oscarleo

Second time I've asked this question - I know at cold start our cars idle around 1,500 RPM for maybe a minute to warm pollution control equipment. My issue is my 2024 450 idles at the cold start RPM level even when it's been running and warm, then off for a half hour or so. And this is in FL weather. Took to dealer and they said it's the new normal for '24's as they tested other '24 450's they had in inventory. Just does not seem right to me. Never had this issue with 2020 450, or 2012 ML 350. Not a huge deal, but annoying as I have to wait for RPM's to come down after almost every start.

streborx

Just because other inventory behaves the same way doesn't make it normal. All it means is they all have the same software that could be wrong. Idling at 2x the normal RPM seems abnormal to me -- this would result in more emissions, not fewer. But who knows -- there are probably several sensor inputs that determine the idling RPM, and the software might not have been thoroughly tested. Maybe the dealer can pass the complaint along to MB.

mikapen

How long?
Sounds normal, and you're right that it's designed to fire off the catalytic converter. Which is immediately downstream of the turbo.

30 seconds would probably be acceptable. Two minutes, probably not.

jonpom

When I restart my 24 GLE53 while warm, it starts so instantaneously that I have to check tach to be sure it indeed is running. And continues to run at normal RPM until I shut it off.

Fiodar

I have same issue with the brand new 2024 GLE 63s. I owned 2021 GLE 63s right prior and revs came down relatively quickly when engine was warm, and no more than 30-45 sec on cold.
About to check it with dealer. It's not feeling normal to me either.

taphil

My 2021 E63s revs come down within a minute, but the 2024 GLE63s takes a few minutes. I guess it's normal.

oscarleo

Let me know what your dealer tells you. Thanks.

parato

One more reason to love my GLE 450e. Zero RPM on startup and for the first 60 miles of driving.