07-31-2021, 12:50 PM | #1 |
Private First Class
168
Rep 160
Posts
Drives: 17 M2, 23 Ford F150 Raptor
Join Date: Jan 2017
Location: Los Angeles, CA and Phoenix, AZ
|
Hi guys, recently my M2 has really rough cold starts where the engine starts off sluggish, and RPMs dip below 500 RPM where the car sounds like it is about to die before going back up.
This happens only during cold starts and the car starts up no problem after that during the day. Any info what is the problem? Car is stock with just under 30,000 miles.
__________________
Current: 2017 Alpine White M2 DCT, 2023 Ford F-150 Raptor
Past: 2015 Lexus IS 250, 2014 Volkswagen CC R-Line |
08-15-2021, 02:42 AM | #2 |
Yoda of mods
1668
Rep 3,003
Posts
Drives: X5 RWD
Join Date: Feb 2018
Location: NC
|
Might be time for new spark plugs.
__________________
Current: 2020 Explorer ST (Agate Black Metallic), F15 SGM RWD
F87 AW (retired) F30 SBM 316rwhp/440rwtq (retired) Follow me on Twitter: https://twitter.com/EdwyerCLT YT: https://www.youtube.com/@DWYERGARAGE/videos |
Appreciate
0
|
08-15-2021, 01:47 PM | #3 |
Major
1167
Rep 1,227
Posts
Drives: 2017 Big Turbo BMW M2
Join Date: May 2021
Location: Tampa, FL
|
spark plugs or waste gate being loose possibly
|
Appreciate
0
|
08-16-2021, 11:42 AM | #4 |
Major General
5491
Rep 5,339
Posts |
With a fully warmed engine and the car in neutral, disconnect the MAF sensor and let it run a few minutes. Shut the car off and reconnect the MAF sensor. On the next cold start, the issue should likely be fixed.
|
10-24-2021, 11:35 PM | #5 |
Private First Class
168
Rep 160
Posts
Drives: 17 M2, 23 Ford F150 Raptor
Join Date: Jan 2017
Location: Los Angeles, CA and Phoenix, AZ
|
Thank you so much! A few weeks ago, my car stalled trying to do a cold start so I tried your method and now my car starts up no problem now. *Knock on wood*
__________________
Current: 2017 Alpine White M2 DCT, 2023 Ford F-150 Raptor
Past: 2015 Lexus IS 250, 2014 Volkswagen CC R-Line |
Appreciate
0
|
09-11-2022, 06:23 PM | #6 | |
Enlisted Member
11
Rep 32
Posts |
Quote:
|
|
Appreciate
0
|
09-15-2022, 10:20 PM | #7 | |
Private First Class
62
Rep 132
Posts
Drives: OG M2
Join Date: Jan 2019
Location: San Francisco, CA
|
Quote:
__________________
M2 - TC Kline DA Coilovers - Apex SM-10s - 265 RS-4s - Dinan Intake - BM3 - CSF Intercooler - VRSF CP
Previous: 6th Gen Camaro SS 1LE | 2020 JLUR Wrangler | F30 340i | B7 Audi A4 APR Tuned | E46 330ci Instagram @track.n.trail |
|
Appreciate
0
|
09-16-2022, 05:24 AM | #8 |
Lieutenant Colonel
332
Rep 1,581
Posts |
I've seen the same thing on my car a number of times, interestingly it started last May/June, persisted through the summer then Fall/Winter it went away, came back this May/June. My spark plugs were changed last year as well.
I'd be curious if anyone else has a slight ticking noise from the fuel tank breather line and the two things are related. |
Appreciate
0
|
09-16-2022, 08:55 PM | #9 |
Enlisted Member
11
Rep 32
Posts |
|
Appreciate
0
|
09-17-2022, 12:41 AM | #10 |
Captain
720
Rep 929
Posts
Drives: 2019 F87 M2C, 2023 G87 M2
Join Date: Mar 2018
Location: North America
|
|
Appreciate
0
|
09-17-2022, 10:45 AM | #11 |
Enlisted Member
11
Rep 32
Posts |
No, that's probably a good idea. I have had the car in for service several times for routine maintenance at Winslow BMW and I assumed they would scan for codes, but maybe they don't unless the CEL is on.
I just keep reading about this issue on the M235i forums and other N55 applications where nobody seems to have errant codes, and some of them never get it "fixed". Some think it's an error in the cold start tables that just builds up over time or something...who knows. I'm bringing my car in for an oil change to my independent BMW tech who has done good work for me in the past...I will have him chase this a little and see where it goes... |
Appreciate
0
|
09-17-2022, 11:10 AM | #12 |
Brigadier General
2785
Rep 3,681
Posts |
Pretty sure all these recent idle complaints are due to injectors getting older/used and either getting clogged up or beginning to leak.
Mine is in the shop for something similar and two plugs were black. Ran perfectly fine under load and at WOT, just a bad idle that got worse and worse over the last year. Kind of indicates leaking injectors in those cylinders, leading to rich mixture misfires at idle. Doing new injectors early this week & will let you all know. |
Appreciate
0
|
09-17-2022, 11:16 AM | #13 | |
Enlisted Member
11
Rep 32
Posts |
Quote:
|
|
Appreciate
0
|
09-17-2022, 11:28 AM | #14 | |
Brigadier General
2785
Rep 3,681
Posts |
Quote:
|
|
Appreciate
0
|
09-17-2022, 01:48 PM | #15 |
Enlisted Member
11
Rep 32
Posts |
|
Appreciate
0
|
09-17-2022, 02:52 PM | #16 | |
Enlisted Member
11
Rep 32
Posts |
Quote:
|
|
Appreciate
0
|
09-17-2022, 02:59 PM | #17 | |
Brigadier General
2785
Rep 3,681
Posts |
Quote:
|
|
Appreciate
0
|
09-17-2022, 03:01 PM | #18 |
Enlisted Member
11
Rep 32
Posts |
|
Appreciate
0
|
09-23-2022, 12:37 PM | #19 | |
Enlisted Member
11
Rep 32
Posts |
Quote:
|
|
Appreciate
0
|
09-23-2022, 01:30 PM | #20 | |
Brigadier General
2785
Rep 3,681
Posts |
Quote:
Plugs 3 & 6 were black, but the car ran fine with no misfires under WOT, so kind of points to an injector issue that was fouling those plugs and causing rough idle. That said, we went back with all new plugs & coils while we were in there (free FCP replacement items), and the injectors, and all is good. |
|
Appreciate
0
|
09-23-2022, 01:35 PM | #21 | |
Enlisted Member
11
Rep 32
Posts |
Quote:
|
|
Appreciate
0
|
09-23-2022, 01:45 PM | #22 | |
Brigadier General
2785
Rep 3,681
Posts |
Quote:
Anytime I've played the which plug, coil, (and now injector) to replace game, the labor ends up being more if you don't get it right the first time. And, my car has 40k miles, lots of track days, and years of running ethanol (also installed Bend's fuel filter), so probably better just to replace them all anyways. Maybe a little more painful the first-time cost wise to do them all at once, but now that I'm in the FCP replacement cycle for those parts, we just replace them all each time to completely rule out plug, coil, and now injector issues. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
Thread Tools | Search this Thread |
|
|