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N55 Lean Issues
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02-11-2020, 02:15 PM | #1 |
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N55 Lean Issues
Hey guys,
This is my first post, so hopefully I have this in the right place. My 2011 335i w/ 88k miles (MHD Stage 1+, 91 tune running 92 octane) seems to be running lean. I had shadow codes related to the HPFP back in December in which I replaced it with a remanufactured from ECS Tuning along with the rail pressure sensor. Recently I've been getting lean codes 2BC0, 2C42, accompanied with infrequent stalling at a stop, idle fluctuation/surging (not large increments). I ran a smoke test and only found smoke seeping from the air intake hose that connects to the turbo inlet. I've ordered a replacement gasket for that connection. Spark plugs are under 5k being one-step colder. I dont know if coil packs or injectors were replaced before my ownership. MHD data logs for a few pulls below. https://datazap.me/u/versauce/log-1 https://datazap.me/u/versauce/log-2 Any help is greatly appreciated. |
02-11-2020, 08:15 PM | #2 |
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If you flash back to stock do your errors clear and stay cleared .. What I am getting at is the MHD might be the problem...
You do have a lot of correction on cylinder 2 I would look into.. Swapping coils and plug see if issue follows.. But your stalling and error from what I have seen points to MHD.. |
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02-12-2020, 07:57 AM | #3 |
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I noticed a couple of things when comparing to my Stage 1+ logs.
First off, your air to fuel ratio isn't really pointing towards a big lean state. I mean it is a bit on the high sides compared to the norms but it wouldn't be enough to tip us towards something. The long term fuel trim is at an average of -7.5 which is acceptable since it's under -10%, but it is suggesting that the PCM is correcting by leaning out the system because it's thinking it's too rich. This brings me to your MAF reading. On Stage 2+ and Stage 1+ for me, my MAF tappers around 285 g/s while yours stops at around 250 g/s. I don't know if this has a big or negligible impact on the fuel trims but it's just something I noted. Just a couple of things I noted, but that don't mean much. I would start maybe by doing simple stuff like resetting adaptations.
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TOTALED | 2011 E90 335i xDrive - BMS Cold Air Intake - ETS Charge Pipe - ETS 7" FMIC - MHD Stage 2+ - GFB DV+ - PE Mod - VRSF Catless Downpipe - xDelete - xHP Stage 3
2015 E84 X1 35i M-Sport |
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02-12-2020, 08:54 AM | #4 |
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The lean conditions that I seen where not under load.. It was under normal running before the pull started.. The pull itself didn't look bad for air fuel mixture.. What I have read it a know problem with the MHD and n55 platform.. Easy to see just flash back to stock..
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02-12-2020, 09:22 AM | #5 | |
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02-13-2020, 10:21 AM | #6 |
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So I tried flashing to stock, same issue persisted. I removed MHD completely, same thing. That then brought me to the MAF suggestion. I unplugged the MAF and drove the rest of the day with it disconnected. Off the bat I noticed the car ran much smoother. I did a log on my way home last night and it appears fuel trims look better? Along with less timing corrections.
I still have concerns about my boost but with the MAF off I was closer to where it should be. I still think I need a new boost solenoid. I did also install the turbo inlet gasket last night. https://datazap.me/u/versauce/log-15...og=0&data=3-12 |
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02-13-2020, 10:47 AM | #7 | |
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MAF is a parity check against speed density (TMAP vs throttle position).
