Hesitation issues.
 

Hi there,
I have a 4.8i with approx. 7,000 miles on it. I often get some hesitation when starting from a complete stop and also some lag before getting slammed into the back of my seat when trying to get around someone quickly in city driving maneuvers. I also note that sometimes it just doesn't accelerate smoothly - kind of choppy like I have bad gas or something.

What gives?

That's fairly normal for that engine.....put the shifter in sport mode and it's virtually gone........Phil

agreeance

Yes, it seems to be a transmission, rather than engine, issue.

it is mostly the x drive computer adjusting and analyzing traction. try staying in the throttle more often or feed the gas more judiciously. the more drastic the change the more likely the hesitation. even still i have the same issues from time to time.

BMW just hasn't got it right with the 6-speed automatics.

everything's fine in my 09 30i

http://forums.bimmerforums.com/forum...d.php?t=820069

drive by wire issues... (slow loading right now though)... I hate it too... coming from a '95 truck, the difference is night and day... hell I drive my dad's '02 minivan and the difference is huge... why can't they get it right? I almost gave up on the X5 because I felt the delay was bad during the test drives.

Yep, same problem here. Dealer tells me the transmission is in learning mode while driving, but seems it's a very slow learner - and makes me look like one too! Seriously, this is the worst feature of the 4.8i, and I'm really beginning to hate it after 20,000k's in 10 months.

We drive for 200k's at constant speed using the cruise control. Then we hit the first traffic light, and it thinks my dear old grandma is driving. I press a bit harder, nothing, a bit harder, nothing. Then all hell breaks loose! X5 lurching around like a drunk teenager, kids terrified and the wife screaming at me! All I wanted was something in between...

Sport mode will solve the problem, but plays hell with your fuel consumption. And I really don't appreciate having to change modes just to make a smooth exit from traffic lights - isn't that why I bought an automatic in the first place? Never had this problem with any other car.

I feel your frustration, but can't offer a solution other than clear it's memory (ie. give it a good flogging and tell it who's boss). Might be just my imagination, but sure feels better afterwards!!

You need to do 2 things : (a) put shifter in "DS" (sport) mode, or (b) firmly press gas pedal down, dont hesitate when doing that, show it some assurance in what you do - works like a charm for me !

Is that the same as

Agreed, it works!

if you read some of the literature on the E70 xdrive, you will find out that the all wheel drive system is a "proactive" system that calculates traction and accelerator movement to best apply the tourque and power before the car starts to move- Flexray can make it happen in 0.1 seconds (100 ms). If you find that when you depress the gas pedal suddenly and the car hesitates for about 0.1 sec, you know its the xdrive working properly for you so you don't get the mad back end sliding.

If the hesitation is longer than that, i'd an engine issue.

When I first started to drive my 4.8i it did experience the hesitation. I'd press on gas, wouldn't move, so i'd give it more, then just BOOM! shoots forward, then I panic and pull my foot off the pedal, and the car jerks and everything inside it ... then other people wonder if I've gone mad :)

I have my doubts.. I ve tried lots of techniques but IMO this transmission is one of the worst I 've come across and its my second X5 .. can I Have my old 4.6 back please :trustme:

Serious question...when you say "not moving...is the car literally "not moving" or just not "peppy"???:dunno:

from the thread I posted, a BMW technician quoted:

It learns but only during the drive... it is not stored in memory once the vehicle is turned off. 4 different techs contributed to that thread.

No, it can't be the xDrive system. Folks with E53s and pre-facelift X3s have no hesitation problems at all with their cars.

Not to get overly technical, but here's some pointers on xDrive:

1. When starting off, the differential is fully locked to optimise traction.

2. When doing parking maneuvers (large steering angles below 20km/h), the xDrive is decoupled to be rear-wheel drive to reduce driveline forces when parking.

3. After starting off as the vehicle gains speed over 20km/h, the xDrive splits the torque 40/60 default, unless other factors warrant a change in distribution

There isn't a "magical" redistribution of power when you accelerate, and hence, there isn't any reason for xDrive to cause any hesistation or delay. And like I said, it works perfectly fine in my X3 or any of the older BMWs.

