GT S faint knocking sound intermittent
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BMW M3 cabrio
Thanks for the continuing support
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BMW M3 cabrio
Probably fair to assume it's *exactly* as you surmised upthread (confusion.)
Utterly delicious!
I bought and had them put in new engine air-filters (no real reason,) and they changed oil and I was driving a GLC300 for the last week, SO, we all know how that goes-- felt so damn good to be back in there that I can't distinguish what's what other than "oh my god, I missed this thing!"
Will have to wait for a cold-start to know if the noise is gone, they said there was no trace of it this am. Regardless, whatever it was/is, it led to the discovery of this problem, which I'm pretty glad about.
Utterly delicious!
I bought and had them put in new engine air-filters (no real reason,) and they changed oil and I was driving a GLC300 for the last week, SO, we all know how that goes-- felt so damn good to be back in there that I can't distinguish what's what other than "oh my god, I missed this thing!"
Will have to wait for a cold-start to know if the noise is gone, they said there was no trace of it this am. Regardless, whatever it was/is, it led to the discovery of this problem, which I'm pretty glad about.
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BMW M3 cabrio
And, my bad, one clarification; there was a separate line-item on another page for repairs to cylinder 8, w/ injector replaced etc due to "cold start misfires"-- sorry about the bad info.
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From: Chicagoland
Schwinn
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BMW M3 cabrio
Got a slightly different version of the sound and car has a bit of a shake to it when parked and running. Doesn’t need to be cold anymore to manifest itself.
Last edited by JonDiamond; Aug 14, 2021 at 11:31 AM.
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From: Chicagoland
Schwinn
Something as simple as a loose clamp on intercooler tube will make the car run like crap. Man i feel for you, wish you were in my area as I would love to look at this thing and see what its doing.
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BMW M3 cabrio
I can't say I have an actual strategy here, but, for now, driving it around, ignoring it when it's present, and then will take it in to dealer after about a month to check and see if there are misfires again and/or maybe inspect the spark-plugs, etc. Feels like maybe the noise is a belt as suggested, at this point-- very unclear to me how that plays in with the misfires that were discovered (complete coincidence vs some other theory.) But, in any case, will be checking it frequently while not wanted to just have it spend whole week(s) at a time in the dealership vs. me sorta putting my head in the sand for now and driving (and enjoying the crap out of) it as I normally would.
Member
Joined: Sep 2017
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From: Chicagoland
Schwinn
I can't say I have an actual strategy here, but, for now, driving it around, ignoring it when it's present, and then will take it in to dealer after about a month to check and see if there are misfires again and/or maybe inspect the spark-plugs, etc. Feels like maybe the noise is a belt as suggested, at this point-- very unclear to me how that plays in with the misfires that were discovered (complete coincidence vs some other theory.) But, in any case, will be checking it frequently while not wanted to just have it spend whole week(s) at a time in the dealership vs. me sorta putting my head in the sand for now and driving (and enjoying the crap out of) it as I normally would.
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Joined: May 2021
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From: Utah
2018 Diamond White GT-R
Didn't you mention that in the beginning the car preformed well but you would hear the noises that bothered you? Its under warranty for awhile so drive it hard (NOT abuse) , if it is something major it will, as mentioned show itself. Have you talked to your MB dealer and told them the latest?
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BMW M3 cabrio
Took the car back in as I basically planned, plus the other day cold idle was a bit ugly and uneven.
They noted same and have replaced all the remaining injectors and all the plugs, will report back. Thanks as always!
They noted same and have replaced all the remaining injectors and all the plugs, will report back. Thanks as always!
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From: Chicagoland
Schwinn
Good luck.
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BMW M3 cabrio
Yes, absolutely, they did a cold start yesterday morning, that led them to put in the parts today, now keeping overnight for a cold start tomorrow morning , definitely not trusting anything shy of 12++ hours of sitting.
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BMW M3 cabrio
So I left the dealership on Friday without taking a copy of the paperwork, when I have a PDF of it, will post the actual work performed.
Mean time, I was told (again to be verified once I have the actual paperwork) that: all (remaining? (not sure)) plugs, coils and injectors were replaced.
I haven't driven it much since I picked it up, but, from the drive home and a few short drives since, I'd tentatively say the idle is -much- better at cold start and I think I'd say much better overall. There's a smoothness there that I guess I just didn't even realize had gone missing, I guess it degraded over time, then the knocking sound showed up, then the first repair didn't do all that much, and, now, it feels beautiful to me all of a sudden. Will continue to report back.
Speaking of smoothness and not realizing how "off" something was; the rear wing mechanism was replaced and is MUCH quieter, smoother and less obtrusive than it was/had become. I feel on that one, it was either a) never right from the day I received the car, or, b) degraded over time. It was quite chattery and kinda squeaky (or a "howl" almost) and it also was *constantly* re-latching itself (that's what it sounded like anyway,) when doing driving that didn't even remotely require the wing to deploy.
Mean time, I was told (again to be verified once I have the actual paperwork) that: all (remaining? (not sure)) plugs, coils and injectors were replaced.
I haven't driven it much since I picked it up, but, from the drive home and a few short drives since, I'd tentatively say the idle is -much- better at cold start and I think I'd say much better overall. There's a smoothness there that I guess I just didn't even realize had gone missing, I guess it degraded over time, then the knocking sound showed up, then the first repair didn't do all that much, and, now, it feels beautiful to me all of a sudden. Will continue to report back.
Speaking of smoothness and not realizing how "off" something was; the rear wing mechanism was replaced and is MUCH quieter, smoother and less obtrusive than it was/had become. I feel on that one, it was either a) never right from the day I received the car, or, b) degraded over time. It was quite chattery and kinda squeaky (or a "howl" almost) and it also was *constantly* re-latching itself (that's what it sounded like anyway,) when doing driving that didn't even remotely require the wing to deploy.
