Modern Vespa

I have a sick MP3 250 and was trying to rig up some software to connect to my ECU and read the CEL code(s).

I can't seem to find the ODB plug. I found pictures that looked like it was near the edge under the seat access port.

Symptoms I am dealing with:
It ran fine all summer but when the temperatures dropped it won't start/idle. I think winter killed the battery so I could use suggestions there as well.

My plan is to clean the throttle body, use some sea foam and swap the battery out. Then see what the ECU is telling me and go from there.

I am a new MP3 mechanic but I have tools etc from maintaining and working on cars much of my life.

Thanks!
Rusd

I would start by checking the battery. Below 11.5V you will have issues.

I measured it today, and it is 12.2v ish (fluctuates)

If I flip the starter though it drops to 9-10 and cranks pretty slowly so I am pretty sure it isn't happy.

Is there a battery that everyone loves on here for these things?

Thanks
Russ

A healthy battery should read between 12.6-12.8V with no load after sitting overnight. But a battery tester is the better judge, I use this one as it also tests the starter and charging systems.

https://www.amazon.com/FOXWELL-BT705-Automotive-100-2000-Cranking/dp/B01ANF1D7U/ref=sr_1_1_sspa?crid=39DGT38XOURN5&keywords=foxwell+battery+tester+bt705&qid=1581416087&sprefix=foxwell+batt%2Caps%2C224&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzVkQwSVowTU9COVVEJmVuY3J5cHRlZElkPUEwMjE4MjQyMUlJUTNGTjIwNFI3RiZlbmNyeXB0ZWRBZElkPUEwNjk1NjIzMkg2Q0dOWk5KREJSRCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

The diagnostic plug is located next to the battery

One more thing, Yuasa YTX14H-BS AGM battery for the win. The H denotes the high performance variant with at least 10% more cranking power over the standard battery.

As an upgrade, you can install the Yuasa GYZ16H but the price is almost double over the standard YTX14

Just be sure to follow these 3 simple steps for longest battery life prior to installing. 1) After adding the acid pack, let the battery sit for 1 hour without pressing in the capstrip. 2) After 1 hour has passed, press in the capstrip. 3) Recharge the battery using a 1Amp smart charger (such as Optimate 4) overnight or about 12 hours whichever comes first.

If the bike is going to sit for more than a week, hook it up to a smart charger. I prefer the Optimate 4 since they automatically disconnect when fully charged and reconnect periodically to test and top off the battery. No worries about the battery going stale due to being on the trickly charger long term.

https://www.yuasabatteries.com/battery/ytx14-bs/

https://www.yuasabatteries.com/battery/gyz16h/

I swore I had checked there when I hooked up my tender wires, but I will certainly look again.

Thnaks!

Scooterwest use to sell the Diagnostic Tool that Plugs into the ODB plug and software; you would use your Computer.

I had an interest a few years ago and thought it would be good to have with all my other Scooter Tools, and it would also work on my Vespa.

I later found out it was better to go to the Dealer, as they get all the updates from Piaggio. You could only Read the Codes, the Dealer can actually update the bikes Firmware and you can't.

My MP3/250 has been updated twice and it seems to run much better with the LeoVince Exhaust.

Keith,
Marietta, GA

Replace the battery and all you trouble will stop.

I have and great success with these batteries.

https://amazon.com/gp/product/B003YMRH70/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

I am kind of amazed. I replaced the battery and like magic the bike runs and idles great.


I still have to chase down what the check engine light is, but I have the cables and now know where the obd plug is at, so with a little luck and some free software I should be able to read that.

Then... I need to figure out why the headlight stopped working. Bright still works, that may just be a switch issue.

I will keep posting replies as I journey through the problems of this bike. It is so nice to be able to ride it again though.

If anyone knows where to get a key fob for one of these it would be nice not to have to reach under the seat to unhook the main cubby. The bike only came with the red key though.

(so many little issues)