E90 330i exhaust issue?

toryjlarsen · 02-24-2021, 04:00 PM

Hi all, yesterday driving home from work I was getting onto the freeway and as I'm accelerating I heard what I can only vaguely remember as kinda a real quick scrape sound, didn't hit a bump or anything in the road. thought it was from another car passing me by.
As I'm driving I notice it felt like it was slightly sluggish and I could here a slightly lower hum from exhaust then normal.
pulled off in the next exit and waited at the stoplight, then when I went to accelerate I was hearing this louder rattling sound that only happened when accelerating, and also was pretty sluggish when accelerating between 1000-2000rpm, with only a slightly rough idle. Parked the car, left it on and checked under the hood, couldn't hear anything wrong in the engine bay, wife came to pick me up and I had her step on the gas pedal while in neutral and I still couldn't hear the rattling sound in the engine bay. Then realized the sound was coming from under the car towards the back of the engine thinking something with the exhaust.
decided to drive it to her parents house down the road cause I didn't trust driving it farther to get it home. As I'm pulling away I'm still hearing that rattling sound when I am accelerating or decelerating, but not when I'm stopped, when I turn and accelerate onto the main road... the rattling is there then goes away completely. Drove it about a mile to the parents house, still no rattle sound. I parked it and plugged in my schawben scan tool... no codes, still no rattle anymore, give it some revs, and no rattle, but there was still the sluggish behavior at lower RPMs and still that kinda lower hum, almost like the exhaust is being restricted.
I'm waiting for the weekend to drive it about 10 miles back home but I wanted to get any input from my fellow bmw guys here beforehand. Thanks guys!

2006 E90 330i
Manual Transmission
135k miles

freakystyly · 02-24-2021, 04:18 PM

If you can get it lifted.. check #13
https://www.realoem.com/bmw/enUS/sho...diagId=18_0588
regarding the rattle. Mine had it's rattle disappear (and the clamp as well) one day.. the bolt sheared off from rattling about.

You may hear a puffing noise at idle from under your passenger seat if your gaskets are leaking.

toryjlarsen · 02-24-2021, 04:48 PM

Quote:

Originally Posted by freakystyly

If you can get it lifted.. check #13
https://www.realoem.com/bmw/enUS/sho...diagId=18_0588
regarding the rattle. Mine had it's rattle disappear (and the clamp as well) one day.. the bolt sheared off from rattling about.

You may hear a puffing noise at idle from under your passenger seat if your gaskets are leaking.

it's possible, last time I had my car on a lift I remember tightening that #13 down pretty damn good because I had a rattle from that years back, but the rattle I was hearing seemed to be coming closer to the engine than that bracket is.

lowrydr310 · 02-25-2021, 12:24 PM

The noise and rattle sounds like a shield, bracket, or the vacuum-actuated exhaust flapper, however none of those should cause noticeably sluggish performance.

Maybe a piece of one of your catalytic converters dislodged and made its way back to the resonator or muffler? Monitor for codes and see if you get any catalyst efficiency errors over the next few weeks.

toryjlarsen · 02-26-2021, 11:05 AM

Quote:

Originally Posted by lowrydr310

The noise and rattle sounds like a shield, bracket, or the vacuum-actuated exhaust flapper, however none of those should cause noticeably sluggish performance.

Maybe a piece of one of your catalytic converters dislodged and made its way back to the resonator or muffler? Monitor for codes and see if you get any catalyst efficiency errors over the next few weeks.

Yeah thats what I am thinking. I will be going to drive it back to my place tomorrow, then I'm gonna get it on some stands, really wish I had a car lift lol. Used to work at ground control suspension systems where I would have access to a lift whenever I needed it. my best jack stands will have to do haha. Any advice on what part of the exhaust to remove first after monitoring for codes?

toryjlarsen · 02-27-2021, 03:04 PM

Sooo when I got it home I was running it through some diagnosis runs and the sound came back with an absolute vengeance upon revving it up a few times. please check the video out

I know the sound is not coming from the top side of the engine and it is much louder underneath the car.

lowrydr310 · 03-03-2021, 03:36 PM

Looks like the original poster found the source of the problem:

https://www.e90post.com/forums/showthread.php?t=1803291

Not exhaust related. Looks like DMF failure.