It's the gearbox. BMW hasn't bothered to iron out the 6AT issues on the 328xi, 2007+ X3, or X5 for some reason.

yes, it won't move. well, doesn't happen now that I'm more used to the car but yea i'd push on and it won't move (engine revs, but car doesn't move) for a split second- notice it if i want to really quickly turn-in to a street or likewise.

Hmm.., Yeah i've been thinking it's the Xdrive thinking, I guess more specifically the "AGS" specified in rh71's post. But I may be wrong.

but then again, these "problematic" transmissions are all on Xdrive vehicles according to your post...

Bottom line, I hardly notice it anymore. I did get an iDrive upgrade since then..

I thought I read somewhere or saw on a post that when it starts off, its in second (2nd) gear and not first, call it a fuel economy factor. If you put it in "DS" then it gets more lively. I tried to sense the shifting and yes, it seems that for the 4.8 it does start off in two. May explain the so called "hesitation".

you are wrong, the hesitation is not on 2nd gear starts because my 135i starts on 2nd gear on auto mode and there is no hesitation at all. the car pulls like a crazy on 2nd gear.

my 09 E70 3 day old has the exact problem. i bet its the transmission.
i will call my SA on this and probably there is a software update on this problem

i suspect the reason for the hesitation is that in normal D mode, it starts off in 2nd and if you punch on the gas the car has to downshift to 1st to accel.

in DS it just goes from 1st and no hesitation.

Had the same problem on my 08 3.0 si. Reported it to the dealer and had it booked in for that and other issues.

The delaer reported no fault (surprise, surprise) and just reset the learning module.

I must say though, since then I have not experienced the lag!

My theory is that when your car is new most people tend to 'baby' their car and are very gentle on the throttle (running in the engine). Hence the car thinks its your granny driving it. Since the reset I have not had to pay attention to the running in process and give the gas a bit of welly. Therefore the transmission is now learning my usual driving habits.

Does this make any sense? But since the reset, have noticed huge improvement.

well, makes intuitive sense. But as per the BMW technical manual (there's a link to it here on the forum somewhere) the transmission shifting profile is not saved or stored long-term in the car; it's programmed to respond to the driver's input each and every time the car is being driven separately. So I'm not sure what the issue can be but my 4.8i got the reset again but it still shifts roughly when coming to a slow steady stop.

ie- coming to a red light, I brake smoothly and the car just before it comes to a complete stop, it downshifts and all our heads jerk forward- as if i stepped on the brake like a panicky 5 year old.

i just use the steptronic to do shifting and it's not a problem.. so maybe it has more to do with gear selection as some people pointed out rather than drive by wire and delay

I have a 09 X5 4.8 with about 10k km on it. I feel the lag a lot. I will push the accelerator down, and the car will hang there and then finally throw me back. When going slow, the car jerks a lot as well. It is the same in DS, although it is a little faster and louder. I see myself switching many times between D and DS during my drive.

BTW, is the DS supposed to stop faster? When I am driving slow in traffic and take my foot of the brake to let the car roll, it seems to stay steady until I push the accelerator. Then when I take my foot of both, the car starts noticeably slowing down on its own (As if the break is being pushed) unlike the normal D.

I have the same problem with my 08 4.8i. When slowing down to a red light, it downshifts sending a jerk to otherwise smooth ride.

I experience a lag when starting to move. Just like somebody else described above. I push the pedal, no reaction. I push harder, still no perceivable or anticipated motion. I push a little harder and it lurches forward as if I dropped the clutch on a manual gearbox.

Hope this can be cured with transmission firmware reflash (if there is any).

There's an option to reset the tranny computer isn't there I did it once .. to set it back to "unlearnt' Mode ?

From the E60 forums.. worth a try I did it once...

You put your key in/hit start ONCE so the electronics of the car come on but it is not started.

Then hold down the gas, past the downshift point to the floor for 25-30 seconds straight.

If you listen, at about 25s exactly you will hear some "noise" and that is the tranny "resetting" itself to factory specs

Wow! Never though it would be so easy. I will give it a try later when I
leave the parking lot from my office.

Thanks, James.

I tried this on the wknd but I did not hear a click. Perhaps only for the E60??

Yeah, I tried yesterday and did not hear anything. Maybe my ears have some problem?

I am not sure if the tranny has been reset or not.

But, still thank you for sharing.