N55 Software Update

rborane · 08-20-2018, 05:15 PM

My 2011 335 N55 is having random cold start surging issues where the idle will surge for a bit and rev on its own, and then eventually settle down to normal idle. I've read this is a common issue with 2011 N55's and that a software update from BMW is the fix.

If I flash the ECU with MHD, do I still need to update it through BMW, or does it essentially do the same thing and get rid of the surging issue?

Turbod · 08-20-2018, 05:40 PM

Unless MHD has changed from the original release they would be flashing your car to an older ROM. Could it fix the issue? Maybe. My guess is a dirty MAF or a MAF that isn't sealed correctly. Are you running the stock intake?

E92n55slo · 08-20-2018, 06:19 PM

Quote:

Originally Posted by rborane

My 2011 335 N55 is having random cold start surging issues where the idle will surge for a bit and rev on its own, and then eventually settle down to normal idle. I've read this is a common issue with 2011 N55's and that a software update from BMW is the fix.

If I flash the ECU with MHD, do I still need to update it through BMW, or does it essentially do the same thing and get rid of the surging issue?

Mhd has an option cold cold start reduction or something like that, fixes the issues

BourneJack · 08-20-2018, 06:22 PM

Quote:

Originally Posted by Turbod

Unless MHD has changed from the original release they would be flashing your car to an older ROM. Could it fix the issue? Maybe. My guess is a dirty MAF or a MAF that isn't sealed correctly. Are you running the stock intake?

+1

rborane · 08-20-2018, 07:11 PM

Quote:

Originally Posted by Turbod

Unless MHD has changed from the original release they would be flashing your car to an older ROM. Could it fix the issue? Maybe. My guess is a dirty MAF or a MAF that isn't sealed correctly. Are you running the stock intake?

Yes stock intake. This is the service bulletin I found. Maybe worth going to the dealer and presenting this?

I guess what im asking is even if BMW updates the DME, and then I flash MHD, does that overwrite the BMW update? Or will there be an updated DME still?

https://www.scribd.com/document/1519...T-Stalling-TSB

Turbod · 08-20-2018, 10:15 PM

Quote:

Originally Posted by rborane

Yes stock intake. This is the service bulletin I found. Maybe worth going to the dealer and presenting this?

I guess what im asking is even if BMW updates the DME, and then I flash MHD, does that overwrite the BMW update? Or will there be an updated DME still?

https://www.scribd.com/document/1519...T-Stalling-TSB

MHD flashes an older ROM. If you pay BMW to flash one it will flash back once you install MHD.

maddmatth · 08-21-2018, 12:19 AM

I have a DCT and I do not have this issue with the MHD ROMs, both with and without cold start noise reduction. It's probably based on a ROM that already has this fix, considering that TSB is from 2013, long before MHD was released for N55.

LiquidREVUP · 08-21-2018, 07:13 PM

Try cleaning MAF first

https://www.e90post.com/forums/showt...46#post8937746

08-20-2018, 05:15 PM	#1
rborane Captain 241 Rep 792 Posts Drives: BMW M4 Join Date: Mar 2013 Location: AZ iTrader: (3)	N55 Software Update My 2011 335 N55 is having random cold start surging issues where the idle will surge for a bit and rev on its own, and then eventually settle down to normal idle. I've read this is a common issue with 2011 N55's and that a software update from BMW is the fix. If I flash the ECU with MHD, do I still need to update it through BMW, or does it essentially do the same thing and get rid of the surging issue?
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08-20-2018, 05:40 PM	#2
Turbod Major 396 Rep 1,210 Posts Drives: 2014 E84 X1 35i M Sport Join Date: Mar 2015 Location: Oregon iTrader: (0)	Unless MHD has changed from the original release they would be flashing your car to an older ROM. Could it fix the issue? Maybe. My guess is a dirty MAF or a MAF that isn't sealed correctly. Are you running the stock intake? __________________ 2011 E92 335i \| 11.7@125 SOLD 2017 Camaro SS \| 12.7@114 SOLD 2019 Audi TT RS \| 10.5@130 SOLD 2020 F97 X3M \| 11.0@123 2023 G80 M3 xDrive
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08-21-2018, 12:19 AM	#7
maddmatth Major 555 Rep 922 Posts Drives: F82 M4, E92 335i Join Date: Jun 2015 Location: New Zealand iTrader: (0)	I have a DCT and I do not have this issue with the MHD ROMs, both with and without cold start noise reduction. It's probably based on a ROM that already has this fix, considering that TSB is from 2013, long before MHD was released for N55.
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08-21-2018, 07:13 PM	#8
LiquidREVUP Private 15 Rep 31 Posts Drives: 2011 335i E90 N55 6AT Join Date: Jul 2018 Location: Los Angeles iTrader: (0)	Try cleaning MAF first https://www.e90post.com/forums/showt...46#post8937746 __________________ Daily E90 N55 6AT: VRSF 7’’ HD core FMIC \| VRSF 2.5’’ Lower CP \| VRSF 3’’ Upper CP \| VRSF 3.5’’ Catless DP \| BMS OCC \| BMS Sport OCV \| N20 TMAP \| MHD E30 v1.51 beta \| xHP Stage 3 v2.0 \| 19” 351m wheels \| M Sport springs \| Bilstein B8 \| IG: @liquidrevup
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