jerking during accelaration at low speeds

[desertfox65]

The car seems to have a jerking motion at speed of 60km/h ( 38mph) and 1500rpm when accelerating, mostly if this speed is sustained for some time. It is more apparent in the mornings. Sometimes this jerking can be violent if accelerating suddenly from a stop and go traffic situation.

BMW had a look at it and they fortunately saw it as well

, there was a BMW engineer from Germany who had a look at it and recommended that valve lift be increased, to improve the fuel mixture, which they did. However on way to work in slow traffic the jerking has re-appeared .

The SA was not too confident that changing the valve lift would sort things out, however he asked me to try. They beleive it is the engine not the the auto transmission.

If any of the forummer faced a similar issue, I would like to know if this was resolved.,Even if the similar symptom happened on another model. BMW has upgraded the s/w to the latest version and reset the transmission and throttle maps.

 

[Shirlene Fan]

Re: jerking during accelaration at low speeds

Yes, I experienced some jerking motion if I stepped on the brake pedal too hard to a stop and thereafter released it to step on the accelerator. It is normal, in other makes as well. Try warming up the engine longer before you move off from your parking lot.

 

[Bmer]

Re: jerking during accelaration at low speeds

How old is your car...after sending in your car a few times and problem still exist, maybe is time to change your gear box....
Do u encounter the same problem when u driving it manually??

 

[fooman700]

Re: jerking during accelaration at low speeds

The car seems to have a jerking motion at speed of 60km/h ( 38mph) and 1500rpm when accelerating, mostly if this speed is sustained for some time. It is more apparent in the mornings. Sometimes this jerking can be violent if accelerating suddenly from a stop and go traffic situation.

BMW had a look at it and they fortunately saw it as well

, there was a BMW engineer from Germany who had a look at it and recommended that valve lift be increased, to improve the fuel mixture, which they did. However on way to work in slow traffic the jerking has re-appeared .

The SA was not too confident that changing the valve lift would sort things out, however he asked me to try. They beleive it is the engine not the the auto transmission.

If any of the forummer faced a similar issue, I would like to know if this was resolved.,Even if the similar symptom happened on another model. BMW has upgraded the s/w to the latest version and reset the transmission and throttle maps.

I believe I know what you mean, it is like the car is holding on to 2nd gear for a longer time and when it decides to shift to 3rd, the car sort of jerk forward, at times violently. It is more apparently at DS mode. The ppl at PML has uplifted some s/w and claimed they have nipped the problem but alas it is still recurring. It is irritating that they don't "feel" the problem despite several road tests. They checked my trans oil and found it to be in good condition. My bro has his 5 series trans oil flushed, despite being in good condition, and the gear changes are smoother now. I asked for mine to be flushed as well, to determine the fault/symptom but process of elimination, but they claimed there is no PUMA case for the 3 series :furious:

 

[centurion]

Re: jerking during accelaration at low speeds

Sure seems to be a sticking throttle to me! Translated to Valvetronic-speak, I would suspect that this has something to do with the valvetronic and the associating sensor readings. Something may be giving weird readings to the valvetronic causing the acutator motor to do weird stuff. If it's just the valvetronic motor, easy, but I suspect that it's the sensors or the wiring loom.

 

[desertfox65]

Re: jerking during accelaration at low speeds

Cayman yes I believe it is valvetronic sensor issue. There is an eccentric cam sensor which controls the valvetronic motor. I have read in forums in UK and south africe that they had a loss of acceleration and jerking in cold weather, since Singapore is never that cold I suspect the problem exists, although to a lesser extent. I also told the BMW technical people I suspected something wrong with throttle mechanism since if I engage cruise control it seems to stabilize. I am waiting for BMW to come back to me if they agree on the conclusion. THe car has 7000Km only and I had this problem since the start, initial I though it would correct itself but it didnt, now finally 3 people in PML have verified and thankfully obeserved the phenomenon. I am almost positive that this is not related to brakes or transmission. Since i have another symptom that the accelaration is sometime very smooth and at other time is suddenly sluggish and the car seems to have a vibration, stepping of the gas pedal and stepping on it again corrects things. I put it up in the forum to see if any other forum member gone through this issue so far..

 

[Bmer]

Re: jerking during accelaration at low speeds

I encounter it exactly like what u mentioned....after leaving my car there for couple of weeks...problem solve(hopefully won't come back)....

Solution...Change transmission/gear box.....

Dunno whether they really found out what's the problem that's causing this to happen or they just assume is the transmission...anyway after changing it...seems to be fine..so far so good....just hope it continue....hope this info helps.

 

[hetraa]

Re: jerking during accelaration at low speeds

Encountered this too, did the software update and throttle values reset and it recurs.
cant be fixed la...seems very common on 320, 520.
But this doesnt happen on sports mode and manual..so D is history now.

Whats the name of the German engineer u spoke to?

