BMW Z4M S54 - slight hesitation/stutter when you press the accelerator from idle.

[Adamw]

As per title, I have a slight hesitation/stutter when you press the accelerator from idle.
Can only describe as a ‘tiny cough/miss’.

I’ve had this since I’ve owned the car (last Oct) but thought maybe normal behaviour of s54 as no other warning lights or misfires through the rev range and it pulls very strong.

I drove a mates e46 m3 and he drove mine and he picked up on this too and his car doesn’t do this.

After a quick google search a few suggestions came up:
* Dirty or aging MAF sensor
* Throttle actuator synchronization
* Coil packs or spark plugs starting to weaken
* Intake air leaks (perished rubber / vacuum leaks)

It does this regardless of the engine temp & as mentioned it’s just off idle / low revs.
There’s no engine light / misfire or any other signs of issues.

I wondered if anyone had experienced anything similar ?

 

[bigwinn]

Yeah I have

I started off by replacing the two throttle position sensors- one at the front and one at the rear of the fuel rail

That made a difference and I checked the throttle linkages for smooth operation

However a few months later the stutter returned and threw a code for throttle actuator stiffness

I did a thread on the throttle actuator rebuild as I needed to remove it and had it sent to a chap in Spain who did a proper job

It’s not come back yet

 

[DevonPaul]

Our has always done it, especially if you press the pedal hard.

Replacing the TPS helped for a bit, but it came back. Seems fine if you 'pre-load- the slack on the throttle.

 

[Mr Tidy]

Mine has been prone to that as well.

 

[MrPT]

There's a big ol' thread on it here.

Are you able to reset the throttle adaptations (e.g. using INPA)? Might not be a permanent fix, but could point you towards one. If you have INPA you can also run a throttle actuation test (although it should be fine/healthy if no errors are being thrown).

 

[Adamw]

Thanks all for responses so far.
Sounds like a bit of a common problem then.

It doesn’t affect any other elements of driving but is annoying.
Just wondered if there was a known fix but sounds like it could be a number of things.

I might ask my indi to look next time it’s in, or
otherwise I am contemplating a csl style airbox so wonder if the map would cure

 

[AndyBeech]

Yeah, think I've had the same since day one. Stab of the throttle at idle sometimes makes it splutter though not checked that since remapped actually. Also get the occasional rev drop when coming back down to idle, like it drops a bit below normal idle revs before settling.

Pretty much everything's been changed that might make a difference, apart from the throttle actuator. Since there's never been any codes and it doesn't make a difference to actual driving or driveability I gave up looking for a solution years ago and just ignore it now.
It's been mapped and carbon airbox as well with no difference so who knows!

I wouldn't get hung up on it tbh. Different ECU(DME) to M3's which probably has something / some part to play in it as you never hear about it on those. Just for info, it's done it since I brought it on 60k miles, now on 117k and it's never got any worse.

I could list all the things I've had changed so you could 'rule' them out, but impossible to know what didn't cure it on mine might cure it on yours hence I'd suggest not worrying about it and put it down as a quirk unless it affects actual driveability/throws codes like bigwinn. Without a code you're kinda peeing in the wind.