Modern Vespa

I'm posted before on my 2018 liberty 150. She runs beautifully but struggles on idle when first started and can stall. If I restart it, say 30-60 min after running, it can struggle and stall much more often. Again, once warmed up, she's golden. And and throttle given it won't stall.

My latest improvements were cleaning out the IAC valve with throttle body cleaner and also replaced the whole darn fuel pump assembly (with fuel filter). That was an expensive part... It "seems" marginally better, usually won't stall at cold start but it takes longer on the starter than I like and a hot restart still can stall. It's more of an annoyance (and embarassing) than anything else.

I could replace the stepper (the IAC), that control air for idle. I'm hesitant as it won't be cheap and scooterwest has to custom order it from overseas...

So, I'm thinking maybe I test bypassing the EVAP system to see if the purge valve or canister is bad. Thoughts?

If I do, I guess I need to see where a hose goes into the throttle body and remove and cap it (so air isn't getting into the throttle body). And then also disconnect another hose from the fuel tank and not cap it (so it can vent and not build up pressure). Correct?

I know there's differences with carb vs fuel inject models, so just confirming with my fuel inject style bike.

The EVAP system on these are added as an afterthought in order to get the bike in to the US. The components do not last forever. You need to plug the nipple off the intake manifold, and run a hose straight down from the gas tank in order to vent it. Hang it on the left side of the bike, away from any source of heat. You can leave the canister, check and follower valves in place, or remove the whole shooting match. Mitch has a good video showing this on a LX150. It would be close to your bike. Will this solve your issue? Maybe, maybe not.

Thanks, I'll pick up a nipple and some extra hose and give it a shot. I like the idea of not removing everything in case it doesn't work or if I sell it someday.

So, I cut the tube running to the intake manifold and capped it. Then removed the end from the canister that leads to the fuel tank, so it can vent. I'll get a coupler and run it down the frame safely next. Still having issues with idle on startup 😔

I disconnected the battery to reset the ECU and I'll try it again tomorrow and also begin a 15 min idle relearn. I guess there could be residual fuel in the line I capped, or it could be something else. Stay tuned…

Well, I'll post the conclusion in case it's helpful for others. After resetting the ECU and doing a relearn, things are running well! Between the fuel pump assembly replacement and the evap stuff, I think i solved the issue.

How do you reset the ECU and initiate a relearn?

Make sure the battery is disconnected to erase anything saved on the ECU. It might not take super long, but I let it stay disconnected for an hour to be sure. That will erased "learned" settings.

Then connect the battery and make sure when you start the scooter you do NOT use throttle. You let it idle for 15 minutes and it will begin relearning things. If it stalls, keep the key engaged and restart while again not using the throttle. Do this idle process on a cold engine. You can take for a drive and do another idle sit again, but the first time is key.

I'd like to see official Piaggio endorsement of this. I cannot see why disconnecting the battery would erase anything. Surely the ECU doesn't keep its maps in RAM - which would be the only memory that would be erased with lack of power.

I think it's one of those internet myths that somehow live for ever.

Many modern Vespa/Piaggio scooters use ECUs from mfg companies like magneti marelli, mikuni, or efi technology.

These ECUs typically have non-volatile memory that stores long-term fuel trims and other data, but some data is lost when power is cut for extended time or reset by diagnostic tools. The longer length of battery disconnect is needed for discharging capacitors.

Workshop manuals imply this, but you're right, they don't call it out specifically. I can say anecdotally, letting things idle without throttle can help improve this and it would align to what many scooter/motorcyles do.

Having looked into resetting ECUs recently, I believe Jim is correct. Piaggio PADs and GuzziDiag have a function for resetting adaptive parameters to default. If simply disconnecting the battery worked, we wouldn't need a software process.

Well, if you ever disconnected your battery for an extended time, you often notice idling it a bit will improve stability. So, something is happenning. Worth a try if you want to avoid a dealer bill. My directions are how most scooters typically work, and I live hours away from a dealer so need to do everything myself.

correct and correct with the GTS with Marelli MIU1/MIUG3/G4. (Not sure what a Liberty has but expect same results).

