RPM Unstable

ArsenalFC · 09-04-2008, 05:21 AM

Hello, I recently picked up my E92 M3 which has 1600 miles, once in awhile the rpms will bounce up and down, especially with the AC on. Is that a problem? Anything I should worry about? It goes from 1000RPM to 1300RPM and down. Thanks for any input.

UltimateBMW · 09-04-2008, 08:25 AM

If this is while idling, its perfectly normal. My e46 330 does it all the time.

Romo · 09-04-2008, 08:36 AM

IMHO it is not normal, I have driven several BMW`s and my E92 M3 is on its way for next week, but idle is idle.

I did once see it on a Honda I had in the past; reving from idle to 13-1400 and back. This was obviously a mechanical problem and had to be fixed. And it was fixed. ( as far as I can remeber it was provoked by a dirty gas valve, I don`t know if this is the correct English word for it.)
Now a E92 M3 has 8 of them, maybe a problem overthere?

e46e92love · 09-04-2008, 10:55 AM

I believe its normal; happened from time to time in my e92 335i and my dad's 7. I think your fine, but if it bothers you mention it to your dealer and schedule an appointment.

!Xoible · 09-04-2008, 11:15 AM

normal when AC is on... AC sucks a lot of RPM depending when it works. AC turns on and off to control temperature so ur drops probably coincide with it working.

u can notice also if u have a 6MT and the AC is on, ur shifts will be jerkier. that's coz RPM's drop more rapidly...

sg///M3 · 09-04-2008, 11:21 AM

Not to thread-jack, but anyone else notice that when you turn the steering wheel while idling (stationary) the idle speed changes as well? I'm assuming that the power steering is putting some load on the engine?

!Xoible · 09-04-2008, 11:22 AM

Quote:

Originally Posted by sg///M3

Not to thread-jack, but anyone else notice that when you turn the steering wheel while idling (stationary) the idle speed changes as well? I'm assuming that the power steering is putting some load on the engine?

DCT and ur foot is on the brake?

sg///M3 · 09-04-2008, 11:25 AM

Both in neutral and in gear, and with either hand brake or foot brake.

bmstyle71 · 09-04-2008, 11:27 AM

Quote:

Originally Posted by Arsenal

Hello, I recently picked up my E92 M3 which has 1600 miles, once in awhile the rpms will bounce up and down, especially with the AC on. Is that a problem? Anything I should worry about? It goes from 1000RPM to 1300RPM and down. Thanks for any input.

Quote:

Originally Posted by sg///M3

Not to thread-jack, but anyone else notice that when you turn the steering wheel while idling (stationary) the idle speed changes as well? I'm assuming that the power steering is putting some load on the engine?

It is normal. The a/c compressor uses a lot of power and so does the power steering. Therefore, when you are at idle, any power that you exert on the engine must me compensated for otherwise, your engine will stall. That's why sometime when your a/c is full blast and your are idling, your car might shut off.

ArsenalFC · 09-04-2008, 11:48 AM

Thanks guys, everything you guys say that happens to your cars happens to mine, so I guess its normal because its happening to all of ours.

!Xoible · 09-04-2008, 11:58 AM

Quote:

Originally Posted by sg///M3

Both in neutral and in gear, and with either hand brake or foot brake.

beats me man

Quote:

Originally Posted by Arsenal

Thanks guys, everything you guys say that happens to your cars happens to mine, so I guess its normal because its happening to all of ours.

what annoys me about RPM's is after i smoothly engage gear and i roll, say im going 3k RPM and decide to push it some more, the car will jerk. i tried to do super smooth push on throttle but it still does the same.... and its waaay after gear is engaged and my foot is off the clutch... annoys me a lot. u'll see RPM's jumping 1k at a time, not smoothly

M2381 · 09-04-2008, 03:03 PM

I have also noticed this..it makes me feel like such a freaking noob when I'm shifting since I cant get a smooth shift 5~10% (1st to 2nd) of the times....especially when flooring it. Dont even get me started on red line 1st to 2nd gear shifts

Blake · 09-04-2008, 04:24 PM

i've noticed this as well. my 325 has done it too. i've just written it off as nothing really. i'm sure my neighbors don't like it coupled with my exhaust but oh well

Romo · 09-05-2008, 12:32 AM

Maybe it`s because off US petrol? ( Quality I mean)

I never ever heard anything about these things in the EU.

