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      04-02-2020, 10:03 PM   #1
thejeremyman9
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Help - Concerning Noise from Rear Seat / Center Consol Area

2015 335i RWD 8AT Msport. Fabspeed catted DP, VRSF IC+CP. Stock suspension, wheels, etc. MHD Stage 2+ 91 tune.

So, i started hearing a noise the other day. Conincidentally (may be a coincidence or not), it seemed to start shortly after i added 2 gallons of E85 and the rest 91 to a tank of gas. This is my first timing mixing in ethanol on this car.

I would best describe the sound as somewhat like grinding, but also like when a pump is sucking air. Some notes about the sound:

- It is definitely load/boost dependent. It is loudest when WOT, in any gear, and in boost.
- It is not really RPM dependent. I can accelerate up to 6k rpm at low throttle and the noise does not occur.
- Also not speed or gear dependent. It can occur if i floor it in any gear, whether its 1st gear at 5000 rpm or 5th gear and 2500 rpm.
- Started when i had a full tank of gas, still at half a tank and it sounds the same or maybe worse (could just be that i am more focused on it now). So i dont think its the fuel pump getting air.

It does sound like its around where the LPFP would be... and it did seem to start right after adding the E85, but it was only 2 gallons... I captured a log right when the noise started happening (i was checking for HPFP dips also), but of course i cant get any info on LPFP from that. https://datazap.me/u/thejeremyman9/4...ta=4-5-6-25-27

Interestingly my STFT are quite negative in most of that log, despite the ethanol on a non E tune.

Anyways, looking for any input on what it could be. Does it sound like LPFP?

I am still under CPO warranty for a little longer thankfully, and i was already planning to take the car in for some other stuff this month, so i am going to just go in for an oil change and brake fluid flush and have BMW check it out. I am not 100% sure if it will do it on stock tune, but i am going to completely uninstall MHD before taking it in anyways and will test that. I really hope it does so that it's repeatable for the dealer.

Here's a video, the sound actually sounds even louder here than in the car i think:


You can hear the noise a little when i first take off at medium throttle, it goes away when i let off, then get really loud when i step on it. This was 2nd gear i believe, but the gear doesnt make a difference.
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      04-03-2020, 08:58 AM   #2
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Get under your car and check this first. The clip retainer that holds the ebrake tube was hitting the driveshaft due to a broken part of this clip on mine. This happened to me when is was WOT or close to it and with with people in the back seat. some fatties loading me down, lol.

Here is that clip, https://www.ecstuning.com/b-genuine-...r/34406854898/

Its a pain in the ass to get to if you cant properly get under your car but easy to see from the back if you follow the drive shaft an it's right above the heat shield I believe.

Let me know what you find, Ill see if I can get a good pic for you.
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      04-03-2020, 09:30 AM   #3
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Quote:
Originally Posted by thejeremyman9 View Post
2015 335i RWD 8AT Msport. Fabspeed catted DP, VRSF IC+CP. Stock suspension, wheels, etc. MHD Stage 2+ 91 tune.

So, i started hearing a noise the other day. Conincidentally (may be a coincidence or not), it seemed to start shortly after i added 2 gallons of E85 and the rest 91 to a tank of gas. This is my first timing mixing in ethanol on this car.

I would best describe the sound as somewhat like grinding, but also like when a pump is sucking air. Some notes about the sound:

- It is definitely load/boost dependent. It is loudest when WOT, in any gear, and in boost.
- It is not really RPM dependent. I can accelerate up to 6k rpm at low throttle and the noise does not occur.
- Also not speed or gear dependent. It can occur if i floor it in any gear, whether its 1st gear at 5000 rpm or 5th gear and 2500 rpm.
- Started when i had a full tank of gas, still at half a tank and it sounds the same or maybe worse (could just be that i am more focused on it now). So i dont think its the fuel pump getting air.

It does sound like its around where the LPFP would be... and it did seem to start right after adding the E85, but it was only 2 gallons... I captured a log right when the noise started happening (i was checking for HPFP dips also), but of course i cant get any info on LPFP from that. https://datazap.me/u/thejeremyman9/4...ta=4-5-6-25-27

Interestingly my STFT are quite negative in most of that log, despite the ethanol on a non E tune.

Anyways, looking for any input on what it could be. Does it sound like LPFP?

I am still under CPO warranty for a little longer thankfully, and i was already planning to take the car in for some other stuff this month, so i am going to just go in for an oil change and brake fluid flush and have BMW check it out. I am not 100% sure if it will do it on stock tune, but i am going to completely uninstall MHD before taking it in anyways and will test that. I really hope it does so that it's repeatable for the dealer.

Here's a video, the sound actually sounds even louder here than in the car i think:


You can hear the noise a little when i first take off at medium throttle, it goes away when i let off, then get really loud when i step on it. This was 2nd gear i believe, but the gear doesnt make a difference.
Not sure if I would experiment with adding e85 with a non-ethanol tune. Since you may have a variable of increasing e85 for the first time and getting that noise, I would run the tank out and see if it returns with normal gas.
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      04-03-2020, 09:49 AM   #4
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Quote:
Originally Posted by 14F30Daily View Post
Get under your car and check this first. The clip retainer that holds the ebrake tube was hitting the driveshaft due to a broken part of this clip on mine. This happened to me when is was WOT or close to it and with with people in the back seat. some fatties loading me down, lol.