I have downloaded the 8KB eeprom from mine and mapped out the adaptive / self learning parameters (shown in a different thread). I then disconnected the battery for an hour and reconnected and downloaded again. As expected it had not reset. I used my obdstar (it can do special piaggio cmds) to reset the params and then downloaded the eeprom again and yes it had reset it.

As to idling to make the bike happier ... Basically yes. The adaptive params continuously update for the entire life of the bike regardless of resetting the ecu. Any time that the tps and rpm are stable then the adaptive will slowly adjust itself. (they are also for a whole range of combos of tps vs rpm, not jsut idle). Also note when starting the bike it will run different for the first minute or two because the ecu runs a different map during warm up, it also ignores the o2 while it warms up.

Well, I stand corrected. There is something I've found that improves the adapting (not reset) with battery disconnecting. But, I believe you that's it's not a true reset. I wish Piaggio made it easier to do basic stuff…

Wondering here...
Before purchasing a new fuel pump - did you check the valves - and did you try a new Iridium NGK (not Denso - for some reason the correct Denso iridium didn't have the same very healthy idle as the NGK iridium)

In both of my scooters I found that the NGK iridium made my scooter idle increase a few rpm's - which was reassuring to me as I sat in that monster 15 lane stop-light intersection surrounded by grumpy F-150's and soccer mom's near home!

My new Burgman would die at that intersection - thrilling!
But my cheap scooters don't.

The real fix came when I finally caved and went to the dealer. They said valves were good. There was a dirty throttle body type code they could read, which is strange as I cleaned the throttle body and it all looked good. Mechanic said it all looked good there too, but he did a TPS sensor reset and an idle re-learn using dealor tools I don't have, and that did the trick.

Can be frustrating when you can do a lot of this stuff DIY, but the sensors/computer stuff require dealer tools. Nice thing was the cost wasn't too bad to get done. Ran great after that.

Thanks for the up-date!
I'm relying on my limited skills to sort things on my Liberty - bought it at a Vespa dealer 35 mins away. He was cleaning up after a small tornado strike as I purchased my Liberty.
In spite of his assurances - he closed his doors a few weeks later!
Honestly - never understood his business plan - "let's open a Vespa dealership out in the sticks of Ohio!"

That was 8 yrs ago.
Heck, if it blew up tomorrow - I figure I have had my money's worth of fun with it.
I'd drive a couple hours and bring home another one - but not the ugly '25/'26 model with those LEDs. Design is a mistake!

anyway - has been a flawless runner since the summer of '17!
O.S.

I agree on the ugly led light on the new Liberty. I put led bulbs in the halogen sockets for my old Liberty 50 and 150 and they were great, and look a lot better than the sci-fi new ones.

I just sold my Liberty the other week. Sad to let her go, but I've been happy with my new bv400. I'm out in the country a bit and it's been nice to have something with a little more power for longer drives across town. It is bigger than Liberty, but I still feel like it's not a huge maxi, still fairly nimble.

My dealer is an hour away, not great, but doable. Great thing is the BV has really nice long maintenance intervals to keep that at a minimum.

Well good for you!
My first choice would have been the Beverly 250 back in the day - but not sold here. And I might not have been able to live with its seat that forces the rider forward. I love the 'bench' seat on the Liberty, so I can scoot back to deal with being 6'3". I actually helped unbox my Liberty and trial sat the seat while it was still strapped to the wooden shipping. They were busy and we opened cartons until finding the red one I wanted - but told them I could not buy any scooter that I haven't sat on - so we'll need to keep uncrating far enough for me to throw a leg over. They did, I did = this works! -- and wrote them a check!

A question - which LED did you install in your Liberty - and most importantly - did it give a usable pattern at night?!

Thanks, and ride safe!

O.S.

I was really happy with my LED bulb results. I didn't even mess with headlight trim. I think they have a new model as I can't find the exact one I got. But, here's a snippet of the amazon one I ordered.

The big watch out for this one is the "tabs", there's like 3 of them that rotate to lock it into the socket, and they are fatter than the halogen one. So, I had to be really careful installing it not to break anything. I got it in without breaking things but it was really tight.

Afterwards, it just worked and WAY brighter than stock light. I felt very comfortable riding in the dark with it.