M550 strange noise from under car

G30EPE · 07-27-2023, 02:33 PM

Hi All. New guy here. Been on many bimmer forums for decades. Just new to here.

So I just bought a 2020 M550. It has some strange noises coming from under the car in the rear. Small high speed motor noise. Maybe from between the rear wheels or just aft of the rear wheels. I've attached a YouTube video with car running.

Also, when the car wakes up from sleep mode it has a similar (maybe the same) high pitched small motor noise.

Thanks for any thoughts.

https://youtu.be/0OAm40KNXMs

weinerbarn · 07-27-2023, 03:23 PM

Quote:

Originally Posted by G30EPE

Hi All. New guy here. Been on many bimmer forums for decades. Just new to here.

So I just bought a 2020 M550. It has some strange noises coming from under the car in the rear. Small high speed motor noise. Maybe from between the rear wheels or just aft of the rear wheels. I've attached a YouTube video with car running.

Also, when the car wakes up from sleep mode it has a similar (maybe the same) high pitched small motor noise.

Thanks for any thoughts.

It could be the fuel pump in the tank. There's an access panel under the rear seat, right side.

adhrp · 07-27-2023, 04:29 PM

High pitched sound upon wake up is definitely the low pressure fuel pump, however it doesn't sound like any of your videos. It's more like a whining noise. If you're hearing that, it is a sign that it's failing... Get it changed before it fails.

G30M · 07-27-2023, 04:42 PM

also make sure to replace fuel filter maybe it's blocked causing fuel pump failing

G30EPE · 07-28-2023, 07:39 AM

Thanks for replies. Actually both of those videos are the same. Not sure why it posted twice. I'll get a video of the high pitched motor wine on wakeup when I get home Monday. I'll post it then.

G30EPE · 07-31-2023, 07:54 AM

This is the loud noise on wakeup after sitting for a few hours.

https://youtu.be/Ug2sG8suyTQ

Anyone hear anything like that everything you walk up to car and unlock it? Not on short stops but pretty much every time if left sitting for a few hours.

Thanks for replies.

adhrp · 07-31-2023, 08:03 AM

Quote:

Originally Posted by G30EPE

This is the loud noise on wakeup after sitting for a few hours.

https://youtu.be/Ug2sG8suyTQ

Anyone hear anything like that everything you walk up to car and unlock it? Not on short stops but pretty much every time if left sitting for a few hours.

Thanks for replies.

Yup, typical low pressure fuel pump failing noise. Had it on my car a few months ago. It ended up failing and causing my car to shudder and shut down one day as soon as I hit the ignition. Take it in to the dealership if still under warranty and it should be covered like mine was, but get it replaced soon either way.

Joe-BMW33 · 07-31-2023, 09:28 AM

Quote:

Originally Posted by adhrp

Yup, typical low pressure fuel pump failing noise. Had it on my car a few months ago. It ended up failing and causing my car to shudder and shut down one day as soon as I hit the ignition. Take it in to the dealership if still under warranty and it should be covered like mine was, but get it replaced soon either way.

You sure that sound isn't the active grills opening and closing?

adhrp · 07-31-2023, 11:03 AM

Quote:

Originally Posted by Joe-BMW33

You sure that sound isn't the active grills opening and closing?

I'm sure. I haven't heard the active grills opening/shutting (are you talking about the first video or the one posted today?). I'm talking about the one posted today...it is the unmistakeable sound of a failing LPFP.

Joe-BMW33 · 07-31-2023, 11:18 AM

Quote:

Originally Posted by adhrp

I'm sure. I haven't heard the active grills opening/shutting (are you talking about the first video or the one posted today?). I'm talking about the one posted today...it is the unmistakeable sound of a failing LPFP.

I was referring to the second video of the car waking up. Just a thought, you would know better than I. I always thought that vacuum sound was the shutters cycling.

tjbuggy2b · 07-31-2023, 11:25 AM

Second video is def LPFP priming the system. Guessing the first video is the same thing, just... you know, running. lol

If it's that loud, definitely get it replaced.

Joe-BMW33 · 07-31-2023, 11:33 AM

Quote:

Originally Posted by tjbuggy2b

Second video is def LPFP priming the system. Guessing the first video is the same thing, just... you know, running. lol

If it's that loud, definitely get it replaced.

You learn a new thing every day. I always thought this sound was the active grill.

adhrp · 07-31-2023, 11:56 AM

Quote:

Originally Posted by Joe-BMW33

You learn a new thing every day. I always thought this sound was the active grill.

Yeah when I bought the car it already had the sound so I didn't know that it was not a good sound to have, but I did wonder why it was that loud...seemed a bit odd. Fast forward a couple of months later and the LPFP failed, dealership replaced it under warranty and now the LPFP priming is down to a whisper.

OP will be best served to take it into the dealership if the car's still under warranty, considering that a 2020 model will be out of the original warranty period soon.

G30EPE · 07-31-2023, 01:36 PM

Thanks for the replies. I sort of suspected a fuel pump of some sort.

Not to sound inept...but what are the grills that cycle?

Still under warranty for 9 months or so.

tjbuggy2b · 07-31-2023, 02:03 PM

Quote:

Originally Posted by G30EPE

Thanks for the replies. I sort of suspected a fuel pump of some sort.

Not to sound inept...but what are the grills that cycle?

Still under warranty for 9 months or so.

There are louvres in the kidney grills that open automatically. Though, unless there is something really wrong with them, you aren't going to hear them at the back of the car.

Next time you cold start it, run up and look at the grill. You can sometimes get there in time to see them open.

(To be fair, I don't know if all trims have this.)

