X5M rough idle?

JVX6M · 04-13-2017, 05:30 PM

My 12' X5M has been in the dealership for two weeks for high battery drain and very rough idle sporadically. High battery drain was supposedly rear door handle issue and they cannot seem to diagnose the on and off rough idle after replacing an intake pressure sensor which they thought was the culprit. Any ideas or similar past experiences gents?

Revnato · 04-13-2017, 05:56 PM

I had bad some spark plugs that caused rough idling and misfires, could be that

BMW-SRT · 04-13-2017, 08:18 PM

Could be a leaky injector. If any of your plugs have a slight smell of gas then its deff a leaky injector.

Could also be carbon build up in your intake vavles, known issue with other BMW engines. Walnut blasting would be required.

m5james · 04-13-2017, 09:09 PM

The tell tale sign of bad injectors for me was black peppering all over the back of the truck, then ultimately it smoked like crazy when it finally gave up. Walnut blasting on these is a bitch due to intake manifold location.

TKR · 04-14-2017, 12:34 AM

I had a rough idle for over 2 months (actually running rough all the time but noticeable when idle), and dealer was not able to identify problem.

One of the very first steps in dealer diagnostics procedure is replacing Air mass Sensors as they are know to fail. They will also smoke test the intake system to find leaks, and visually inspect exhaust leaks. They couldn't find air leaks.

In my case they found one cylinder misfiring and swapped new injector (warranty). It did not solve running rough problem. At this point they requested 5hrs work authorisation for further investigation. That would have been $1k just for labor.

Swapped plugs and coils myself. Was still running rough.

Finally took the car to another dealer. They immediately diagnosed faulty Air mass sensor on Bank1. I paid the diagnostics §160 and swapped the Air mass sensor myself.

Has been running smooth since then.

m5james · 04-14-2017, 12:48 AM

The X5M S63 doesn't have MAF sensors vs the X5 N63 that does.

TKR · 04-14-2017, 11:46 AM

Oh sorry please ignore my comment about MAF's.

Anyway I would bet the rough idle is caused by wrong air/fuel mixture, which can be caused by unmetered air in combustion chambers or faulty injectors.

JX5M, Have the spark plugs ever been changed? What are the Injector index numbers? Did they change Bank 1 or 2 intake pressure sensor or both? Did the dealer find any fault codes?

04-13-2017, 05:30 PM	#1
JVX6M First Lieutenant 166 Rep 377 Posts Drives: 2023 BMW M3 Comp Join Date: Feb 2011 Location: Illinois iTrader: (0)	X5M rough idle? My 12' X5M has been in the dealership for two weeks for high battery drain and very rough idle sporadically. High battery drain was supposedly rear door handle issue and they cannot seem to diagnose the on and off rough idle after replacing an intake pressure sensor which they thought was the culprit. Any ideas or similar past experiences gents?
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04-13-2017, 05:56 PM	#2
Revnato Second Lieutenant 77 Rep 238 Posts Drives: 12' X5M Join Date: Jul 2016 Location: Los Angeles iTrader: (0)	I had bad some spark plugs that caused rough idling and misfires, could be that
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04-13-2017, 08:18 PM	#3
BMW-SRT First Lieutenant 170 Rep 347 Posts Drives: C63sAMG, GLC63sAMG, x5m, 335i Join Date: Jan 2011 Location: Cen-Cal iTrader: (0)	Could be a leaky injector. If any of your plugs have a slight smell of gas then its deff a leaky injector. Could also be carbon build up in your intake vavles, known issue with other BMW engines. Walnut blasting would be required. Last edited by BMW-SRT; 04-13-2017 at 08:45 PM..
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04-13-2017, 09:09 PM	#4
m5james Colonel 431 Rep 2,062 Posts Drives: '10 X5M Alpine White on Sakhir Join Date: Aug 2015 Location: Marysville, WA iTrader: (0)	The tell tale sign of bad injectors for me was black peppering all over the back of the truck, then ultimately it smoked like crazy when it finally gave up. Walnut blasting on these is a bitch due to intake manifold location.
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04-14-2017, 12:34 AM	#5
TKR Private First Class 26 Rep 119 Posts Drives: 2016 X5 40e & 2018 330e Join Date: Aug 2015 Location: South Florida iTrader: (0)	I had a rough idle for over 2 months (actually running rough all the time but noticeable when idle), and dealer was not able to identify problem. One of the very first steps in dealer diagnostics procedure is replacing Air mass Sensors as they are know to fail. They will also smoke test the intake system to find leaks, and visually inspect exhaust leaks. They couldn't find air leaks. In my case they found one cylinder misfiring and swapped new injector (warranty). It did not solve running rough problem. At this point they requested 5hrs work authorisation for further investigation. That would have been $1k just for labor. Swapped plugs and coils myself. Was still running rough. Finally took the car to another dealer. They immediately diagnosed faulty Air mass sensor on Bank1. I paid the diagnostics §160 and swapped the Air mass sensor myself. Has been running smooth since then.
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04-14-2017, 12:48 AM	#6
m5james Colonel 431 Rep 2,062 Posts Drives: '10 X5M Alpine White on Sakhir Join Date: Aug 2015 Location: Marysville, WA iTrader: (0)	The X5M S63 doesn't have MAF sensors vs the X5 N63 that does.
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04-14-2017, 11:46 AM	#7
TKR Private First Class 26 Rep 119 Posts Drives: 2016 X5 40e & 2018 330e Join Date: Aug 2015 Location: South Florida iTrader: (0)	Oh sorry please ignore my comment about MAF's. Anyway I would bet the rough idle is caused by wrong air/fuel mixture, which can be caused by unmetered air in combustion chambers or faulty injectors. JX5M, Have the spark plugs ever been changed? What are the Injector index numbers? Did they change Bank 1 or 2 intake pressure sensor or both? Did the dealer find any fault codes?
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