Anyone have RPM Fluctuation on Start?

derriktr · 10-22-2015, 08:42 PM

Every once in a while when I start the X3 up she immediately has RPM fluctuations. I'm not talking about regular one to two hundred RPM fluctuations, but audible and visual jumps on the tachometer. Anyone else experiencing this? This is occurring pre and post aftermarket battery reduction measures.

FSociety · 10-22-2015, 09:42 PM

Quote:

Originally Posted by derriktr

Every once in a while when I start the X3 up she immediately has RPM fluctuations. I'm not talking about regular one to two hundred RPM fluctuations, but audible and visual jumps on the tachometer. Anyone else experiencing this? This is occurring pre and post aftermarket battery reduction measures.

I actually just started noticing this yesterday and today and mostly when i'm slowing down or off the pedal, but not when starting up.

02420X3 · 10-22-2015, 11:11 PM

I've sometimes seen that on startup in winter weather, but not at any other time.

derriktr · 10-23-2015, 05:16 AM

I'll try and get a video of it. It's odd as it'll happen on cold starts and even when the engine is warm.

FSociety · 10-28-2015, 05:38 PM

Quote:

Originally Posted by derriktr

I'll try and get a video of it. It's odd as it'll happen on cold starts and even when the engine is warm.

Yes pls try

epiphone3 · 11-10-2015, 01:48 PM

I recently had been having fluctuations when slowing down and coming to a stop at traffic lights. Weird. When I changed fuels, it seemed to go away for the most part... when it was doing it a lot, I had a fuel that could have up to 10% methanol. The fuel after was just premium that doesn't state it could have the methanol.

Not sure where its coming from.

02420X3 · 11-10-2015, 07:06 PM

All fuel sold in my state has 10% methanol. I buy Top Tier 93 octane as a general rule. I've never had the problem that you describe. I don't believe that it is related to methanol in your fuel.

exon · 11-11-2015, 10:46 AM

i have this on cold start. goes away very quickly after startup though.

Sabean · 01-25-2024, 09:03 AM

I also have the same issue with My x3 Only does it on a cold start in the winter time. After it runs for about 10 minutes it’ll go back to perfect and it never throws the code. It’s got a new battery in it it did it and it did before the new battery installed mass sensor air filter. The oil filter doesn’t have any leaks on the cap. I’m at a loss I need to know what to look for.

slowblackx3f25 · 01-26-2024, 03:27 PM

Quote:

Originally Posted by derriktr

Every once in a while when I start the X3 up she immediately has RPM fluctuations. I'm not talking about regular one to two hundred RPM fluctuations, but audible and visual jumps on the tachometer. Anyone else experiencing this? This is occurring pre and post aftermarket battery reduction measures.

this is an old thread, I had this happen to me as well... usually when idling at a red light. It went away after I got the TCU tuned/updated with latest BMW trans software at this indy shop in Ontario, Canada.

I drive 6speed vehicles so I keep my eye and ear on the RPM needle.

slowblackx3f25 · 01-26-2024, 03:29 PM

Quote:

Originally Posted by exon

i have this on cold start. goes away very quickly after startup though.

during cold start, it's normal to see the RPM's rev high and stay there... it shouldn't fluctuate... it should be steady revving at 1,100rpm or whatever it's at during cold starts.

After the RPM needle should settle and hang around 900-800rpm...

chris55552 · 01-30-2024, 04:45 AM

I have a brand new replacement n55 with less than 5k miles on it in my 2017 and it starts up and fluctuates briefly and sounds pretty loud and gnarly, but within 20 to 30 seconds calms down and sounds more civilized. If yours is fluctuating beyond that I would look at the Mass air flow sensor, cleaning it or replacing it and I think the vanos solenoids could be to be blame. Def check the air filter, mass air flow sensor, and MAP sensor.

Houranimd49 · 02-07-2024, 09:44 AM

Over the last several N55s I’ve had, they all did this. It wasn’t always, but they did do this every one in a while. They can be moody motors. But it was nothing ever concerning to me because they all ran just fine and even then the fluctuations were minimal, <+/-100rpm, nothing crazy. Based on my experience, I wouldn’t worry about it.

slowblackx3f25 · 02-08-2024, 08:40 AM

Quote:

Originally Posted by Houranimd49

Over the last several N55s I’ve had, they all did this. It wasn’t always, but they did do this every one in a while. They can be moody motors. But it was nothing ever concerning to me because they all ran just fine and even then the fluctuations were minimal, <+/-100rpm, nothing crazy. Based on my experience, I wouldn’t worry about it.

I was told if it doesn't throw codes (CEL), don't worry about it.