G30EPE · 07-31-2023, 02:07 PM

I'm guessing my car has the active grills because they always appear closed when car is off. I was wondering if they were automatic or the cooling airflow came from somewhere else.

Thanks a lot. Have a lot to learn about this technological beast.

G30EPE · 08-03-2023, 05:29 PM

Update. BMW is replacing LPFP under warranty. Thanks to all.

Johnkwick · 12-03-2023, 05:21 AM

Hi, did you experience any symptoms from the failing LPFP? Like long start-up crank, drivetrain malfunction, etc etc? Or was it just the humming noise?

Drifttime85 · 12-03-2023, 10:22 AM

I just got into a Beemer for the first time this year but working on my previous cars and upgrading fuel pumps in the past, the sound reminds me of what I hear in your video.

07-27-2023, 02:33 PM	#1
G30EPE New Member 14 Rep 20 Posts Drives: BMW M550 Join Date: Jul 2023 Location: NE PA iTrader: (0)	M550 strange noise from under car Hi All. New guy here. Been on many bimmer forums for decades. Just new to here. So I just bought a 2020 M550. It has some strange noises coming from under the car in the rear. Small high speed motor noise. Maybe from between the rear wheels or just aft of the rear wheels. I've attached a YouTube video with car running. Also, when the car wakes up from sleep mode it has a similar (maybe the same) high pitched small motor noise. Thanks for any thoughts. https://youtu.be/0OAm40KNXMs
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07-27-2023, 04:29 PM	#3
adhrp Lieutenant Colonel 1318 Rep 1,638 Posts Drives: 2020 M550i (G30)/2021 X3 (G02) Join Date: Jun 2014 Location: FL iTrader: (0)	High pitched sound upon wake up is definitely the low pressure fuel pump, however it doesn't sound like any of your videos. It's more like a whining noise. If you're hearing that, it is a sign that it's failing... Get it changed before it fails. __________________ 2020 M550i (G30) \| Carbon Black/Black Nappa \| DHP \| DAP \| Executive \| Luxury Seating \| Park Asst \| Ceramic Controls \| Front/Rear Heated Seats \| 20" 668M wheels 2021 X3 (G02) \| Dark Graphite Metallic/Cognac \| Premium \| DAP \| Front/Rear Heated Seats Sold/Retired: 2012 328i (F30) Last edited by adhrp; 07-31-2023 at 03:03 PM.. Reason: typo
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07-27-2023, 04:42 PM	#4
G30M Brigadier General 3821 Rep 4,166 Posts Drives: BMW M550i; Kia EV6 GT Join Date: Dec 2021 Location: Australasia iTrader: (0)	also make sure to replace fuel filter maybe it's blocked causing fuel pump failing
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07-28-2023, 07:39 AM	#5
G30EPE New Member 14 Rep 20 Posts Drives: BMW M550 Join Date: Jul 2023 Location: NE PA iTrader: (0)	Thanks for replies. Actually both of those videos are the same. Not sure why it posted twice. I'll get a video of the high pitched motor wine on wakeup when I get home Monday. I'll post it then.
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07-31-2023, 07:54 AM	#6
G30EPE New Member 14 Rep 20 Posts Drives: BMW M550 Join Date: Jul 2023 Location: NE PA iTrader: (0)	This is the loud noise on wakeup after sitting for a few hours. https://youtu.be/Ug2sG8suyTQ Anyone hear anything like that everything you walk up to car and unlock it? Not on short stops but pretty much every time if left sitting for a few hours. Thanks for replies.
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07-31-2023, 11:25 AM	#11
tjbuggy2b Lieutenant 186 Rep 418 Posts Drives: 2018 540i xDrive M Sport Join Date: Nov 2010 Location: Columbus, OH iTrader: (0)	Second video is def LPFP priming the system. Guessing the first video is the same thing, just... you know, running. lol If it's that loud, definitely get it replaced.
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07-31-2023, 01:36 PM	#14
G30EPE New Member 14 Rep 20 Posts Drives: BMW M550 Join Date: Jul 2023 Location: NE PA iTrader: (0)	Thanks for the replies. I sort of suspected a fuel pump of some sort. Not to sound inept...but what are the grills that cycle? Still under warranty for 9 months or so.
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07-31-2023, 02:07 PM	#16
G30EPE New Member 14 Rep 20 Posts Drives: BMW M550 Join Date: Jul 2023 Location: NE PA iTrader: (0)	I'm guessing my car has the active grills because they always appear closed when car is off. I was wondering if they were automatic or the cooling airflow came from somewhere else. Thanks a lot. Have a lot to learn about this technological beast.
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08-03-2023, 05:29 PM	#17
G30EPE New Member 14 Rep 20 Posts Drives: BMW M550 Join Date: Jul 2023 Location: NE PA iTrader: (0)	Update. BMW is replacing LPFP under warranty. Thanks to all.
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12-03-2023, 05:21 AM	#18
Johnkwick Private 24 Rep 94 Posts Drives: F10 LCI Join Date: Mar 2020 Location: Southern Nusa Dua, Bali iTrader: (0)	Hi, did you experience any symptoms from the failing LPFP? Like long start-up crank, drivetrain malfunction, etc etc? Or was it just the humming noise?
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12-03-2023, 10:22 AM	#19
Drifttime85 Private First Class 107 Rep 144 Posts Drives: BMW M550i Join Date: Jun 2023 Location: Atlanta iTrader: (0)	I just got into a Beemer for the first time this year but working on my previous cars and upgrading fuel pumps in the past, the sound reminds me of what I hear in your video.
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