Modern Vespa

Hi guys i have an Gilera Fuoco 500 2010 that will act funny when idling cold. Will die when coming to stop until the engine warms up. I am mechanic technician by job so no strange to car sensors etc.
Looking in the service manual i see this scooter doesn't have a MAP sensor? couldn't find anywhere and diagnostic tool will read constantly 1024 mbar.
Throttle body was very dirty so i dissasembled the unit+ECU not to get cleaning solutionn inside, made it like brand new again nothing was damaged i seen many break the PCB board because they don't know the scred holds it to the cover.
Every sensor is working, and diag tool is reading all the values. IAC stepper is working can even hear it...
Problem is if i let the throttle stop scrw at factory will idle rough, it's set to 3.4 degrees and if i back it out to 1.7-2degree will idle better and coming to stop better when warming up or even under load.
VAlve clearances were out of specs, around 0.28mm in/ex, set them to factory 0.15mm.
Injector was cleaned and is running perfect.
Measured AFR and is around 12, which is too rich for idle, and spark plugs get soothed black quickly

Problems that i did not repaired so far:
-coolant temp sensor is reading a bit funny, an checking the 5v circuit both at the ecu connector or the one going to the dash, will act different (it has 2 thermistors inside, but should read the same) - SUSPECT nr. 1
-fuel pressure is 3.3 bar not 2.9-3.0 bar as manual specs. - SUSPECT nr. 2

Any other problems that might be? In my opinion i've ruled out everything.
Would highly appreciate any ideas..i'm running out of them..

what fuel spec are you using?

Air leak on the intake? One of the rubber intake hoses cracked on my Vespa recently

It;s not related to type of fuel, regular 95 or 100+ the same.
It doesn't have an air leak.

Throttle body was super dirty when i took it off, like a diesel engine intake..lots of dirt

I think it got sorted out yesterday. While adjusting the throttle butterfly stop screw, messed with it a bit on other angles than diagnostic tool reset of 3.4 degree or 2 degree that works better...while turning it while around 3 degrees it jumped to 8-9 degrees, and then jumped back to 3.. turned in and out for another 10 minutes continuously, again the same situation jumped twice to 7-8-9 degrees...
For me, this is a TPS issue, so the TPS being directly in contact with the ECU PCB..will need a new ECU.

At least this is the only fault that makes sense. If it had an OBD2 diag connector i could have checked the TPS with the oscilloscope...but for this 3 pin connector i can.t just have to rely on the TEXA diagnostic tool.

A shame you messed with the throttle stop screw - that is set at the factory along with the TPS. The manual specifically warns against adjusting this!

brother, i'm a car & motorcycle technician, engineer and japanese motorcycles specialist. We don't deal with these MIU ecm usually, previously also diagnosed a CAN BUS problem on this Fuoco 500 also, that 2 other repair shops changed parking module for nothing.
The stop screw is available on every single bike with EFI that sets it's own idle rpm.
Manual warns not to mess with it because most people will think it's an idle set screw.
This setup is used on cars since early 2000.
I came here on this forum beucase it's always something new to learn, and also it may be an instance that somebody had the exact same issue, and where i came from we TECHNICIANS help each other because nobody knows it all...

I am amazed you noticed that i modified the stop screw and not saying anything that i've opened the throttle body/ECM

Hi carlssonlove
Thank you for sharing your expertise and knowledge with the forum.

Somewhere in the near future your answer will be the key that solves a repair for a professional or armature mechanic.

thanks brother, i wisheed some one who works on these scooters more often can get involved so that i can get deeper into this problem

for example i've adjusted back out throttle stop screw a couple days before from 3.4 deg to 2 deg, and it didn't jump chaotic, but once i go up over 3 deg it has it's moments and it takes around 10-15 minutes do make it act when adjusting throttle stop screw... very awfull situation and bad module design...

nothing about changing the spark plugs, hmm

I'm not certain which ecu + tb you have but i think yours does have one.

below is a ecu+tb that piaggio uses from around 2013. I think some of the previous version of these ecus also has one

This is a Gilera Fuoco 2010.

yes, but what is the ecu/tb? I know it's not a miug3 but is it a miu1? or what? I only showed the 3 photo because it was a handy photo to show the MAP. Both the 1* and 3 have a MAP

* couldn't find a photo but it is in the miu1 code

i'll attach pictures below, for developing the subject since we are on it. The ones you posted have an internal map sensor indeed, there is a tube that goes to the sensor, but if it's on the PCB not worth repairing also
This is before and after i opened it to clean it, because if i didn't opened it from the stepper motor and TPS cleaning solutions could get inside and damage the PCB

and this is the one with the MAP sensor onboard.
i was thinking that this variant of FUOCO 500 may have an external map sensor the there's no vacuum hose anywhere on the intake manifold, air box or other place.

also does anyone know what aftermarket fuel filter will fit it? i've seen it's a particular size an here in cost almost 80euros

this is the short neck vershion that bolts into the intake. sorry for 3 messages but it seems i can't add more than 1 picture/message

Hi,
did the OP succeeded in solving his issue?
Thx
Jo