Our 03 Prius has one odd quirk. If anyone knows why it may be doing this, please post any comments. When returning home, the car is usually in electric mode and stays that way until it's parked. Then, just as I turn the key off, the engine starts up. When the key is all the way off, it stops, and has run about two or three revolutions at the most. I'm pretty sure the battery is not due for recharging - the car is in all-electric mode because our final approach is all downhill, and the car has been in regenerative charge mode for several minutes. Any ideas?
That car just wants to go out more! It's just trying to say, "Ah, c'mon. Don't shut me off yet, I want to drive some more." I had a car some time ago that was like this. When I shut it off, it would knock around for a little while trying to coax me back in for some more driving.
The '01-'03 Prius has an HC absorbing catylitic converter. In order to burn off the HC's that were absorbed, the engine must start and run briefly to keep things hot enough and to burn off the HC's so they're released as CO[sub:90eecb1833]2[/sub:90eecb1833] and H[sub:90eecb1833]2[/sub:90eecb1833]O vs. whatever the unburned HC's comprise of. Some call it general housekeeping. It's typically triggered when the car is put into park. If you don't let it run, it's okay, it will simply "be continued" the next time the car is started. The '04 Prius doesn't have this catylitic converter, but instead the thermos system, so we don't experience this same phenomenon. BTW - this cat did make it on the '04 Camary with the PZEV rating. BTW - this topic probably belongs in troubleshooting, etc - not performance mods.
perfectly normal on a Classic. If the ICE temp is above 70C and the battery state of charge is over 60%, the ICE will only run for about 10 seconds if the two above paramaters are lower than observed above it will run longer to get to that limit or close to it. The ICE is more sensitive to temperature than any other paramater.