Z Shift BOV problem high pitched whistle

335icopeman · 10-15-2009, 06:55 PM

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Terrance28 · 10-17-2009, 08:53 PM

Maybe it is your brake pads. Are you on the gas when this happens?

supahdave · 10-18-2009, 02:13 AM

The BOV could be fluttering. Is there an adjustment knob on the BOV?

The spring could have weakened a little bit. Once vacuum is applied and allowed opening of the BOV, the spring might not have enough tension to keep the valve closed after boost relief, causing it to inadvertantly open a slight amount.

2 cars ago, i had to adjust mine a few times to get it right, so its just a thought.

10-15-2009, 06:55 PM	#1
335icopeman Captain 80 Rep 928 Posts Drives: M5 Join Date: Feb 2007 Location: DTLA iTrader: (3)	. . __________________ Last edited by 335icopeman; 07-20-2010 at 04:03 AM..
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10-17-2009, 08:53 PM	#2
Terrance28 Brigadier General 109 Rep 3,334 Posts Drives: Crimson Red E92 Join Date: Nov 2007 Location: Killeen, TX iTrader: (17)	Maybe it is your brake pads. Are you on the gas when this happens? __________________ Mods list got too long, lets just say more than enough.
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10-18-2009, 02:13 AM	#3
supahdave Lieutenant 24 Rep 563 Posts Drives: 09 AW 335i Sedan Join Date: Feb 2009 Location: San Diego, CA iTrader: (4)	The BOV could be fluttering. Is there an adjustment knob on the BOV? The spring could have weakened a little bit. Once vacuum is applied and allowed opening of the BOV, the spring might not have enough tension to keep the valve closed after boost relief, causing it to inadvertantly open a slight amount. 2 cars ago, i had to adjust mine a few times to get it right, so its just a thought.
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