2015 X3 M35d 78k stuttering under acceleration
Discussion
Either from a start or from low speeds, if accelerating (and more pronounced if accelerating harder) the car seems as if it is has fuel/spark/power etc. then for a split second, it doesn't, then it does again, then doesn't, as the speed increases under acceleration.
This is not aligned to any change in gears and it happens independent of any upshift in gear.
It isn't turbo lag, I'm well used to the car as I've had it since new.
The only similar thing I ever had on another car was a coil pack on a petrol 2007 Vauxhall Astra 1.8 auto. Swapping the coil pack over fixed that instantly. But this isn't exactly the same.
Currently on summer tyres (Pirelli P Zero run flats) in their last summer but still around 3mm. It happens on very dry surfaces on good roads so not sure how tyres could be an issue.
It "feels" like it is combustion based, almost as if there was enough fuel, then not enough or something was firing and then not firing etc.
Sorry the other thread was so vague. I just tried to get a late night post up for help and should have been more informative.
This is not aligned to any change in gears and it happens independent of any upshift in gear.
It isn't turbo lag, I'm well used to the car as I've had it since new.
The only similar thing I ever had on another car was a coil pack on a petrol 2007 Vauxhall Astra 1.8 auto. Swapping the coil pack over fixed that instantly. But this isn't exactly the same.
Currently on summer tyres (Pirelli P Zero run flats) in their last summer but still around 3mm. It happens on very dry surfaces on good roads so not sure how tyres could be an issue.
It "feels" like it is combustion based, almost as if there was enough fuel, then not enough or something was firing and then not firing etc.
Sorry the other thread was so vague. I just tried to get a late night post up for help and should have been more informative.
When did you last change the fuel filter? Have you had the EGR recall?
If it's still in spec for servicing I'd probably start with quick/ cheap/ free things you can do so try putting some high mileage injector cleaner through, have a look at the top of the injectors to see if the washers are leaking. After that you're probably into diagnostics territory to see if you can narrow it down to something specific or a specific cylinder. My 640d had a rough cold idle that I chased all over the place, turned out to be the intake manifold had about half an inch of oil/soot residue built up on it, doing no good at all for the airflow. That was noticeable from about 95k but it had basically only done long journeys so if yours has had more mixed use it might be a possibility at 75k.
If it's still in spec for servicing I'd probably start with quick/ cheap/ free things you can do so try putting some high mileage injector cleaner through, have a look at the top of the injectors to see if the washers are leaking. After that you're probably into diagnostics territory to see if you can narrow it down to something specific or a specific cylinder. My 640d had a rough cold idle that I chased all over the place, turned out to be the intake manifold had about half an inch of oil/soot residue built up on it, doing no good at all for the airflow. That was noticeable from about 95k but it had basically only done long journeys so if yours has had more mixed use it might be a possibility at 75k.
E63eeeeee... said:
When did you last change the fuel filter? Have you had the EGR recall?
If it's still in spec for servicing I'd probably start with quick/ cheap/ free things you can do so try putting some high mileage injector cleaner through, have a look at the top of the injectors to see if the washers are leaking. After that you're probably into diagnostics territory to see if you can narrow it down to something specific or a specific cylinder. My 640d had a rough cold idle that I chased all over the place, turned out to be the intake manifold had about half an inch of oil/soot residue built up on it, doing no good at all for the airflow. That was noticeable from about 95k but it had basically only done long journeys so if yours has had more mixed use it might be a possibility at 75k.
It gets serviced every 12 months at BMW and they do whatever is needed.If it's still in spec for servicing I'd probably start with quick/ cheap/ free things you can do so try putting some high mileage injector cleaner through, have a look at the top of the injectors to see if the washers are leaking. After that you're probably into diagnostics territory to see if you can narrow it down to something specific or a specific cylinder. My 640d had a rough cold idle that I chased all over the place, turned out to be the intake manifold had about half an inch of oil/soot residue built up on it, doing no good at all for the airflow. That was noticeable from about 95k but it had basically only done long journeys so if yours has had more mixed use it might be a possibility at 75k.
Usage has been mixed but regular decent 45 minute to 1 hour runs each week.
Sorry, not sure what "in spec for servicing" means ?
rottenegg said:
I had the same thing with my 2016 330d at 70k miles. It just had no power until the revs got quite high.
Turned out to be a faulty pre-cat O2 sensor after scanning it with ISTA. There was no drivetrain error on the dash.
ISTA is a must for any BMW really!
This has power but intermittently, a bit like ABS brakes have a grip on the wheel. On and off, quickly, then more power and less stuttering as the revs rise.Turned out to be a faulty pre-cat O2 sensor after scanning it with ISTA. There was no drivetrain error on the dash.
ISTA is a must for any BMW really!
I agree it needs to go for a review but I was trying to get a head start on what it might be.
to me this feels like a tyre issue... my wife was a 2017 F25 x30d and we had a similar issue.
under (heavy) acceleration between 30-70mph, i would notice a stutter which felt like a misfire. If you revved the engine when stationary - smooth as a diesel can be.
I started with an early fuel filter / air filter and service which made no difference. Tyres were ok, but one axle was more than the other (cant remember which one).
in the end i changed the tyres (BMW Star Marked) and instantly resolved!
It would be worth thinking about that as a possible solution
under (heavy) acceleration between 30-70mph, i would notice a stutter which felt like a misfire. If you revved the engine when stationary - smooth as a diesel can be.
I started with an early fuel filter / air filter and service which made no difference. Tyres were ok, but one axle was more than the other (cant remember which one).
in the end i changed the tyres (BMW Star Marked) and instantly resolved!
It would be worth thinking about that as a possible solution
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