Hesitation when accelerating ?

[coupe-sport]

me too, me too ... i especially notice it when going from 1st to 2nd, when hitting the throttle hard

Yep that's it - its first to second when it can really hesitate - i did wonder as it seems to do it more when the fuel tank is under half full if the fuel was moving away from the pickup and fuel pressure was temporarily dropping. Its going to visit the dealer very soon as my oil level gauge seems to show different readings every day

I'll let you know what the dealer has to say

Cheers

James

[WLH]

eddieo welcome to the forum...

[E85]

thx James, let us know is that is the issue ... i tried to different ways of driving (ie. hard vs not and everything in between) and when driving like a tame driver, where i accelerate like the rest of the world and shift at about 3-4k rpm, no issues

when i pin the throttle in 1st up to 6k and then shift hard to 2nd, i notice the the delayed throttle response, almost like turbo lag. could it be that the engine sucked out all the air from the airbox and is waiting for it to refill?? i mean, you are still going kinda slow at the end of 1st gear, so maybe the air hasn't been replaced yet by new air coming in from the kidney grills. i know that makes NO SENSE at all since there is always air around us, but i'm just trying to come up with some reason

me too, me too ... i especially notice it when going from 1st to 2nd, when hitting the throttle hard

Yep that's it - its first to second when it can really hesitate - i did wonder as it seems to do it more when the fuel tank is under half full if the fuel was moving away from the pickup and fuel pressure was temporarily dropping. Its going to visit the dealer very soon as my oil level gauge seems to show different readings every day

I'll let you know what the dealer has to say

Cheers

James

[sixspeed]

Are people experiencing this on Ms, or on the other models? I can't say I've had this issue on mine, and it gets quite a few full-bore acceleration runs...

[Color]

sixspeed, I got it on my M . . . but now it has been like two weeks since last time.
Just delivered the car to first oil service and asked them to have a look at it. They will probably say they have not been able to reproduce the problem, but you never know.

[Color]

Well, to my surprise they DID find something that seems to be causing this problem.
Just got off the phone with the dealers and they did find an error code in the diagnostics that was related to the Lambda sensor.
This makes sense as the Lambda sensor controls the fuel/air mixture and an error here could lead to hesitation among other things Read up here

So they have ordered a new sensor which will be installed tomorrow. Let's hope that takes care of the problem.

[Z4 Forum AMW]

I have the same problem on my 2003 2.5 - anybody got any further with a fix - this appears to be a common problem so there must be a single fix??

[Color]

It seems my problem has been fixed by changing the faulty lambda sonde (One of the control sondes behind the catalysator).
I'ts a bit early to be 100% sure, but both the kangarooing on cold and hesitation seems to have gone.

[Z4 Forum AMW]

Do I dare ask how much this is likely to cost (mine is out of warranty!)

Can I do it myself or is it too tricky?

[flyboyaj]

My 2003 2.5i just started doing this after I drove her cross country and was forced to put different brands and varying grades (92 vs 93, and varying %'s of ethanol mix).

From the sounds of it this is what could be wrong:

Computer needs to be upgraded or "re-flashed"
Air filter bad
Fuel pump bad
Lambda Sensor

I'm going to drive her a bit more to pinpoint the circumstances of when this occurs then take it to dealer and I'll let ya'll know what's up.

[Z4 Forum AMW]

That would be great!

I have tried varying fuels and it doesn't make a lot of difference although I tried some injector cleaner in my tank and it made it less severe although it just returned!

There must be a definitive answer on this.........as many people experience it

[Color]

Do I dare ask how much this is likely to cost (mine is out of warranty!)

Can I do it myself or is it too tricky?

The first you would do is to check for error codes in the onboard computer, I think you need some special software to do that.
Or you could disassemble the exhaust system and check the function of each lambda sonde. But you have to be careful and know what you are doing or you can destroy the sonde by measuring in the wrong way.

I would recommend you leave it to the dealers.

[DAZ4]

It seems my problem has been fixed by changing the faulty lambda sonde (One of the control sondes behind the catalysator).
I'ts a bit early to be 100% sure, but both the kangarooing on cold and hesitation seems to have gone.

Interesting to hear of others with these problems. I've had a similar issue where I find when I haven't driven the car for a few days, whilst it's still warming up, the car judders as it pulls away. I thought it might be the clutch but it's been to the dealers a couple of times now and they can't find any problem with the clutch or electronics. Typically they can never reproduce the fault whilst they have it.

[Z4 Forum AMW]

Daz4 - do you mean clutch judder when first moving off or is it an actual hesitation when accelerating?

[DAZ4]

Daz4 - do you mean clutch judder when first moving off or is it an actual hesitation when accelerating?

Difficult to say as the pedal doesn't judder but the car doesn't move forward smoothly. I've never noticed it if I've not been changing gear.