whistling noise from new exhaust (and few other problems - newbie) - The Unofficial BMW M5 Messageboard (m5board.com)

christophert21 · 7th August 2009, 01:19

hey. i'm from the uk and got my first e39 m5 last week

i got an exhaust system made and installed today by powerflow (i know i should have waited on a h&S or tubby, but i couldn't wait). now after about 30 miles, when i give it WOT in 2nd gear i get a whisling noise (like a screwed turbo on a turbo diesel).
i'm just wondering could this be a blowout in the exhaust? or could it have blown the insides of the poor quality muffler?

also when i give the throttle a sharp 'blip' i get a 'off cylinder' rev. like as if not in sync. is this just normal characteristics of a v8? yet if i build the revs steady all seems and sounds fine.

sometimes the car feels great and fast, yet at times it can feel slow. i've done the maf test and got a reading of 121 at WOT in 3rd gear.

i tried my cheap code reader to see if any error codes were present but it would not connect so i don't know if i've any error codes

many thanks in advance

Mfreakin5 · 7th August 2009, 05:41

is that 121 MAF number corrected or raw? If it's corrected then your MAF's need to be replaced soon. The noise you hear could just be the normal exhaust sound or could be some of the baffling burning off...give it a few hundred miles.