09-04-2008, 05:21 AM	#1
ArsenalFC Second Lieutenant Drives: \| DCT \| AW \| M3 \| Join Date: Sep 2007 Location: \| LV \| CA \| Posts: 280 iTrader: (0)	RPM Unstable Hello, I recently picked up my E92 M3 which has 1600 miles, once in awhile the rpms will bounce up and down, especially with the AC on. Is that a problem? Anything I should worry about? It goes from 1000RPM to 1300RPM and down. Thanks for any input. __________________ Arsenal F.C. - Gooner 4 Life
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09-04-2008, 08:25 AM	#2
UltimateBMW Brigadier General Drives: MP4 Join Date: Dec 2006 Location: South Posts: 3,290 iTrader: (0)	If this is while idling, its perfectly normal. My e46 330 does it all the time. __________________

09-04-2008, 10:55 AM	#4
e46e92love Colonel Drives: e92 ///M3; X3 (wife's) Join Date: Nov 2007 Location: The East Side of Things Posts: 2,990 iTrader: (0)	I believe its normal; happened from time to time in my e92 335i and my dad's 7. I think your fine, but if it bothers you mention it to your dealer and schedule an appointment. __________________ "...it's not about the money and not about the brand of the car, it's about handling,performance and passion......And that, no other car has all together like an M3........when you talk about the most complete car the M is invincible." --Tony Kanaan.

09-04-2008, 11:48 AM	#10
ArsenalFC Second Lieutenant Drives: \| DCT \| AW \| M3 \| Join Date: Sep 2007 Location: \| LV \| CA \| Posts: 280 iTrader: (0)	Thanks guys, everything you guys say that happens to your cars happens to mine, so I guess its normal because its happening to all of ours. __________________ Arsenal F.C. - Gooner 4 Life

09-04-2008, 03:03 PM	#12
M2381 Major Drives: E92 M3, GTI Join Date: Feb 2008 Location: FL Posts: 1,288 iTrader: (0)	I have also noticed this..it makes me feel like such a freaking noob when I'm shifting since I cant get a smooth shift 5~10% (1st to 2nd) of the times....especially when flooring it. Dont even get me started on red line 1st to 2nd gear shifts __________________ Last edited by M2381; 09-04-2008 at 05:42 PM.

09-04-2008, 08:36 AM	#3
Romo Captain Drives: 1M, HP4 Competition Join Date: Oct 2006 Location: The Netherlands Posts: 805 iTrader: (0)	IMHO it is not normal, I have driven several BMW`s and my E92 M3 is on its way for next week, but idle is idle. I did once see it on a Honda I had in the past; reving from idle to 13-1400 and back. This was obviously a mechanical problem and had to be fixed. And it was fixed. ( as far as I can remeber it was provoked by a dirty gas valve, I don`t know if this is the correct English word for it.) Now a E92 M3 has 8 of them, maybe a problem overthere?

09-04-2008, 11:15 AM	#5
!Xoible Banned Drives: .... Join Date: Nov 2006 Location: . Posts: 46,045 iTrader: (4) Garage List 2008 M3 [3.50] 2007 335i [4.50] 2008 528i [4.00] 2006 Infiniti - G35 ... [4.00]	normal when AC is on... AC sucks a lot of RPM depending when it works. AC turns on and off to control temperature so ur drops probably coincide with it working. u can notice also if u have a 6MT and the AC is on, ur shifts will be jerkier. that's coz RPM's drop more rapidly...

09-04-2008, 11:21 AM	#6
sg///M3 Lieutenant Drives: 2008 M3 DCT Join Date: May 2008 Location: Charlotte, NC Posts: 407 iTrader: (0)	Not to thread-jack, but anyone else notice that when you turn the steering wheel while idling (stationary) the idle speed changes as well? I'm assuming that the power steering is putting some load on the engine?

09-04-2008, 11:25 AM	#8
sg///M3 Lieutenant Drives: 2008 M3 DCT Join Date: May 2008 Location: Charlotte, NC Posts: 407 iTrader: (0)	Both in neutral and in gear, and with either hand brake or foot brake.

09-04-2008, 04:24 PM	#13
Blake Banned Drives: Chevy Aveo Join Date: May 2008 Location: Parent's Basement Posts: 4,655 iTrader: (7)	i've noticed this as well. my 325 has done it too. i've just written it off as nothing really. i'm sure my neighbors don't like it coupled with my exhaust but oh well

09-05-2008, 12:32 AM	#14
Romo Captain Drives: 1M, HP4 Competition Join Date: Oct 2006 Location: The Netherlands Posts: 805 iTrader: (0)	Maybe it`s because off US petrol? ( Quality I mean) I never ever heard anything about these things in the EU.

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