It hasn't happened in a while (N20), it stopped after I updated the transmission software.

Houranimd49 · 02-08-2024, 10:03 AM

Quote:

Originally Posted by slowblackx3f25

I was told if it doesn't throw codes (CEL), don't worry about it.

It hasn't happened in a while (N20), it stopped after I updated the transmission software.

Exactly lol

10-22-2015, 08:42 PM	#1
derriktr New Member 6 Rep 20 Posts Drives: 2011 X3 35i XDrive Join Date: Oct 2015 Location: Pennsylvania iTrader: (0) Garage List 2011 BMW X3 35i XDrive [0.00]	Anyone have RPM Fluctuation on Start? Every once in a while when I start the X3 up she immediately has RPM fluctuations. I'm not talking about regular one to two hundred RPM fluctuations, but audible and visual jumps on the tachometer. Anyone else experiencing this? This is occurring pre and post aftermarket battery reduction measures. __________________ 2011 X3 35i XDrive
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10-22-2015, 11:11 PM	#3
02420X3 Captain 63 Rep 983 Posts Drives: 2011 X3 35i Join Date: Jun 2011 Location: Boston iTrader: (0)	I've sometimes seen that on startup in winter weather, but not at any other time.
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10-23-2015, 05:16 AM	#4
derriktr New Member 6 Rep 20 Posts Drives: 2011 X3 35i XDrive Join Date: Oct 2015 Location: Pennsylvania iTrader: (0) Garage List 2011 BMW X3 35i XDrive [0.00]	I'll try and get a video of it. It's odd as it'll happen on cold starts and even when the engine is warm. __________________ 2011 X3 35i XDrive
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11-10-2015, 01:48 PM	#6
epiphone3 Lieutenant Colonel 111 Rep 1,772 Posts Drives: 2013 BMW X3 35i Join Date: Oct 2005 Location: Calgary iTrader: (0)	I recently had been having fluctuations when slowing down and coming to a stop at traffic lights. Weird. When I changed fuels, it seemed to go away for the most part... when it was doing it a lot, I had a fuel that could have up to 10% methanol. The fuel after was just premium that doesn't state it could have the methanol. Not sure where its coming from.
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11-10-2015, 07:06 PM	#7
02420X3 Captain 63 Rep 983 Posts Drives: 2011 X3 35i Join Date: Jun 2011 Location: Boston iTrader: (0)	All fuel sold in my state has 10% methanol. I buy Top Tier 93 octane as a general rule. I've never had the problem that you describe. I don't believe that it is related to methanol in your fuel.
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11-11-2015, 10:46 AM	#8
exon Private First Class 25 Rep 132 Posts Drives: 2014 X3 35i Jet Black! Join Date: Oct 2013 Location: NJ iTrader: (0)	i have this on cold start. goes away very quickly after startup though.
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01-25-2024, 09:03 AM	#9
Sabean Registered 0 Rep 2 Posts Drives: 2013 x3 28i Join Date: Jan 2024 Location: STL iTrader: (0)	I also have the same issue with My x3 Only does it on a cold start in the winter time. After it runs for about 10 minutes it’ll go back to perfect and it never throws the code. It’s got a new battery in it it did it and it did before the new battery installed mass sensor air filter. The oil filter doesn’t have any leaks on the cap. I’m at a loss I need to know what to look for.
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01-30-2024, 04:45 AM	#12
chris55552 Private 36 Rep 85 Posts Drives: 2017 BMW x3 35i Join Date: Jul 2023 Location: alexandra LA iTrader: (0)	I have a brand new replacement n55 with less than 5k miles on it in my 2017 and it starts up and fluctuates briefly and sounds pretty loud and gnarly, but within 20 to 30 seconds calms down and sounds more civilized. If yours is fluctuating beyond that I would look at the Mass air flow sensor, cleaning it or replacing it and I think the vanos solenoids could be to be blame. Def check the air filter, mass air flow sensor, and MAP sensor.
	Appreciate 0 Quote

02-07-2024, 09:44 AM	#13
Houranimd49 First Lieutenant 251 Rep 332 Posts Drives: F10 535i xDrive, F25 xDrive35i Join Date: Apr 2019 Location: MI iTrader: (0) Garage List 2012 BMW X3 xDriv ... [9.25] 2011 BMW 535i xDrive [9.50]	Over the last several N55s I’ve had, they all did this. It wasn’t always, but they did do this every one in a while. They can be moody motors. But it was nothing ever concerning to me because they all ran just fine and even then the fluctuations were minimal, <+/-100rpm, nothing crazy. Based on my experience, I wouldn’t worry about it.
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