N53 Croaking Frog/ Screeching in Stratified Charge Mode

0l0dom0l0 · 07-26-2022, 10:26 AM

Has anyone has been able to fix this issue on an N53 by fitting what I believe is a revised return fuel pipe from the HPFP?

For about the last 18 months, my car has been running homogenous mode as I have the NOX cat aging fault. I've replaced the NOX sensor and registered a new NOX catalyst to return the car to running stratified mode. However, I have a screeching sound, which sounds like the aux belt is gone, but when the car is running in stratified charge mode ONLY. It sounds the worst just above idle but can be heard at all low speeds with the windows down etc. I forgot how bad and annoying it is.

I'm pretty sure this is a known issue which is why my question is quite specific to fitting the updated part which is meant to make this better, however I'm also curious to hear if anyone has done anything else to rectify it and also heard that the revised part has not made any difference.

Phil325i · 07-26-2022, 11:17 AM

Could it be your PCV? The only other case of 'croaking' I've heard of was linked to that. Try removing your oil filler cap with the engine running. If you get massive resistance and a huge vacuum, that could indicate your problem...

Dormermike · 07-26-2022, 11:29 AM

+1 to CCV

0l0dom0l0 · 07-26-2022, 02:23 PM

It's not the CCV, I've checked it

It happens only when the car is running stratified charge mode - you can see it in carly.

Took me about 2 months to narrow the issue down when I first noticed it. I went through everything.

Dormermike · 07-26-2022, 03:17 PM

So where is the noise actually coming from, you mean you've narrowed it to fuel pipes or the fuel rail atop the engine?

07-26-2022, 10:26 AM	#1
0l0dom0l0 First Lieutenant 71 Rep 318 Posts Drives: BMW E92 330i Join Date: Jun 2020 Location: Uk iTrader: (0)	N53 Croaking Frog/ Screeching in Stratified Charge Mode Has anyone has been able to fix this issue on an N53 by fitting what I believe is a revised return fuel pipe from the HPFP? For about the last 18 months, my car has been running homogenous mode as I have the NOX cat aging fault. I've replaced the NOX sensor and registered a new NOX catalyst to return the car to running stratified mode. However, I have a screeching sound, which sounds like the aux belt is gone, but when the car is running in stratified charge mode ONLY. It sounds the worst just above idle but can be heard at all low speeds with the windows down etc. I forgot how bad and annoying it is. I'm pretty sure this is a known issue which is why my question is quite specific to fitting the updated part which is meant to make this better, however I'm also curious to hear if anyone has done anything else to rectify it and also heard that the revised part has not made any difference.
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07-26-2022, 11:17 AM	#2
Phil325i Brigadier General 639 Rep 3,212 Posts Drives: E92 325i MSport Coupe Join Date: Apr 2012 Location: UK South East iTrader: (1) Garage List 2009 BMW 325i Coupe [6.00]	Could it be your PCV? The only other case of 'croaking' I've heard of was linked to that. Try removing your oil filler cap with the engine running. If you get massive resistance and a huge vacuum, that could indicate your problem... __________________ E92 pre-LCI 325i - Ohlins R&T; H&R spacers; M3 strut brace; Swift thrust sheets; 3 x chassis braces; diff brace; N53 V-brace; 034 subframe inserts; BMS clutch stop; BMS CDV; RE g/box mounts; Delrin shift bushes; Saikoumichi OCC; Cyba scoops; BMW Perf Exhaust; HEL s/steel brake hoses; M3 rear spoiler; Recaro Sportster CSs; M3 white dash LEDs; LED Angels; LED side repeaters; BMW Perf black grille; CSL reps; SSDD carbon diffuser; Monster Wrap black roof/clear front
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07-26-2022, 11:29 AM	#3
Dormermike Captain 104 Rep 674 Posts Drives: Bmw f10 Join Date: Dec 2015 Location: Uk iTrader: (0)	+1 to CCV
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07-26-2022, 02:23 PM	#4
0l0dom0l0 First Lieutenant 71 Rep 318 Posts Drives: BMW E92 330i Join Date: Jun 2020 Location: Uk iTrader: (0)	It's not the CCV, I've checked it It happens only when the car is running stratified charge mode - you can see it in carly. Took me about 2 months to narrow the issue down when I first noticed it. I went through everything.
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07-26-2022, 03:17 PM	#5
Dormermike Captain 104 Rep 674 Posts Drives: Bmw f10 Join Date: Dec 2015 Location: Uk iTrader: (0)	So where is the noise actually coming from, you mean you've narrowed it to fuel pipes or the fuel rail atop the engine?
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