Honda Sh150i 2010 when warm stall at idle

[martinklie]

Hi All,

I have a 2010 Honda Sh150i scooter with ~4500 miles with a stall issue. It happened once last year and though nothing of it but this year its consistent. It will stall at idle when warm. I say specifically warm because it will only stall then the temperature gate is above 1/4 hot ~ 140 deg F and just below 1/2 hot ~ 175 deg F (used a temperature gauge reading from the water pump). If running on the open road at these temps it will run fine. Once you get to operating temp it will idle all day long ~ 180 deg F. It only happens inside those temperature ranges and only at idle (stopping in traffic as an example). If I hold the throttle above idle I can prevent it from stalling. If it does stall I can easily restart it but need to gas it right away and move otherwise it will stall again.

I have changed the plug and air filter for new. Drained the fuel tank and put in new gas with fuel injector cleaner. Changed the oil ~ 1000 miles ago. New battery 2 years ago. Order the shop manual in hopes of finding next steps.

Cant find anything like this in searched. Open to anyone's suggestions. Thanks in advance for your feedback.

[TommyXP]

From the Factory Service Manual:
TROUBLESHOOTING-
Engine Stall, hard to start, rough idling:
*Intake air leak
*Fuel contaminated/deteriorated
*Pinched or clogged fuel feed hose
*Faulty IAC valve in the ECM

Your obtaining the Factory Service Manual will be a big help.....
My only thought is to check the idle RPM setting maybe......

[martinklie]

Thanks for the info. I received the service manual and jumped the brown a green wire together to get a 1-2 MAP sensor circuit code. The manual suggested to clear the code which I think I did properly. After running a bit it stalled again. Now though the MIL is stays lit which after going through the codes looks to point to a faulty ECM.

If possible can anyone with a working scooter read the DTC with the MIL using the SCS connector or jumper. Hoping to see what a happy scooter shows. Thanks in advance.

[TommyXP]

I have no experience with this, though it has been discussed in a number of past topics (search function) of which this is only one which might give you something to chew on:
viewtopic.php?f=12&t=1650&hilit=code+map+blink

[martinklie]

Summary: The plug used to originally replace the plug was bad. Just put in a new one yesterday and we had two successful trips with no stalling. Will buy Honda parts from now on. I should know better as this bit me once with my Prelude.

Hope though someone can share what the MIL lights will show when all is fine and the SCS connector or jumper is on. Thanks in advance.