Low idle RPM issues

Exclusive · 05-07-2013, 07:34 PM

I have a 2006 330i that just developed a low idle issue the other day. I did an oil change, and the car was fine, but shortly thereafter, we had a major downpour of rain. I dont know if this is in any way related, but figured I would mention it.

THe car runs and drives fine. Has the correct amount of power, no check engine lights, and runs smoothly. When it starts, the engine RPm is right around 725rpm and feels normal. After about 30 seconds, the rpms fall to about 525 and i feel a slight vibration in the cabin from the low rpm. if I turn the a/c on, the rpms increase to about 650-700 and the car feels fine.

I have followed the reset procedure on the throttle body and made sure the intake filter is clean and secure. Any ideas on what is causing my car to randomly drop RPMs at idle? Thanks.

EatsRainbows · 05-07-2013, 07:37 PM

Quote:

Originally Posted by Exclusive

I have a 2006 330i that just developed a low idle issue the other day. I did an oil change, and the car was fine, but shortly thereafter, we had a major downpour of rain. I dont know if this is in any way related, but figured I would mention it.

THe car runs and drives fine. Has the correct amount of power, no check engine lights, and runs smoothly. When it starts, the engine RPm is right around 725rpm and feels normal. After about 30 seconds, the rpms fall to about 525 and i feel a slight vibration in the cabin from the low rpm. if I turn the a/c on, the rpms increase to about 650-700 and the car feels fine.

I have followed the reset procedure on the throttle body and made sure the intake filter is clean and secure. Any ideas on what is causing my car to randomly drop RPMs at idle? Thanks.

my car does the same thing, i always thought it was normal o.o
maybe someone could help us out here, didn't try the thing with the a/c tho, but it would make sense since a/c costs alot of energy

ssmith96 · 05-07-2013, 07:47 PM

The A/C will make the RPM go up, i think my avg idle is 600rpm, maybe run a bottle of jectron through when you reach 1/2 tank and see if that helps, it cleaned up my rough idle a little

GMe90 · 05-08-2013, 09:08 AM

I have the opposite problem. When I turn the car on, the rpms jump to about 1000 rpm, stay there for a bit. After I start driving and come to a complete stop, the idle returns to the normal 600 rpm range.

335speed · 05-08-2013, 02:54 PM

Mine starts at a 1000 and drops to 600 RPM as well. Thought it was normal but I read a post on here somewhere where some people tried to get it fixed and it was a nightmare... Id say just dont sit anywhere long enough to notice it!

GoRomeo · 05-08-2013, 03:02 PM

There is a few things you can also do...

I would check the following:

Air Filter-replace if its dirty
Clean MAF sensor
Replace spark plugs in you havent.
Clean and swap Vanos solenoids.
add jectron like mentioned above
Check coils for misfires? or replace them if necessary

You have a lot of work to do for now... and check back with us.

05-07-2013, 07:34 PM	#1
Exclusive Private First Class 11 Rep 126 Posts Drives: 2007 E92 335i Montego/Saddle Join Date: Jan 2012 Location: Pompano Beach iTrader: (0)	Low idle RPM issues I have a 2006 330i that just developed a low idle issue the other day. I did an oil change, and the car was fine, but shortly thereafter, we had a major downpour of rain. I dont know if this is in any way related, but figured I would mention it. THe car runs and drives fine. Has the correct amount of power, no check engine lights, and runs smoothly. When it starts, the engine RPm is right around 725rpm and feels normal. After about 30 seconds, the rpms fall to about 525 and i feel a slight vibration in the cabin from the low rpm. if I turn the a/c on, the rpms increase to about 650-700 and the car feels fine. I have followed the reset procedure on the throttle body and made sure the intake filter is clean and secure. Any ideas on what is causing my car to randomly drop RPMs at idle? Thanks.
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05-07-2013, 07:47 PM	#3
ssmith96 Banned 78 Rep 1,038 Posts Drives: 07 328xi Join Date: Mar 2013 Location: Long Island, NY iTrader: (2)	The A/C will make the RPM go up, i think my avg idle is 600rpm, maybe run a bottle of jectron through when you reach 1/2 tank and see if that helps, it cleaned up my rough idle a little
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05-08-2013, 09:08 AM	#4
GMe90 Captain 356 Rep 928 Posts Drives: 2007 328i Coupe, ZSP, Premium Join Date: Feb 2013 Location: Knoxville iTrader: (0) Garage List 2003 BMW Z4 3.0i [6.00] 2007 BMW 328i [10.00]	I have the opposite problem. When I turn the car on, the rpms jump to about 1000 rpm, stay there for a bit. After I start driving and come to a complete stop, the idle returns to the normal 600 rpm range.
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05-08-2013, 02:54 PM	#5
335speed Private First Class 12 Rep 193 Posts Drives: 16 550 Join Date: May 2013 Location: SoCal iTrader: (0) Garage List 2007 BMW E90 [10.00]	Mine starts at a 1000 and drops to 600 RPM as well. Thought it was normal but I read a post on here somewhere where some people tried to get it fixed and it was a nightmare... Id say just dont sit anywhere long enough to notice it!
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05-08-2013, 03:02 PM	#6
GoRomeo Brigadier General 958 Rep 3,840 Posts Drives: 330i, 135i Join Date: Feb 2006 Location: San Diego CA iTrader: (0) Garage List 2008 BMW 135i [9.50] 2006 330i [6.75]	There is a few things you can also do... I would check the following: Air Filter-replace if its dirty Clean MAF sensor Replace spark plugs in you havent. Clean and swap Vanos solenoids. add jectron like mentioned above Check coils for misfires? or replace them if necessary You have a lot of work to do for now... and check back with us.
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