330i odd throttle behaviour

quattrogmbh · 06-14-2007, 12:25 PM

Not sure if this is a problem or whether I just haven't noticed it before

In neutral, when slightly applying gas, maintaining a constant pedal position, the revs start to climb. As they approach 1500rpm, they start to fall again to about 1200-1300rpm. Gas pedal hasnt moved..

Anyone else experience this?

Tried it a couple of times, so I'm not imagining it :-)

SoYank · 06-14-2007, 03:51 PM

I haven't noticed your phenomenon but I have noticed that my 330i has a surge at 4000 rpm in 1st and 2nd and sometimes in 3rd gear. It is a noticeable kick, too.

quattrogmbh · 06-14-2007, 04:27 PM

I believe 4000rpm is when the variable valve timing (Valvetronic) kicks in.

AndrewAZ · 06-14-2007, 04:41 PM

Could it be your torque converter locking up? Most auto transmissions dont lock the torque converter until mid 1st gear or 2nd gear. Which means off the line you can be accelerating with a stable RPM if you have a nice soft touch on the pedal since basically the torque converter is locking but that only lasts for a second at max.

voltron1011 · 06-14-2007, 05:17 PM

Quote:

Originally Posted by quattrogmbh

I believe 4000rpm is when the variable valve timing (Valvetronic) kicks in.

BMW's valvetronic is always on and has infinite stages, so there is no kick-in like on Hondas and Toyotas.

voltron1011 · 06-14-2007, 05:20 PM

It probably has something to do with polution control and the drive-by-wire system. The computer (on some cars) delays the return to idle because it was found that there is a lot of polution getting kicked out during that time.

Richwm · 06-14-2007, 05:21 PM

Quote:

Originally Posted by SoYank

I haven't noticed your phenomenon but I have noticed that my 330i has a surge at 4000 rpm in 1st and 2nd and sometimes in 3rd gear. It is a noticeable kick, too.

So does mine and the dealer says its normal but it doesnt seem right to me.

GregL · 06-14-2007, 05:42 PM

Quote:

Originally Posted by voltron1011

It probably has something to do with polution control and the drive-by-wire system. The computer (on some cars) delays the return to idle because it was found that there is a lot of polution getting kicked out during that time.

+1 I was about to say the same. Our cars aren't running a fixed cable from the gas pedal to a butterfly valve in the throttle body, it's all interpreted in between by a computer.

BK · 06-14-2007, 08:14 PM

Quote:

Originally Posted by voltron1011

BMW's valvetronic is always on and has infinite stages, so there is no kick-in like on Hondas and Toyotas.

You'd think that would be true, but there are definitely two "surges" noticeable on the 330i. I know they've been discussed here before. You have to accelerate slowly to feel them -- the first from 2800-3000, the second from 4000-4200. If you accelerate quickly, you blow right through them, so you can't really feel it.

As for the idling and slowly raising revs, I'll have to try that. It does sound like a drive by wire thing.

smellthebeans · 06-14-2007, 10:58 PM

Hmmm

I always considered it normal...as I have no other frame of reference.

Richwm · 06-15-2007, 10:43 AM

Quote:

Originally Posted by smellthebeans

Hmmm

I always considered it normal...as I have no other frame of reference.

My 01 330 doesnt do it so that is my reference.

voltron1011 · 06-15-2007, 10:57 AM

Quote:

Originally Posted by BK

You'd think that would be true, but there are definitely two "surges" noticeable on the 330i. I know they've been discussed here before. You have to accelerate slowly to feel them -- the first from 2800-3000, the second from 4000-4200. If you accelerate quickly, you blow right through them, so you can't really feel it.

.

What you're feeling is the 3-stage intake manifold transitioning from it's low-medium-high stages. That has nothing to do with Valvetronic.

http://en.wikipedia.org/wiki/Valvetronic

voltron1011 · 06-15-2007, 11:38 AM

Quote:

Originally Posted by Richwm

My 01 330 doesnt do it so that is my reference.

Your 01 doesn't do it because it was still drive-by-cable.

That's why the E46's seem so much more responsive and faster than the e90's (in my opinion).
One of my friends had a 01 330 and it just always seemed faster than my car even though we had identical horsepower.

