Modern Buddy

Not sure if this is normal, but occasionally, but scooter's idle has been acting up. Idling poorly and then hesitating when given throttle. In most of these cases the engine light comes on, often before the engine is even turned on.

We have wild temperature swings in DC and I have noticed this happens if it is cool one day and then suddenly gets very hot and humid the next. An ECU reset always fixes the problem. The engine runs a bit loud while it tries to recalibrate itself but the engine light stays off and the acceleration is very responsive. At least until the next cold-to-hot swing. I have my valves checked every time I have service done and they have never needed adjusting (although the mechanic always tunes them anyway since he's already in there at this point).

I'm assuming this is not a big deal but it's a bit nerve-racking to see that red light come on.

I always thought modern FI systems were self calibrating regardless of environmental conditions? At least the system in my 1997 GMC van is...

It's been a long time since I owned a Vespa, but back then some Cannonball folks claimed that resetting the ECU was the best way to deal with very large altitude changes. I guess it couldn't hurt as long as you are careful. YMMV.

P.S. I'm with babblefish, I want it to automatically recalibrate on every startup.

I would think that in a closed loop system which all modern FI systems should be, the ECU would be constantly looking at the air/fuel ratio to make sure it's correct and adjust fuel flow if it isn't.

I think you may have gone one assumption too far with the closed loop thing. That requires a lambda probe and I don't think the bike in question has one.

It was is a bit concerning but, like I said, an ECU reset completely fixes the problem. I can't bring the scooter to the shop if the engine works.

You should probably check for corrosion in the socket to the ECU, and at the stator connection. Methinks you have a connection that is going screwy with the humidity. De-Oxit spray, and dielectric grease to the rescue.