[prepster]

Hello everyone, i just purchased my first bmw, its a 2007 bmw 335i with sport and premium package and an automatic transmission. I absolutely love the car but have a couple questions. Im a newbie here so please dont flame on me, ive done a lot of searching already througout this forum and others but couldnt get a definite idea on what the problem could be. here goes

1) Its been covered before but my situation is a little different...When accelerating from a stop i do feel the car hesitate to get started, which the Neutral Idle Control makes sense to me, but then every once in a while the car will lunge or shift firmly during first and second gear while accelerating gradually...what can cause that to happen? and is it something what can ruin the transmission/engine?

2) Also, when the car is on and the radio and ac is off, i hear a buzzing noise coming from the right passenger side. Then the buzzing noise goes away, similar to the buzzing noise that you hear from the engine when the car is turned off. Any idea on what this could be?

Any help would really be appreciated since i just purchased this car and it has 68k miles on it with no extended warranty. I have already replaced the hpfp, did an oil change, and completed the maintaince up to date with the car, i just have to drain and refill the trans in the next oil change, thanks again for any help.

[jdbretz]

I am just guessing here cause I don't have an automatic, but when I have driven BMW automatics, it seems like there is always a bit more of a lag when going from a stop if the vehicle is in D. If you change your gear selector to DS do you still have the issue with the hesitation? I'm not sure if BMW automatics starts in 2nd gear like a lot of Mercedes do, and when you put it in "Sport Mode" it starts in 1st.

As to the buzzing, I'm not sure. Does the buzzing change pitch with engine RPM? Can you describe in more detail when it happens, what if anything makes it stop, is it only when the car is hot or cold, etc?

[RambleJ]

Since you purchased a used car, the car is adapted to the previous owners driving style and it sounds like they used to bang on the pedal pretty hard. You can reset the transmission adaptation by putting your car in awake mode (putting the key in the ignition and pressing the ignition button without having your foot on the brake). Once you have done this all your electrical should be on, now press and hold the gas pedal all the way down for a little over 30 seconds, this should rest your tranny. Then try and drive it and see if this still happens.

[Syndicategt]

If I can recall, my car would lag off the stop a year back. BMW updated the cars software and that seemed to fix the problem. The buzzing noise you hear can be just about anything, have the dealership look at it. The buzz you hear when the car is off is the ECU fan.

[prepster]

Originally Posted by jdbretz

I am just guessing here cause I don't have an automatic, but when I have driven BMW automatics, it seems like there is always a bit more of a lag when going from a stop if the vehicle is in D. If you change your gear selector to DS do you still have the issue with the hesitation? I'm not sure if BMW automatics starts in 2nd gear like a lot of Mercedes do, and when you put it in "Sport Mode" it starts in 1st.

As to the buzzing, I'm not sure. Does the buzzing change pitch with engine RPM? Can you describe in more detail when it happens, what if anything makes it stop, is it only when the car is hot or cold, etc?

Yeah if if I move to sport mode the car still lags for a couple seconds to get from a stop, id say about 3 seconds, and the firm shift is still there iwhen shifting to the first and second gear about 75% of the time, especially going up hill.

The buzzing does not change pitch with engine rpm. It happens after the car is warmed up and then goes away after driving for a certain amount of time. You can hear a similar buzzing noise after the car is off and parked. The sound comes from the right passenger side of the engine.

Originally Posted by RambleJ

Since you purchased a used car, the car is adapted to the previous owners driving style and it sounds like they used to bang on the pedal pretty hard. You can reset the transmission adaptation by putting your car in awake mode (putting the key in the ignition and pressing the ignition button without having your foot on the brake). Once you have done this all your electrical should be on, now press and hold the gas pedal all the way down for a little over 30 seconds, this should rest your tranny. Then try and drive it and see if this still happens.

thanks for the info, i will give it a try later today.

[prepster]

Originally Posted by Syndicategt

If I can recall, my car would lag off the stop a year back. BMW updated the cars software and that seemed to fix the problem. The buzzing noise you hear can be just about anything, have the dealership look at it. The buzz you hear when the car is off is the ECU fan.

I think the buzzing noise while driving might be the ecu fan too since its the same type of noise, is the ecu fan periodically turning on and off while driving normal? Thanks alot for the input, i will see about getting the software updated.