Richwm · 06-15-2007, 11:51 AM

Quote:

Originally Posted by voltron1011

Your 01 doesn't do it because it was still drive-by-cable.

That's why the E46's seem so much more responsive and faster than the e90's (in my opinion).
One of my friends had a 01 330 and it just always seemed faster than my car even though we had identical horsepower.

The e46 is where they introduced drive by wire, I am 100% sure my 01 is drive by wire because my throttle control solenoid had to be replaced a couple years ago.

BK · 06-15-2007, 01:25 PM

Quote:

Originally Posted by voltron1011

What you're feeling is the 3-stage intake manifold transitioning from it's low-medium-high stages. That has nothing to do with Valvetronic.

http://en.wikipedia.org/wiki/Valvetronic

Thanks for the explanation.

voltron1011 · 06-15-2007, 02:10 PM

Quote:

Originally Posted by Richwm

The e46 is where they introduced drive by wire, I am 100% sure my 01 is drive by wire because my throttle control solenoid had to be replaced a couple years ago.

You're correct. I just noticed that 01 was the first year of DBW. Maybe my friend's car was a 2000 328 instead..?..?

06-14-2007, 12:25 PM	#1
quattrogmbh Captain 23 Rep 635 Posts Drives: BMW Join Date: Apr 2007 Location: Location iTrader: (0)	330i odd throttle behaviour Not sure if this is a problem or whether I just haven't noticed it before In neutral, when slightly applying gas, maintaining a constant pedal position, the revs start to climb. As they approach 1500rpm, they start to fall again to about 1200-1300rpm. Gas pedal hasnt moved.. Anyone else experience this? Tried it a couple of times, so I'm not imagining it :-)
	Appreciate 0 Tweet Quote

06-14-2007, 03:51 PM	#2
SoYank Major General 571 Rep 7,519 Posts Drives: 2009 E90 335i MT Join Date: Mar 2006 Location: Vinton, Virginia iTrader: (1) Garage List 2009 BMW E90 335i S ... [9.00]	I haven't noticed your phenomenon but I have noticed that my 330i has a surge at 4000 rpm in 1st and 2nd and sometimes in 3rd gear. It is a noticeable kick, too. __________________ **2009 E90 335i Montego Blue · Black Leather · Burl Walnut · 6MT · US Spec** SatNav • ZPP • ZCW • 6FL • TPMS • iDrive • PDC • HWS • Xenons • BMW Assist • Power Rear Sunshade • Logic 7 European Taillights • Rear Foglamp • OEM Alarm • PicoTray • DataToys XM-DVR • Multi-view Processor Quaife ATB LSD • Short Shift Knob • Hartge Anti-Roll Bars • AP Racing Front Brakes • 19" Style 269
	Appreciate 0 Quote

06-14-2007, 04:27 PM	#3
quattrogmbh Captain 23 Rep 635 Posts Drives: BMW Join Date: Apr 2007 Location: Location iTrader: (0)	I believe 4000rpm is when the variable valve timing (Valvetronic) kicks in.
	Appreciate 0 Quote

06-14-2007, 04:41 PM	#4
AndrewAZ Major 137 Rep 1,243 Posts Drives: 335i Join Date: Jan 2007 Location: CA iTrader: (0)	Could it be your torque converter locking up? Most auto transmissions dont lock the torque converter until mid 1st gear or 2nd gear. Which means off the line you can be accelerating with a stable RPM if you have a nice soft touch on the pedal since basically the torque converter is locking but that only lasts for a second at max.
	Appreciate 0 Quote

06-14-2007, 05:20 PM	#6
voltron1011 Colonel 119 Rep 2,909 Posts Drives: 2011 135i, FJR-1300 Join Date: Apr 2005 Location: Wiesbaden iTrader: (2)	It probably has something to do with polution control and the drive-by-wire system. The computer (on some cars) delays the return to idle because it was found that there is a lot of polution getting kicked out during that time.
	Appreciate 0 Quote

06-14-2007, 10:58 PM	#10
smellthebeans Lieutenant Colonel 87 Rep 1,555 Posts Drives: LPCs Join Date: Dec 2006 Location: San Antonio iTrader: (2) Garage List 1990 325i [0.00]	Hmmm I always considered it normal...as I have no other frame of reference.
	Appreciate 0 Quote