Strange idle on 2018 328d.

eugene89us · 10-26-2018, 09:33 AM

Good morning, N47 owners!

Wanted to inquire about a strange idle I have noticed on my 2018 328d. I think it has not changed since car was brand new, and now has only 13,000 miles.

When I come to a complete stop, especially when engine in cold at the first traffic light from home, the engine vibrations (minimal) seems to be "wavy." What I mean by that, is that the engine sounds like it is slightly louder every second - wroom, wroom, wroom. You could also feel that vibration is slightly more when it does it. It is very minimal and you can only hear it with radio completely silent. Then it warms up, and the vibrations are consistent. Also noticed only at that traffic light - nowhere else - when I come to a complete stop, the engine may one time drop RPM by about 50 rpm and back up. So I can't really say it has rough idle, but maybe some component comes on as the temp gauge starts to move, which temporarily leads to RPM drop and it catches back up immediately. But I find small wroom, wroom variation to be strange. No codes, of course, so BMW won't do anything since they will not reproduce it unless you take the car cold from my house in the morning.

Any suggestions or confirmations of normality? No other issues, no sluggishness, car is very solid and responsive.

FaRKle! · 10-26-2018, 11:45 AM

Mine does this too when cold.

10-26-2018, 09:33 AM	#1
eugene89us First Lieutenant 336 Rep 365 Posts Drives: 2018 BMW 328d Join Date: Dec 2017 Location: MS iTrader: (0)	Strange idle on 2018 328d. Good morning, N47 owners! Wanted to inquire about a strange idle I have noticed on my 2018 328d. I think it has not changed since car was brand new, and now has only 13,000 miles. When I come to a complete stop, especially when engine in cold at the first traffic light from home, the engine vibrations (minimal) seems to be "wavy." What I mean by that, is that the engine sounds like it is slightly louder every second - wroom, wroom, wroom. You could also feel that vibration is slightly more when it does it. It is very minimal and you can only hear it with radio completely silent. Then it warms up, and the vibrations are consistent. Also noticed only at that traffic light - nowhere else - when I come to a complete stop, the engine may one time drop RPM by about 50 rpm and back up. So I can't really say it has rough idle, but maybe some component comes on as the temp gauge starts to move, which temporarily leads to RPM drop and it catches back up immediately. But I find small wroom, wroom variation to be strange. No codes, of course, so BMW won't do anything since they will not reproduce it unless you take the car cold from my house in the morning. Any suggestions or confirmations of normality? No other issues, no sluggishness, car is very solid and responsive.
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10-26-2018, 11:45 AM	#2
FaRKle! Brigadier General 4016 Rep 3,539 Posts Drives: 328d Wagon, M2 Comp, i4 eD35 Join Date: Sep 2016 Location: Bay Area, CA iTrader: (4) Garage List 2023 BMW i4 eDrive 35 [0.00] 2017 BMW 328dx Wagon [0.00] 2021 BMW M2 Competi ... [0.00]	Mine does this too when cold.
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