My 2019 Honda Pilot with 38000 miles equipped with the Start/Stop feature does not allow that function to operate until the engine is up to normal temperature. Living in the north I see the SS feature begin to work within a few minutes of driving during the summer but could be 5-10 minutes before it starts working during the winter. I leave the feature on year round, do my own oil changes every 5000 miles, and have never noticed any fuel dilution or gasoline smell in the oil I drain out. Oil level is always right on the mark I filled it to during the last change so no fluid being added to the crankcase. YMMV
Same with our Pacifica.
There's a host of criteria that prevent the system from shutting the engine off.
I've personally seen engine too cold, actively cooling (A/C) and steering wheel being turned.
Just looked it up (obviously this covers a range of vehicles, not just the Pac
Stop/Start Ready – If Equipped
Stop/Start Not Ready – If Equipped
Stop/Start Not Ready Hood Open – If Equipped
Stop/Start Not Ready Battery Charging – If Equipped
Stop/Start Not Ready Trailer Tow/Haul Selected – If Equipped
Stop/Start Not Ready 4WD/Low Range Selected – If Equipped
Stop/Start Not Ready Fuel Level Low – If Equipped - (mildly ironic eh?)
Stop/Start Not Ready Steep Incline – If Equipped
Stop/Start Not Ready Extreme Outside Temperature – If Equipped
Stop/Start Not Ready Engine Temperature Too High – If Equipped
Stop/Start Not Ready Engine Temperature Too Low – If Equipped
Stop/Start Not Ready Driver Seatbelt Unbuckled – If Equipped
Stop/Start Not Ready Driver Door Open – If Equipped
Stop/Start Not Ready Cabin Cooling Or Heating – If Equipped
Stop/Start Not Ready Not Ready Max Cooling Or Heating – If Equipped
Stop/Start Not Ready Max Cooling Or Heating Selected – If Equipped
Stop/Start Not Ready Front Defrost Selected – If Equipped
Stop/Start Not Ready Steering Wheel Turned – If Equipped
Stop/Start Autostop Active – If Equipped
Stop/Start To Restart Push Clutch Or Shift To Neutral – If Equipped
Stop/Start Req’d Fault Detected – If Equipped
Stop/Start Cannot Autostart Hood Open – If Equipped
Stop/Start Unavailable Service Battery – If Equipped
Stop/Start Unavailable Service Stop/Start System – If Equipped
Stop/Start To Restart Shift Out Of Park – If Equipped
Stop/Start Off – If Equipped (this would mean that someone pushed the manual deactivate button)