 

[hetraa]

Re: jerking during accelaration at low speeds

u changed yr trans under pml warranty?

I encounter it exactly like what u mentioned....after leaving my car there for couple of weeks...problem solve(hopefully won't come back)....

Solution...Change transmission/gear box.....

Dunno whether they really found out what's the problem that's causing this to happen or they just assume is the transmission...anyway after changing it...seems to be fine..so far so good....just hope it continue....hope this info helps.

 

[desertfox65]

Re: jerking during accelaration at low speeds

I confirm it happens in sports mode as well, it is as if the car is cutting out for a very short period of time so it bucks and then recovers so you have a motion that I can only describe as hesitation then forward then hesitation and forward again until you accelerate more ,the car heats up and mostly the phenomenon is gone. The only time it doesnt happen when engine is cold, is when cruise control is engaged, so in my opinion it might not be transmission. I am still waiting for BMW/PML for their response.

 

[Bmer]

Re: jerking during accelaration at low speeds

u changed yr trans under pml warranty?

Yup, under warranty

 

[gadgets]

Re: jerking during accelaration at low speeds

I encounter it exactly like what u mentioned....after leaving my car there for couple of weeks...problem solve(hopefully won't come back)....

shit, no joke! how long was it in there exactly? and they gave u a loan car during the time it was in?

 

[hetraa]

Re: jerking during accelaration at low speeds

for mine, in sports mode, this doesnt happen. anyway bmer changed his trans under warranty and it solved it...definitely is transmission problem..u need to bang the table harder or else PML will just stall for time. or they'll leave yr car inside for weeks and not fix the prob, pissing u off so u wont go back.

I confirm it happens in sports mode as well, it is as if the car is cutting out for a very short period of time so it bucks and then recovers so you have a motion that I can only describe as hesitation then forward then hesitation and forward again until you accelerate more ,the car heats up and mostly the phenomenon is gone. The only time it doesnt happen when engine is cold, is when cruise control is engaged, so in my opinion it might not be transmission. I am still waiting for BMW/PML for their response.

 

[Bmer]

Re: jerking during accelaration at low speeds

shit, no joke! how long was it in there exactly? and they gave u a loan car during the time it was in?

they actually only took two three days to change and testing...but waiting for the parts to come and waiting for pml asia to give the green light total couple of weeks...first wk no car...second week loan car.

for mine, in sports mode, this doesnt happen. anyway bmer changed his trans under warranty and it solved it...definitely is transmission problem..u need to bang the table harder or else PML will just stall for time. or they'll leave yr car inside for weeks and not fix the prob, pissing u off so u wont go back.

Actually no need to bang table la...I used to hate the SA over at pml as like what u said "bang table harder" then they will take action...but then for this current transmission issue, i totally change my view abt them...(imo, i think is cause quite a number of Old Bird SA left, now mostly new blood), attitude wise service wise much much better. Hopefully will con't to be lidat...

 

[desertfox65]

Re: jerking during accelaration at low speeds

I just got a message from pml they are discussing issue with BMW and technical manager. In fact I did not bang table at all. PML s cusotmer relation manager is following up this case with the concerend engineers and BMW. Hopefully I should get an answer today. I did get a loner car first time when they kept it in for 3 days few weeks ago.

 

[gadgets]

Re: jerking during accelaration at low speeds

they actually only took two three days to change and testing...but waiting for the parts to come and waiting for pml asia to give the green light total couple of weeks...first wk no car...second week loan car.

I just got a message from pml they are discussing issue with BMW and technical manager. In fact I did not bang table at all. PML s cusotmer relation manager is following up this case with the concerend engineers and BMW. Hopefully I should get an answer today. I did get a loner car first time when they kept it in for 3 days few weeks ago.

sorry, the car is road worthy before the change right? so why cant they let u drive it while they sought out the logistics instead of leaving it pml? we paid a bomb for the car to drive, and not be inconvenienced...

 

[hetraa]

Re: jerking during accelaration at low speeds

how did u get them to change yr transmission? had to go back PML a couple of times with the same issue?



Actually no need to bang table la...I used to hate the SA over at pml as like what u said "bang table harder" then they will take action...but then for this current transmission issue, i totally change my view abt them...(imo, i think is cause quite a number of Old Bird SA left, now mostly new blood), attitude wise service wise much much better. Hopefully will con't to be lidat...[/quote]

 

[blinded]

Re: jerking during accelaration at low speeds

I cannot imagine an automatic gearbox having jerks under constant speed, meaning if there are no gear changes involved. All clutches are closed under that conditions and it is more likely that it is related to the engine. Have you ever thought about the fuel quality?

 

[desertfox65]

Re: jerking during accelaration at low speeds

its esso/shell 98 or spc but always 98 octane fuel.

 

[blinded]

Re: jerking during accelaration at low speeds

Fuel bought in Malasyia or in Singapore? I don't trust the stuff from Malaysia - bad experience myself!