Z4-forum.com

Hi all,

From what I read the Z4M is no stranger to having a few noises and quirks to it, so just wanted to check if anyone had the same 'symptoms' as my M Coupe. I've searched for similar things on the forum but can't find any.

#1 problem is if I put the throttle down too aggressively at low revs my engine RPM will often drop first, stutter and then rev up the range. If I increase the throttle gently then it's fine and goes straight up. Normal... or bad sensor/Vanos?

The second one is the clutch/gearbox. If I'm in first gear and press the clutch pedal there's a distinct noise as the clutch disengages from the gearbox... again, is this normal?

Sorry for the noob questions, just never had these issues with my Cayman S or any other car for that matter. I'm happy to live with it though if it's just typical of the M.

Thanks all

#1 Sounds like the s54 'hestitation issue' that is quite common.
There is a long thread about it (viewtopic.php?f=9&t=39891&hilit=hesitation+issue).
The real root cause is not completely clear (AFAIK) but a lot owners including myself have good results by thoroughly cleaning the IACV (air bypass valve) even when this turns out not be very dirty it usually is still beneficial to clean it.

#2 Does not sound familiar to me.

The throttle seems like you have throttle position sensor probs,or sometimes MAF can cause a drop out under light throttle.

Noises on the transmission are common,they are a bit agricultural.

Depends what the noise is it... They can make a bearing noise as the first motion shaft bearings and idler bearings are generally noisy.. There is also a "clump" noise as the clutch plate clamps the flywheel when the pedal is released...

Thanks both, never found that Engine Hesitation thread - sounds like what I have. It's due in for a service soon so I'll see if new plugs, coils etc makes a difference first.

With regards to the clutch, the 'clump' noise you speak about happens for example when the car is in first gear and I then push the clutch to put the car in neutral.

You don't need new coils, give the maf and the icv a clean. If that doesn't work there's two tps sensors, from memory about 30 pounds from bmw. Buy one and try it in both positions, I think the front one is normally the dodgy one?

Ref gearbox, sounds fine to me if you want to improve it remove the cdv, makes it feel like a normal clutch/box.

Remember you have more of a drivetrain on a bmw than a porsche so there's a lot more backlash/slack which you will just get used too.

RedUn wrote: ↑Wed Jun 07, 2017 8:42 pm Ref gearbox, sounds fine to me if you want to improve it remove the cdv, makes it feel like a normal clutch/box.

Is it really that noticeable on the M? I've been hesitant to remove mine because when driving hard and accidentally dumping the clutch with poor timing I'm concerned that shock to the drivetrain from the high powered engine could cause damage?

I thought it was quite noticeable, feels much more linear and responsive to me. I suppose if you keep dropping the clutch then over time it won't be the best but the box and diff are strong, people are running a lot of power through the same setup

As did,the hesitation is probably down to the idle control valve being dirty/clogged with deposits through time.amd/or throttle position sensor s??

Try these ,as it fixed mine from doing the same,within the last year

Thanks for all the info guys, I will look to clean the ICV and go from there!

this is a noisey car.

it ticks , clunks, and is full of mechanical noises.....