04-13-2017, 05:30 PM | #1 |
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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, 08:18 PM | #3 |
First Lieutenant
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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 |
Colonel
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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 |
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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, 11:46 AM | #7 |
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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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