Here is that clip, https://www.ecstuning.com/b-genuine-...r/34406854898/

Its a pain in the ass to get to if you cant properly get under your car but easy to see from the back if you follow the drive shaft an it's right above the heat shield I believe.

Let me know what you find, Ill see if I can get a good pic for you.
+1

Check the ebrake tube because I has the same noise after installing the M-LSD but have heard that after time the tab on the ebrake cable breaks.
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      04-03-2020, 09:53 AM   #5
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Name:  retainer clip image.jpg
Views: 1581
Size:  235.6 KB this is a view of the tube and drive shaft
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      04-03-2020, 10:07 AM   #6
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Quote:
Originally Posted by jgoens View Post
Not sure if I would experiment with adding e85 with a non-ethanol tune. Since you may have a variable of increasing e85 for the first time and getting that noise, I would run the tank out and see if it returns with normal gas.
Tons of people do this; it is extremely common to add a few gallons of E85 on either 91 or 93 tunes to increase octane. I wouldn't have done it had i not researched extensively and taken logs after to verify fueling, etc. Thanks for the response though.

Quote:
Originally Posted by Munchi435i View Post
+1

Check the ebrake tube because I has the same noise after installing the M-LSD but have heard that after time the tab on the ebrake cable breaks.
Thanks both; I will try to get under the car today and see what i can find. Maybe the E85 was just a coincidence (kindof hoping and i want to be able to run it). My car only has 44k miles on it. Maybe the load is making the car squat and this contacts the driveshaft. Will report back.
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      04-03-2020, 11:18 AM   #7
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Quote:
Originally Posted by thejeremyman9 View Post
Tons of people do this; it is extremely common to add a few gallons of E85 on either 91 or 93 tunes to increase octane. I wouldn't have done it had i not researched extensively and taken logs after to verify fueling, etc. Thanks for the response though.



Thanks both; I will try to get under the car today and see what i can find. Maybe the E85 was just a coincidence (kindof hoping and i want to be able to run it). My car only has 44k miles on it. Maybe the load is making the car squat and this contacts the driveshaft. Will report back.
I have used e85 for many years, including with JB4, on this car and car before and have actually had a mix on non e85 maps, however, the gains were marginal at best in those cases. My point was more alluding to the mapping with MHD and how ethanol works with timing and boost may be different than just pure octane numbers. Though, I would figure 2 gal would not cause a noise like that.
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      04-03-2020, 11:54 AM   #8
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Quote:
Originally Posted by jgoens View Post
I have used e85 for many years, including with JB4, on this car and car before and have actually had a mix on non e85 maps, however, the gains were marginal at best in those cases. My point was more alluding to the mapping with MHD and how ethanol works with timing and boost may be different than just pure octane numbers. Though, I would figure 2 gal would not cause a noise like that.
The "gains" are basically preventing the "loss" associated with CA 91 octane not being good enough to run the 91 flash without having timing being pulled. My timing is really inconsistent, especially in winter. I can get logs with perfect timing on just pump 91; other times im getting like 5 degrees pulled on multiple cylinders. I am eventually going to try the E20 tune, i just tried a few gallons on the 91 tune to see how it cleaned up timing. I understanding how the maps will change boost and timing depending on expected ethanol content and/or octane of the map you select. Side discussion however to the noise it seems

Quote:
Originally Posted by Munchi435i View Post
+1

Check the ebrake tube because I has the same noise after installing the M-LSD but have heard that after time the tab on the ebrake cable breaks.

I think you guys win the prize. I wasn't able to full get under the car to check things with it on the ground but i captured a few pictures. It looks like there is a mark in the exact same location as the one 14F30Daily posted. Attachments are below.
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      04-03-2020, 01:51 PM   #9
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Hell yea man. That was my first post in this forum so glad I wasnt steering you in the wrong direction. Let me know how the fix goes but I believe you're going to need to drop the mid pipe, not fully remove it, and remove the heat shield, I dont think the drive shaft is mandatory. I have yet to fix mine properly cause Im not paying $700 for that $10 piece, I really just set a temp tie on the right ebrake tube until I can this done, gotta love BMW and their hidden plastic pieces...

There should be some posts in the past talking about how to fix this part specifically.

Good luck.
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      04-03-2020, 05:33 PM   #10
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Quote:
Originally Posted by 14F30Daily View Post
Hell yea man. That was my first post in this forum so glad I wasnt steering you in the wrong direction. Let me know how the fix goes but I believe you're going to need to drop the mid pipe, not fully remove it, and remove the heat shield, I dont think the drive shaft is mandatory. I have yet to fix mine properly cause Im not paying $700 for that $10 piece, I really just set a temp tie on the right ebrake tube until I can this done, gotta love BMW and their hidden plastic pieces...

There should be some posts in the past talking about how to fix this part specifically.