02-24-2021, 04:00 PM	#1
toryjlarsen Private 14 Rep 72 Posts Drives: 2006 330i Sedan (E90) Join Date: Jan 2018 Location: California iTrader: (0)	E90 330i exhaust issue? Hi all, yesterday driving home from work I was getting onto the freeway and as I'm accelerating I heard what I can only vaguely remember as kinda a real quick scrape sound, didn't hit a bump or anything in the road. thought it was from another car passing me by. As I'm driving I notice it felt like it was slightly sluggish and I could here a slightly lower hum from exhaust then normal. pulled off in the next exit and waited at the stoplight, then when I went to accelerate I was hearing this louder rattling sound that only happened when accelerating, and also was pretty sluggish when accelerating between 1000-2000rpm, with only a slightly rough idle. Parked the car, left it on and checked under the hood, couldn't hear anything wrong in the engine bay, wife came to pick me up and I had her step on the gas pedal while in neutral and I still couldn't hear the rattling sound in the engine bay. Then realized the sound was coming from under the car towards the back of the engine thinking something with the exhaust. decided to drive it to her parents house down the road cause I didn't trust driving it farther to get it home. As I'm pulling away I'm still hearing that rattling sound when I am accelerating or decelerating, but not when I'm stopped, when I turn and accelerate onto the main road... the rattling is there then goes away completely. Drove it about a mile to the parents house, still no rattle sound. I parked it and plugged in my schawben scan tool... no codes, still no rattle anymore, give it some revs, and no rattle, but there was still the sluggish behavior at lower RPMs and still that kinda lower hum, almost like the exhaust is being restricted. I'm waiting for the weekend to drive it about 10 miles back home but I wanted to get any input from my fellow bmw guys here beforehand. Thanks guys! 2006 E90 330i Manual Transmission 135k miles
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02-24-2021, 04:18 PM	#2
freakystyly Colonel 3753 Rep 2,017 Posts Drives: F22 B58 6MT Join Date: May 2016 Location: Ontario iTrader: (0)	If you can get it lifted.. check #13 https://www.realoem.com/bmw/enUS/sho...diagId=18_0588 regarding the rattle. Mine had it's rattle disappear (and the clamp as well) one day.. the bolt sheared off from rattling about. You may hear a puffing noise at idle from under your passenger seat if your gaskets are leaking.
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02-25-2021, 12:24 PM	#4
lowrydr310 Robot 2278 Rep 2,552 Posts Drives: 2006 330i, 2007 E93 335i Join Date: Apr 2013 Location: Souhtrne Califniora iTrader: (1)	The noise and rattle sounds like a shield, bracket, or the vacuum-actuated exhaust flapper, however none of those should cause noticeably sluggish performance. Maybe a piece of one of your catalytic converters dislodged and made its way back to the resonator or muffler? Monitor for codes and see if you get any catalyst efficiency errors over the next few weeks.
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02-27-2021, 03:04 PM	#6
toryjlarsen Private 14 Rep 72 Posts Drives: 2006 330i Sedan (E90) Join Date: Jan 2018 Location: California iTrader: (0)	Sooo when I got it home I was running it through some diagnosis runs and the sound came back with an absolute vengeance upon revving it up a few times. please check the video out I know the sound is not coming from the top side of the engine and it is much louder underneath the car.
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03-03-2021, 03:36 PM	#7
lowrydr310 Robot 2278 Rep 2,552 Posts Drives: 2006 330i, 2007 E93 335i Join Date: Apr 2013 Location: Souhtrne Califniora iTrader: (1)	Looks like the original poster found the source of the problem: https://www.e90post.com/forums/showthread.php?t=1803291 Not exhaust related. Looks like DMF failure.
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