By disconnecting it, you told the DME to pound sand when it comes to checking metered air vs speed density lookup. Additionally, you're maxing out STFT in your log (20%) - stop it. Listen to other people. Don't be a dummy. Thanks for skimping out on the log parameters. Your starting fuel pressure is a bit higher than what it should be - ~2930psi vs ~2750psi. It then tapers off to what it should be at 5000rpm (2450psi). You're still experiencing some pre-igniton, but it's not extreme, just stuff I would want to tune out. Cyl 5 is noisy, so its just -3 in a few places. I can't give any insight on this. You're experiencing a lean condition - period. I doubt it is a "vacuum leak" since this is underboost; you would be seeing a rich condition if there was a boost leak (with MAF). Without MAF, you're just getting incorrect fueling, period. What is your history on TMAP / MAF? any changes? Quote:
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02-14-2020, 03:17 PM | #8 | |
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OP, did you fix the intake piping? did you take a log at idle like requested? Last edited by bbnks2; 02-14-2020 at 03:23 PM.. |
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04-27-2020, 02:00 PM | #10 | |
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Replace the maf sensor ... |
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10-14-2023, 12:00 PM | #11 | |
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Drives: 335xi M Sport e92
Join Date: Nov 2022
Location: Waterford, MI
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Any updates? Also what codes were you getting exactly? Im getting these following codes- 2BCB 2D2F (Shadow) And 2D34 after replacing upstream o2 sensor. N55 with FBO, mhd stage 0 tune. |
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10-14-2023, 04:26 PM | #12 |
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The shadow code is normal for the downpipe. I have them too and MHD suppresses them.
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2007 E92 335i - MHD, Turbo Technics 19T's
2008 E60 535XI - JB4 2010 E92 335i - JB4, Borg Warner EFR 8374 |
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10-14-2023, 06:52 PM | #13 | |
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Drives: 335xi M Sport e92
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Here is a log: https://datazap.me/u/enayet/partial-...ta=11-14-15-19 Getting around 14.6 AFR at full throttle, and some timing corrections. Let me know your thoughts! Thanks! |
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10-17-2023, 01:16 PM | #14 | |
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2007 E92 335i - MHD, Turbo Technics 19T's
2008 E60 535XI - JB4 2010 E92 335i - JB4, Borg Warner EFR 8374 |
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10-17-2023, 01:18 PM | #15 | |
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2007 E92 335i - MHD, Turbo Technics 19T's
2008 E60 535XI - JB4 2010 E92 335i - JB4, Borg Warner EFR 8374 |
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10-17-2023, 01:24 PM | #16 | |
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2007 E92 335i - MHD, Turbo Technics 19T's
2008 E60 535XI - JB4 2010 E92 335i - JB4, Borg Warner EFR 8374 |
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10-17-2023, 01:26 PM | #17 | |
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2007 E92 335i - MHD, Turbo Technics 19T's
2008 E60 535XI - JB4 2010 E92 335i - JB4, Borg Warner EFR 8374 |
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10-19-2023, 10:26 AM | #18 |
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Drives: 335xi M Sport e92
Join Date: Nov 2022
Location: Waterford, MI
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Yes I am on stage 0 and running 93 octane.
I bought the car with a stage 0 tune and full bolt-on. -Catless downpipe -cold air intake -7.5 in intercooler The previous owner had it in MHD stage 2+ tune but set it to stage 0 when selling. I have driven about 10,000 miles since I bought it in stage 0. I recently purchased the MHD super license to monitor the car and tune it eventually. What do you think could be the reason behind the turbo overworking? I appreciate your response! |
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10-19-2023, 04:23 PM | #19 | |
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2007 E92 335i - MHD, Turbo Technics 19T's
2008 E60 535XI - JB4 2010 E92 335i - JB4, Borg Warner EFR 8374 |
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10-19-2023, 04:44 PM | #20 | |
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2007 E92 335i - MHD, Turbo Technics 19T's
2008 E60 535XI - JB4 2010 E92 335i - JB4, Borg Warner EFR 8374 |
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09-03-2024, 07:26 PM | #21 |
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I had the same codes but the leak was coming from one of the worst spots to be leaking... If you have these codes make sure the pressure isn't escaping the engine from the front main seal. I smoke tested the engine multiple times and didn't see any leaks, brought it for a diag at ACI Dynamix and they told me the bad news.
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09-10-2024, 03:21 AM | #22 | |
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Last week though I finally got another code to point me in the right direction of what it could be (having replaced all the intake o-rings which didn't solve it). 2CF4 - Oxygen Sensor before catalytic converter, dynamics: Slow response So I have ordered a new pre-cat O2 sensor and will attempt fitting this weekend. I have some logs here both of the idle itself (usually stalls when reversing & worse in the wet) and pulls and steady state, all with 2BC0 and occasionally combined in 2C42. https://datazap.me/u/lemansn55 |
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335i, bmw, e92, n55 |
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