Z4M S54 Engine Hesitation Solution

B

bertman

Member
Hi Everyone

I bought a Z4M Coupe, 3 or so weeks ago and I've been having some dramas. It's currently in getting a broken engine mount bolt replaced (they'll only replace the affected bolt) and I've asked them to look at the engine hesitation as well.

The hesitation is the same as others have described where it "misses" when you tap the accelerator. It's been there since I originally test drove the car and it was a condition of sale that they fix it prior to delivery. The sales guy said the mechanics fixed it by running the engine at max rpm for 10 mins to clean out carbon deposits. It did seem better for about a day but then it came back. I've run nothing but 98ron fuel through it since taking delivery, using all 3 major brands. I noticed on one brand in particular it was much worse but the hesitation was present with all 3.

I've been scouring the forums trying to find a definitive solution to the problem without success. It seems that most people have put it down to fuel, but no one can explain why the problem happens with some cars and not others.

Has anyone successfully fixed this problem long term? I'd love to hear your comments

bertman.
 
I had that problem with my 2007 M Roadster and my dealer traced the problem which is not uncommon to a fuel injector which they suspected from the outset. Fuel injector was replaced and problem was fixed. I'm sure there are other possible reasons for a problem like that.
 
BMW just called and said they replaced 1 of the coil packs which was arcing and all the plugs. This has helped but hasn't solved the problem. I'm going to go in and check it out. They're making out this is just how the cars are....
 
Just collected it is running allot better but he made it clear it's not perfect. They also did an ECU upgrade which apparently hadn't been done since new. I'm not sure what effect this will have but the sport mode is now much more livable and I've noticed more exhaust popping. Interesting. The hesitation is still there but it has the worst the 3 types of 98ron fuel in it at the moment so hopefully I can fill with the best 98ron tomorrow and see if it improves further.

The head mechanic met with me to discuss and some other well dressed employee was included in the conversation but didn't introduce himself. I assume he was witnessing the conversation because the mech basically said they wouldn't be doing any more work to resolve the problem, because they have another car there that does the same thing. Apparently in their mind this proves the problem isn't a problem, but a quirk. That pisses me off more than anything but I'll see how the car goes with the better fuel before going to war with them.
 
bertman said:
The sales guy said the mechanics fixed it by running the engine at max rpm for 10 mins to clean out carbon deposits.
Click to expand...
Won't be taking my car there any time soon.

Hope you get it sorted.
 
Rialas said:
bertman said:
The sales guy said the mechanics fixed it by running the engine at max rpm for 10 mins to clean out carbon deposits.
Click to expand...
Won't be taking my car there any time soon.
Click to expand...


Unbelievable. Run the engine a max rpm for 10 mins.... How do they do that??? Leave the thing stationary and just rev the s**t out of it.... Shocked.
 
Yeah I wasn't a bit shocked as well. I'm not sure if this is a common thing they do but I mentioned it to two of the mechanics there and neither indicated it was an unusual thing to do
 
Having read the threads on this problem and being blessed with a car that has only the slight occasional hesitation in traffic I suspect that there won't be a definative 'fix' for this.

I think it is probably a 'quirk' of the car that a blip of the throttle catches out the ECU/injectors etc and causes a slight splutter. Any defect with a plug, coil. sensor etc my cause the problem to become worse and in some instances really spoil the drivability of the car. Driving the car hard regularly seems to keep my car running fine and I always give it a regular 'thrash' when oil is up to temp. I guess that's the sensible equivalent of ten minutes at max revs :cry: to clear the carbon deposits out!
 
I still haven't been able to cure this on mine either and it feels like a dampened throttle and lag between the engine revs and the throttle input once the initial stumble has cleared, the coils seemed ok with basic multimeter testing but I havent been able to run any tests on the throttle potentiometers and throttle position sensor as I dont have a diagnostic computer.

I wonder if the valve clearances could even cause this problem as an AUC BMW car I have no paperwork showing any previous adjustments have been carried out at insp 1.

Its annoying that it isnt working like I think it should :headbang:
 
I had this problem. It was always there in a lesser extent from when I bought the car, but got significantly worse after my GruppeM (noticeable when driving) So figured my man handling of my MAF whilst fitting the Induction may have been the cause. Bought some MAF cleaner (not cheap!) and that made a difference. But still not as it was. So run BP Ultimate for the next 3 tanks (having put in mainly V-Power) and its back to how it was. Ie only evident whilst blipping the throttle whilst stationary.

So I reckon it is just a characteristic of these engines, but one that can be made worse by other issues - ie dirty MAF etc? I'm wondering if the dirty maf caused a build up somewhere that was cleared out by the BP fuel? Or maybe it would have been ok after a few hundred miles of driving on any fuel? Not sure. I'm going to try running back on Shell and see if it comes back?
 
Has anybody tried cleaning the fine mesh filter just before the MAF? If this gets blocked iT can make the air flow over the maf do strange things fooling the maf
 
It could be the MAF but I'm certain I've read a post by a guy with the CSL intake and tune (no MAF) having this problem....
 
I have had a new maf under warranty - made a 10-15% improvement in fuel consumption but didn't help this issue sadly.


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