dothack

No sure if this is a common thing with all cars that use drive by wire but i've driven a 06 s2000 with DBW and older 95-96 NSX's that have DBW and no lag.

Whenever im at a dead stop with the 525i I press the gas and the throttle just goes up and like sits there then all of a sudden it'll go, which to me is pretty dangerous if you want quick responsive throttle. When the cars in motion throttle response is fine. Just at dead stops it's horrible if your barely press it just to get some movement nothing it'll just rev up and then all of a sudden go finally.

Not sure if this is a common problem or is there a fix for this? Fix i mean from the dealer. this is a 2007 525i.

Hawkwing

If your car was a diesel I'd say it was a feature! That's what BMWUK tell me! - In my car (06-530d) this is due to the throttle control being taking away from the driver to support compliance with EU4 particulate emmissions - e.g the engine is controlled in building revolutions and engaging gear by the electronics not by how the driver squeezes the throttle in high demand/low speed situations, the delay is an outcome of this process - the effect may be encountered by pulling away from a stop as you describe or at low speed, circa 3-5mph, when entering a roundabout. However I'm not sure this is true of the petrol models, from your description this would appear to be similar/same issue though.

I agree its alarming and not acceptable, however I've been told (by BMWUK) that nothing is/can to be done on my (06-530d) car.

By the way, BMWUK state the effect can be minimised by altering one's driving style, phuffh! - the key point is they are unable to elaborate when pushed on this point, funny or what!!

dothack

Yes it's pretty bad when your use to instant response. Even if didn't want the instant response of quick throttle, just the smoothness of going from a stop to foward motion is pretty bad. It's not a smooth at all for me. I wouldn't mind the delay so much if it was smooth from the stop but when i press the gas even a little it just revs cause the cars not moving and then when the car finally wants to go and it goes then all of a sudden, and then it'll feel like the torque dropped like it's changing gears mid acceleration then go again.

The cars great in all other aspects except this, kinda makes you miss cable operated throttle. But i know for a fact that drive by wire can be smooth and feel like a throttle cable.....well other then the fact you kinda loose the feel of a cable operated throttle, but i know it can be pretty damn close you won't notice it considering i've driven cars where you woudln't be able to tell at all it's drive by wire.

sparky12

Funny that you mention this - I'm just into week two with my 2007 530 and I've been noticing the exact same thing. At first I thought it was my foot trying to get used to the new pedal and its action but even applying the throttle smoothly results in hesitation followed by a jump in acceleration once second gear is hit. Very odd. Can't help with mileage either I would assume.

Hawkwing

I suspect altering your throttle pressure will not help here, this reads the same as I described with my diesel 530d in that the car's management system has taken over from the driver.

I posted this a while back - from BMWUK I received this;

Quote "The perceived throttle delay you have experienced while driving is in fact the result of the compliance of the diesel engine control system and the automatic transmission with EU regulations of the particulate emissions. It only occurs in limited engine operating conditions at high torque requirements when a gear change is imminent. It is only apparent in certain driving styles."

Therefore it's my (our?) fault!! Read on...........

To continue, quote, "The system builds acceleration at a rate that prevents the excessive formation of soot particles that would be generated should full fuelling be permitted. Because of this control, the throttle is actually applied electronically by the engine management system and not directly by the driver. The effect is that the operation of the accelerator pedal can feel different due to the normal linear correlation between driver requirement and the throttle application being replaced by the necessarily non-linear system control. The system applies the throttle slower than expected at first, and then builds to the drivers load requirement. It is not possible to alter the throttle application under these driving conditions, as compliance with EU regulations must be maintained"

Now its the EU's fault!!

And here is the helpful advice part!

Quote "A slight alteration of driving style minimises the control necessary and avoids the effect" Very helpful, of course there is no actual advice as to what driving style too use! Funny (not really!) I thought I knew how to drive, I've been driving long enough, however according to BMW I don't know how to drive their car!!

It maybe that the petrol engine is being influenced in a similar fashion? You guys should probably get this checked out by your dealers - I recall driving a 550 recently (in the USA), I can't say I noticed this problem to any extent, certainly not to the level that I do with my 06-530d................

aybeesea

Maybe you need a small turbo to operate at low revs...



Seriously though, you could always bite your lip, ignore whose "fault" it is, and get a remap!

ABC

the-oneil

Or a 550i


Seriously though, I agree with you as I noticed the same with my previous 530d, not anymore with the 530i

BlaSTiWi

Rumor has it Sprintbooster will do the trick, it's not as good as a Supercharge, re-map ECU or kinda like but can nail down the delay.

Hawkwing

Absolutely true, well spotted ABC, a second turbo would be welcome, but that's being greedy!!

Re-map, ummmm..... I'm dangerous enough with what I have (well that's what the ex said )

However, should BMW 'kludge' (bodge) their vehicle managment systems to suit new (EU4) regulations?

I'm off to sample smoothness personified in my S500 (mind you, something will no doubt fall-off/break very soon, it's an MB after all!)

kchan

I would try couple things if you are in the US:
1. take out the charcoal filter (US cars only)
2. install sprint booster

i believe the 525i is a non-diesel? =D
i did both and it helped greatly. i also got a 2007 525i (manual) and from a rolling start it was very unresponsive. with these two changes it finally deserves the bmw name! for the charcoal filter, look at the parts and mods sub-forum and you will see it on the top. for sprint booster, it's a device that attaches in line with the accelerator, it improves throttle response/reduce lag, but doesn't make any more power. However with the improve response it definitely feels faster. charcoal filter removal is free (10 mins of your time), and sprint booster is ~$250. best things i've done to my car =) also see my review of sprint booster in the parts subforum as well (do a search on sprint booster)

hope that helps.