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10-09-2019, 06:36 PM | #1 |
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Over the last few weeks I've started noticing a somewhat subtle rattling (?) sound, which I believe may be coming from the transmission.
2011.5 e92 DCT ZCP I tried searching but couldn't find much of anything that pertains specifically to what I'm hearing. I can only describe the sound as how a junky old car's transmission rattling might sound when they apply acceleration. The sound is mostly only noticeable under relatively heavier loads (not flooring) around the 3-4k RPM in 3rd & 4th gears. I'll try to get some video soon! Anyone have any similar experiences? Fixes? I'm hoping it's something simple. **Updated with Video** Still hard to tell with the wind noise... |
10-09-2019, 07:40 PM | #2 |
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So this could be a ton of things, I would recommend posting a video. This could be exhaust shield smacking against the exhaust, could be driveshaft related....
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10-10-2019, 10:43 PM | #5 |
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insufficient clues, could be many things. to narrow it down, does it sound like a coiled spring rattle ? If so suspect dual mass flywheel, not the transmission. Happened to mine.
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10-22-2019, 06:14 PM | #7 |
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I get the same thing when running in "auto" mode, even in 4 or 5...I think it's a bit of pre-detonation, personally.
When I am shifting manually (and since I do not let it load up) I do not seem to have the same issue. -Mark in St. Louis |
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DrFerry6728.50 |
10-23-2019, 06:34 AM | #11 |
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Easy enough to test the detonation theory. Clear adaptations and add enough octane booster to increase octane to 95.
If the ionic knock sensing is working properly, you should not get pinging type light detonation. The system works through the plugs and coils rather than knock sensors bolted to the block. Coils don’t seem to be a failure item. How old are the plugs? Does a high level scan tool show any stored or pending faults? |
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10-23-2019, 09:48 AM | #12 | |
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I haven't done any "testing" per se...but...it only seems to occur when the revs are too low for the given speed (ie short shifting), brought on by the auto programming, in my case....generally below 3k. -Mark |
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DrFerry6728.50 |
10-23-2019, 05:18 PM | #13 | |
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DrFerry6728.50 |
10-23-2019, 05:19 PM | #14 | ||
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11-02-2019, 08:27 PM | #15 |
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A few quick updates - still looking for some help!
I took the car out with a friend the other day so we could try to narrow down what might be going on. - the sound doesn't seem to change whether the car is cold or full temp. - when revving to neutral, no rattling sound so doesn't seem exhaust related (maybe?) - you can hear a hint of it if you put your foot into it while in reverse - we jacked the car up but can't find anything loose or obvious. The mystery continues... |
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11-02-2019, 09:51 PM | #16 |
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It's probably worth taking a look at the driveshaft center mount / support bearing, part # 26122283046.
Video Example of Failing Center Mount |
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SoCalRPM885.50 |
11-14-2019, 10:45 PM | #17 |
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SoCalRPM I have the same issue and it certainly sounds like detonation. Also exactly what the OP experienced in this post: https://www.m3post.com/forums/showth...1532390&page=6
His solution was replacing the O2 sensors and new x-pipe. I have a pair of O2 sensors on order now hoping it would fix it for me too. |
11-16-2019, 10:16 AM | #18 | |
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I haven't found a solution yet but will report back when I do! |
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11-16-2019, 10:17 AM | #19 | |
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02-10-2020, 06:15 PM | #20 | |
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engine rattle
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i Have the exact same noise! I am running alpine stage 2 93 octane tune. I have not tried going back to stock yet. I read your replies in the pre-detonation thread. I hope its not that, i rather it be a noise csb. Have you researched this any further or ever figured out what the noise was? |
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02-10-2020, 09:11 PM | #21 | ||
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This is a recent discovery so I haven't contacted Alex directly yet. I may try removing the tune first to see if that removes the sound. |
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02-12-2020, 06:04 PM | #22 | |
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Drives: 2011 E92 M3
Join Date: Oct 2017
Location: Victoria
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Quote:
Also, if you can find someone with a "knock-box" type device, you can see if it is knock really quickly. And FYI, there is a handy place on the bottom of the block near the crank pully to mount the sensor - it is a bit of a pain because you have to take off the big skid plate but I could not find any other easy spot to install the sensor. As for the tune options, Alex gave me a "winter" tune that seems to be WAY better but still put down 382.7HP on the dyno. Hope this works our for you. Please let us know what the solution is. Cheers,
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