust is missing a gasket so it's not blocked either

Air filter is not blocked or clogged.

The scooter did came with another Throttle body. It's used also. I swapped it today and tried to programmed my keys but I could not get it programmed.
Can the throttle body then be damage or?

The brown key is the brains of the operation, the blue key as a copy. I'm thinking throttle body as it has the ECU in it.

a used ecu needs to be 'virginised' before you can program it. (discussed in other threads). or if it came with it's own keys (blue and/or brown) then just use those

well if it ain't that then it takes me back to thinking what jimc said that the connections somewhere have been damaged and attaching the airbox hose moved these wires enough to affect things.

The marked part in attachment is missing from the air filter box

The marked part is SKU 844921. But it seems that this item does not fit a '2011 Vespa GTS 300 ZAPM45200:
https://www.sip-scootershop.com/en/product/intake-tube-piaggio-air-filter-box_PI844921


Assume that this exploded view is used for more than your vehicle type (this may the also the reason that it doesn't have a (clickable) number in your screenshot).

Please let us know your VIN-Prefix (first 9 digits) to check if ZAPM45200 is correct.

Here it is ZAPM452000

Then I think I found the fault
I have checked the timing of cam axle and it look to be 1 tooth wrong

First picture show that the 4V marking is not on the point it shall be, second picture show that the marking on opposite side on engine is on marking

Well found. Check the chain tensioner and the chain guides.

Can the chain go over a teeth or two by it selves?

What can have happen here?

Not if the chain tensioner and chain guides are in good condition.

I open the tensioner to day, then I was able to take the chain of the sprocket, moved the cam 2 teeth's. I mounted the tensioner again, turned engine by hand, everything seem ok. turned the engine on starter without spark plug, also everything ok. Then with spark plug. It started
I let it go a little on idle, before I run a short trip for just 200 meters. Everything work ok. I can't take a longer test run yet since I miss the exhaust bush between lambda tube and muffler.

somebody know where this part should have been mounted

Spark plug cap bracket?

Yes, there it is...

Thanks