Good luck.
Did you get that $700 estimate from BMW? I just called and made an appointment for tomorrow for my oil change and brake fluid flush. I described the problem and he said it might be covered under CPO, depending on if "any external factor" caused it. I am removing my tune but obviously not taking off my IC/CP/DP before going it, so we will see what they say. It would be ridiculous if they rejected it for those mods honestly. If they refuse to cover under warranty i will probably just ziptie mine as well. I have some stainless steel zipties that should work.

I took a closer look at my photos and i think i actually see the broken clip now; the first time i just saw the mark on the driveshaft. So i am pretty confident this is what it is.
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      04-06-2020, 09:48 PM   #11
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So, to wrap this up, it was exactly what we thought it was. I took the car to the dealer and dropped it off on saturday for my oil chane, brake fluid flush, and this issue. I had to pay a $50 deductable for the CPO warranty claim but they covered it. The price quoted for the repair had it not been covered was over $900.

Annoyingly, they had to drop the gas tank to do it... not sure why as that didnt seem like the easiest approach. I just hope that did that correctly and i dont have any future issues with the tank, filler, rattles, etc. They also drained my gas as a part of that but i think they refilled with the same fuel? Not sure though so i am going to run this tank down as empty as i can before i mix some ethanol in my next tank.

I havent looked under the car yet since it was raining but next time i do ill try and grab some photos and post if anything is noteworthy.
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      04-07-2020, 07:28 AM   #12
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Good to hear, I'm out of CPO so this is going to be me doing it. Like how are they able to quote 900, seems I estimated even low. 890 in labor, comeon man. Dropping the gas tank to get there would seem like a complete waste of time but maybe makes the part install as easy as possible...
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      07-13-2020, 07:17 PM   #13
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Does anyone have a tutorial of how to replace this?
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      07-13-2020, 08:24 PM   #14
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Quote:
Originally Posted by bmrguy03 View Post
Does anyone have a tutorial of how to replace this?
Just reach under there a put a zip tie on it. The dealer dropped my tank as part of the warranty replacement and now i have the slow fuel fill issue described in this thread: https://f30.bimmerpost.com/forums/sh....php?t=1736419
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      09-14-2021, 12:39 PM   #15
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So I have the same sound in my ‘16F31 except it happens under load and when turning right only. I’m fine with a zip tie fix, do I need to drop any pans or splash guards to access this spot? Is it easier to get by jacking up the front or back?
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      09-14-2021, 01:26 PM   #16
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Originally Posted by Warrior9504 View Post
So I have the same sound in my ‘16F31 except it happens under load and when turning right only. I’m fine with a zip tie fix, do I need to drop any pans or splash guards to access this spot? Is it easier to get by jacking up the front or back?
Depends how small your hands are... you should be able to get to it without removing anything and you may just be able to crawl under the car. Just go look under your car while its park and confirm as shown in my photo above.
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      10-16-2021, 12:52 PM   #17
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Just to close the loop here. This was exactly the problem in my 2016 F31. The bracket wasn’t holding the two ebrake housing tubes and on turns those tubes would rub on the drive shaft. I managed to thread a zip tie behind the bracket and the two tubes and it seems to have worked. To replace the bracket you’d need to drop the exhaust and/or the drive shaft which sounds like a big PITA. I’ll try and post a pic when I’m at my computer next
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      10-16-2021, 01:29 PM   #18
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I have the same grinding noise when accelerating and turning right. Haven’t looked underneath the car yet, but seems likely that I have the same issue.
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      10-17-2021, 01:11 PM   #19
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Quote:
Originally Posted by Warrior9504 View Post
Just to close the loop here. This was exactly the problem in my 2016 F31. The bracket wasn’t holding the two ebrake housing tubes and on turns those tubes would rub on the drive shaft. I managed to thread a zip tie behind the bracket and the two tubes and it seems to have worked. To replace the bracket you’d need to drop the exhaust and/or the drive shaft which sounds like a big PITA. I’ll try and post a pic when I’m at my computer next
I had mine replaced under warrnaty and they dropped gas tank for it. Not sure what else they removed, but its a lot of work if you following the "book" procedure.
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      10-17-2021, 05:25 PM   #20
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OK. So here are two photos that hopefully help. I took the car for a longer drive today and can confirm this solved my noise problem. First photo you can clearly see where the ebrake tube is rubbing on the drive shaft and even the broken clip. In the second, you can (hopefully) see how I ran a zip-tie behind the broken clip and around the two ebrake tubes to hold them up and off the drive shaft. Took some work as the space is tight but my car is out of warranty and if this works I'll take a 1 hour (took me longer to put the car on and off the jack stands) work and $0.05 zip tie solution than another BMW clip that will probably just break anyway and the hours to drop all that stuff. As a tip, I did remove a few nuts holding the heat shielding in place to make it easier it access - just a 10mm socket there.
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      10-18-2021, 07:08 AM   #21
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      04-08-2023, 07:41 AM   #22
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I have the same sound on my 2015 328i. I thought it might be my wastegate, but now I'm going to have to check on this. Thanks for this post!
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