RPM fluctuations

hank1170 · 03-09-2017, 09:30 AM

I currently own a 2013 M5 with 38,000 kms. The check engine light came on and started stalling at red lights. I took it to BMW service numerous times and they said that the intake was contaminated with oil and thats why the check engine light kept coming on. No explaination of why it was stalling. I took it back a few times and they said that my the compression on one bank was lower than the other. They still couldnt figure it out. They ended up replacing the engine which I thought would definately solve the problem.

It has been 2,800kms since engine replacement. When I have the car in N and rev the engine up to 3,500-4,000 rpms, and let go of the gas pedal, the RPMs go down to 500rpms and then back to idle rpm of 700-800.

THis was happening with the old engine. I am afraid that the problem was not the engine itself. COuld it be one of the turbo is bad? My warranty has now expired, but would like this fixed. BMW service is telling me since there nothing is coming up on the computer so it's normal??? I have 2 friends with the same M5 and neither M5's do this. ANy help would be much appreciated.

SapphireM5 · 03-11-2017, 05:39 AM

Try cleaning your maf sensors. They could have oil on them from previous oil contamination.

13M5F10 · 03-11-2017, 08:48 AM

Definitely sounds like the MAF sensors are contaminated.

Pick up CRC Mass Air Flow Cleaner and follow the instructions. I would do it twice.

Hope that works.

hank1170 · 03-12-2017, 04:55 AM

Have had BMW do that twice already and it was spotless.

MpowerMike · 03-13-2017, 01:40 AM

Check your coils/plugs and o2 sensors.

hank1170 · 03-16-2017, 01:06 AM

Quote:

Originally Posted by MpowerMike

Check your coils/plugs and o2 sensors.

Thank you for all the comments. will the computer not give a warning if any of these sensors are bad or not working properly? BMW Korea has been the least helpful since warranty has expired.

tcrock08 · 07-24-2019, 10:35 AM

hank1170 hi - just curious if problem surfaced again or if BMW Korea eventually figured it out?

My 2014 m5 has occasional engine stalls at start up / start stop and idling a little rough. No codes or check engine light. BMW HK tried replacing spark plugs and MAF sensors to no effect. So curious if you have an update on your car...

03-09-2017, 09:30 AM	#1
hank1170 Registered 1 Rep 4 Posts Drives: 2013 F10 M5 Join Date: Feb 2017 Location: Korea iTrader: (0)	RPM fluctuations I currently own a 2013 M5 with 38,000 kms. The check engine light came on and started stalling at red lights. I took it to BMW service numerous times and they said that the intake was contaminated with oil and thats why the check engine light kept coming on. No explaination of why it was stalling. I took it back a few times and they said that my the compression on one bank was lower than the other. They still couldnt figure it out. They ended up replacing the engine which I thought would definately solve the problem. It has been 2,800kms since engine replacement. When I have the car in N and rev the engine up to 3,500-4,000 rpms, and let go of the gas pedal, the RPMs go down to 500rpms and then back to idle rpm of 700-800. THis was happening with the old engine. I am afraid that the problem was not the engine itself. COuld it be one of the turbo is bad? My warranty has now expired, but would like this fixed. BMW service is telling me since there nothing is coming up on the computer so it's normal??? I have 2 friends with the same M5 and neither M5's do this. ANy help would be much appreciated.
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03-11-2017, 05:39 AM	#2
SapphireM5 Major 711 Rep 1,107 Posts Drives: 2013 M5 Sapphire Black Join Date: Feb 2017 Location: New Jersey iTrader: (3)	Try cleaning your maf sensors. They could have oil on them from previous oil contamination. __________________ '13 Black Sapphire Metallic - BPM Stage 1 Tune - RPI Exhaust - KW HAS Kit - 12mm spacers all around- Carbon Fiber front lip - High Kick Trunk Spoiler - Rear Roof Spoiler - IND Kidney and Fender Grills - 20% Tint all around 50% Front Windshield - PPF
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03-11-2017, 08:48 AM	#3
13M5F10 Hide! My wife's coming! 812 Rep 2,816 Posts Drives: 2013 BMW M5 \| MSR Stage 3 Join Date: Jun 2015 Location: Las Colinas, TX iTrader: (5)	Definitely sounds like the MAF sensors are contaminated. Pick up CRC Mass Air Flow Cleaner and follow the instructions. I would do it twice. Hope that works. __________________ * SOLD * 2013 BMW M5 \| Space Grey \| MSR Stage 3 Tune \| Catless Downpipes \| MSR Intake and Charge Pipes \| MSR Exhaust (Prototype) \| Vorsteiner Rear Diffuser \| RW Carbon Front Lip \| RW Carbon Trunk Spoiler\| Vorsteiner VS-310 Forged Wheels \| Escort 9500CI w/Laser Jammers
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03-12-2017, 04:55 AM	#4
hank1170 Registered 1 Rep 4 Posts Drives: 2013 F10 M5 Join Date: Feb 2017 Location: Korea iTrader: (0)	Have had BMW do that twice already and it was spotless.
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03-13-2017, 01:40 AM	#5
MpowerMike Major 360 Rep 1,123 Posts Drives: 2012 IB BMW M5 Join Date: May 2014 Location: T.O. Canada iTrader: (1)	Check your coils/plugs and o2 sensors.
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07-24-2019, 10:35 AM	#7
tcrock08 New Member 14 Rep 9 Posts Drives: 2014 M5, 2010 335i Coupe Join Date: Apr 2011 Location: Hong Kong iTrader: (0)	hank1170 hi - just curious if problem surfaced again or if BMW Korea eventually figured it out? My 2014 m5 has occasional engine stalls at start up / start stop and idling a little rough. No codes or check engine light. BMW HK tried replacing spark plugs and MAF sensors to no effect. So curious if you have an update on your car...
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