N54 Acceleration mystery

ptack · 11-10-2015, 12:13 PM

So my 2008 135i has developed a strange issue. Under normal driving there are no problems, but if I floor it the engine goes into 1st gear, cars starts moving, revs to 4k and then stays there for about 2-3 seconds before finally catching and simultaneously surging to 7k and spinning the tires. No codes or odd sounds (i.e. turbo rattle). Suggestions?

lowbudgethero · 11-10-2015, 12:58 PM

manual or automatic?

Solo_M_Tech · 11-10-2015, 01:10 PM

Sounds like clutch slip (6MT) or the transmission friction discs (automatic) are worn out.

ptack · 11-10-2015, 02:00 PM

Sorry - automatic transmission.

BrokenVert · 11-10-2015, 02:10 PM

Sounds like a transmission issue. Could be a number of things, though.

When was the last time you flushed the fluid?

darkrom · 11-10-2015, 06:20 PM

Sounds like transmission to me too :/ Last time I had those symptoms were in a shitbox that needed a tranny rebuild. Hopefully its something simple, but its almost definitely the trans...

ptack · 11-11-2015, 09:46 AM

What's odd is there are no error codes though the engine seems to be holding itself back. If the engine was getting feedback from the transmission to limit the revs like that then you would think it would trigger a code.

Stvee · 11-11-2015, 10:05 AM

Does it do it in manual mode or only in Drive? Is it only in first gear?

It doesn't sound like the transmission is slipping. It wouldn't "catch" and spin the tires if it were. The revs would just shoot up and you wouldn't move faster accordingly.

ptack · 11-19-2015, 08:26 PM

Turns out it was injector mapping. Somehow at the last time I took it to the dealership they changed the codes and it mapped the injectors wrong. I suppose that's a good thing since fixing it did not entail a new clutch or transmission or turbos.

11-10-2015, 12:13 PM	#1
ptack Brigadier General 269 Rep 4,470 Posts Drives: 135i Join Date: May 2008 Location: NJ iTrader: (0) Garage List 2008 135i [6.50]	N54 Acceleration mystery So my 2008 135i has developed a strange issue. Under normal driving there are no problems, but if I floor it the engine goes into 1st gear, cars starts moving, revs to 4k and then stays there for about 2-3 seconds before finally catching and simultaneously surging to 7k and spinning the tires. No codes or odd sounds (i.e. turbo rattle). Suggestions? __________________ 135i, SGM, Coral, Sport Package, Auto, Premium Hifi, USB/ipod, Apex EC-7s, PPK Stage II
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11-10-2015, 12:58 PM	#2
lowbudgethero Captain 125 Rep 750 Posts Drives: '98 Z3M (gone), '09 135i Join Date: Feb 2013 Location: 908 iTrader: (0) Garage List 2009 BMW 135i [8.50]	manual or automatic?
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11-10-2015, 01:10 PM	#3
Solo_M_Tech Brigadier General 1688 Rep 3,140 Posts Drives: 2014 M5 6MT Join Date: Nov 2013 Location: Massachusetts iTrader: (7) Garage List 2014 BMW M5 [0.00]	Sounds like clutch slip (6MT) or the transmission friction discs (automatic) are worn out. __________________ 2014 M5 6MT
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11-10-2015, 02:00 PM	#4
ptack Brigadier General 269 Rep 4,470 Posts Drives: 135i Join Date: May 2008 Location: NJ iTrader: (0) Garage List 2008 135i [6.50]	Sorry - automatic transmission. __________________ 135i, SGM, Coral, Sport Package, Auto, Premium Hifi, USB/ipod, Apex EC-7s, PPK Stage II
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11-10-2015, 02:10 PM	#5
BrokenVert Resident Kerbalnaut 477 Rep 10,703 Posts Drives: Topless Brute/Hybrid Boogaloo Join Date: Apr 2009 Location: Fahrvergnügen/NY iTrader: (0)	Sounds like a transmission issue. Could be a number of things, though. When was the last time you flushed the fluid? __________________
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11-10-2015, 06:20 PM	#6
darkrom Colonel 188 Rep 2,224 Posts Drives: 135i Join Date: Feb 2011 Location: Rhode Island iTrader: (5)	Sounds like transmission to me too :/ Last time I had those symptoms were in a shitbox that needed a tranny rebuild. Hopefully its something simple, but its almost definitely the trans...
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11-11-2015, 09:46 AM	#7
ptack Brigadier General 269 Rep 4,470 Posts Drives: 135i Join Date: May 2008 Location: NJ iTrader: (0) Garage List 2008 135i [6.50]	What's odd is there are no error codes though the engine seems to be holding itself back. If the engine was getting feedback from the transmission to limit the revs like that then you would think it would trigger a code. __________________ 135i, SGM, Coral, Sport Package, Auto, Premium Hifi, USB/ipod, Apex EC-7s, PPK Stage II
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11-11-2015, 10:05 AM	#8
Stvee Private First Class 21 Rep 157 Posts Drives: 2010 BMW 135i Join Date: Apr 2014 Location: Harrisonburg, VA iTrader: (2)	Does it do it in manual mode or only in Drive? Is it only in first gear? It doesn't sound like the transmission is slipping. It wouldn't "catch" and spin the tires if it were. The revs would just shoot up and you wouldn't move faster accordingly.
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11-19-2015, 08:26 PM	#9
ptack Brigadier General 269 Rep 4,470 Posts Drives: 135i Join Date: May 2008 Location: NJ iTrader: (0) Garage List 2008 135i [6.50]	Turns out it was injector mapping. Somehow at the last time I took it to the dealership they changed the codes and it mapped the injectors wrong. I suppose that's a good thing since fixing it did not entail a new clutch or transmission or turbos. __________________ 135i, SGM, Coral, Sport Package, Auto, Premium Hifi, USB/ipod, Apex EC-7s, PPK Stage II
	Appreciate 0 Quote