[22andcounting]

I have had my new 520d Auto for 3000 miles now and have been experiencing a strange problem. On a steady throttle (even cruise) when going up an incline on the motorway at 1700 ish rpm there is a strange repeated hesitation/suble jerk feeling through the car. it feels for all the world as if the rear brakes are being applied on/off quickly. its a really subtle loss in power which lasts for a fraction of a second, then all ok, then again etc over and over. Spoke to the dealership they think it might be the gearbox retarding the torque for a change down and then deciding to keep in 8th and unretards the torque, then repeats the process.

Has anyone else experienced this effect?

[SilentHawk]

Had mine (520d M Sport auto) for 2 weeks, 1200 miles, and noticed almost immediately that it was doing this exact same thing. I also found that the cruise control would adjust slightly every time the jerking started - the car jerks for a bit, then cruise accelerates it slightly to move out of the "jerky zone", then settles down until shortly after it jerks again. I've also seen the MPG readout reflect the reactions of the cruise overriding the jerky parts. Really odd....

I've got it booked in to the dealer for Thursday and will mention the response your dealer gave. Will post back with the answer they come up with.

[martin mustang]

I noticed that on my new 520d M auto, on my journey from the dealer home, highway one, not since mind you no highways since, will check on it on my next highway trip. I read in one of the treads that the issue was now resolved.

[The Mewster]

Not something I've noticed.... Done around 10k miles in mine now.

[22andcounting]

Mine is now booked in at dealers for three days next week to try and fathom the problem, glad I am not alone - thought I was imagining it.

[Krill]

Originally Posted by 22andcounting

Mine is now booked in at dealers for three days next week to try and fathom the problem, glad I am not alone - thought I was imagining it.

My 520d M Sport auto does exactly the same thing. Please post an update after your visit to the dealer.

[Z4C_luvver]

I am also very glad someone else is experiencing the same problem, but annoyed that this problem has occured in the first place!

But here's the thing... mine is a manual!

I took it to the dealer who could find nothing (surprise surprise), and I too thought it was all to do with the cruise, but no, it does happen out of cruise (hmmm, must check if it occurs when the cruise is on standby...)

And as 22andcounting notes, it occurs mostly on inclines.

I'll print this out and stick it in front of the dealer, and will report back.

[22andcounting]

I have noticed it doesn't do it when in sport mode and 8th has been selected manually, only in full auto. Also in sport mode, when accelerating on full throttle the upshifts are very unrefined with very heavy torque retardation before the next gear is engaged. When I test drove the dealer car, they told me the 8speEd has the next gear up or down preselected depending on driving conditions so the changes are smooth and instant, mine is far from this, the dealer car was sublime, ultra smooth with imperceptible changes up and down

[SilentHawk]

Took mine in to the dealer today and one of the senior technicians came out on a test drive with me. Satisfyingly (for my sanity !) the car obligingly demonstrated the problem for us. It seemed to be at around 60-70mph, 1700-1800 rpm, going up a slight incline which I think 22andcounting noticed too.

Returned to the dealer and they put it onto the diagnostics - but no joy....nothing showed up. The tech guy said he thought it felt a bit like the effects normally seen when the engine goes into particulate burn, but the diagnostics showed this hadn't occurred for over 500km.

So, they've raised a PUMA (is that the right phrase ???) and will wait to see what comes back. I did mention there were a few of us with this issue, so hopefully BMW will see the trend.

Will let you know what response we get.

[22andcounting]

@silent hawk, thanks for the update, I had mine on the diagnostics last week and also no errors found, gonna print off this thread for the dealer next week, hope BMW find a resolution. I did the throttle reset procedure last week and I thought it had cured it, it certainly drove better in general much more likely to being the correct gear and change down when required, but it soon resurfaced. I had heard some similar issues on the e60 and it was tracked down to the exhaust gas recirculation settings, a reprogram cured it, not sure what egr is but i understand it reduces emissions by reburning the exhaust gas which might explain the apparent loss in power?

[Krill]

Is there any news on this issue yet? Thanks guys!

[slimer]

Second car in the house, Audi A4 '06 2.0 TDI has the same problem.
And when it is cold, below 0 degrees it does not accur, but as we approach spring and summer it comes back.
I have had the car to several different Audi dealers and they never found out what the problem is. ECU shows no error.

I know this is BMW forum but just telling that several car makers/engines have these problems.

When it starts to jerk, just a small lpush on the gaspedal or release and it stops.
This on a manual car.

[Sinus]

This could be a problem with the Diesel Particulate Filter and a pressuresensor not working good together. The filter starts regenerating way to often and that causes a small lost of power. In the Netherlands some people had the same problem, BMW changed the DPF and a sensor and the jerking was gone.

[22andcounting]

My car is now with the dealership. We did a test drive this morning and after a few miles it started its little party trick, very subtley at first but getting progressively worse as the miles clocked up. The engineer thinks its a software issue and is going to hook it up to their data collection pc and drive ot for a few miles to get extended data to send to BMW. The dealership have loaned me a 520d msport with the sport auto option (lovely lovely car) and guess what - yep this does it too :-)))

I have two problems now, one the trembling transmission and two wish I had gone for the msport and DEFINATELY wish I had got the sport-auto option, dont ever order this car without it, the SPORT setting is sublime - throttle, steering and transmission totally connected, crisp and progressive - think I am gonna keep this loaner ;-))

[SilentHawk]

Good luck 22andcounting - mine's booked in next week for two days but I'm only getting a 1-series courtesy car !

I've also noticed that it does its thing even when put into manual mode, and at all road speeds, providing the load on the engine is at a certain level (either by driving up an incline, or by passenger load) and the revs are at around 1600-1800. I've had it doing it at 35mph, 50mph, 70mph....

[northernmonkey]

Is everyone seeing this in a 520d?

Just wondered.

Can't say I've ever noticed it in my F11 530d (MSport with sports auto) I do a lot of motorway miles. Is it only when cruising up inclines? Have to check next time I'm out.

[22andcounting]

Got a puma raised for my car too, everyone who has the problem needs to get into their dealership and get puma's raised for their cars too, the more cars known to have the fault the quicker BMW will try and sort it. I've heard of the dpf issue being thrown at lots of problems, I am not convinced, it's just happens too ften, mine will 'tremble' on every hill twist Sheffield and Slough. I have noticed it happens in. Series of three like hesitations ie de de de, then goes away the again then a de de de again

[22andcounting]

@silent hawk, yep agree, 1600-1800rpm is the trouble spot, steady throttle, under load, had it in different gears

[Darkeeboy]

Ditto on my 520 manual. They put it down to dodgy fuel (Shell!) but its still jerky around 1800rpm on gentle acceleration.. Gonna monitor this thread for any positive outcomes.

[northernmonkey]

Originally Posted by northernmonkey

Is everyone seeing this in a 520d?

Hmm just noticed thread title.....back of the class northernmonkey!

[Z4C_luvver]

....and this is where forums shine.

Here we are, a group of people who, with our collective experiences and abilities to isolate these issues, can now collectively present our case to BMW and obtain an outcome that would otherwise take exponentially longer or at worst never be acheived.

Go forums, go us!

[HighlandPete]

Have any of the garages suggested it could be EGR strategy? With ever increased EGR ratios, are we seeing the 'tipping' point on some engines/fuels?

It is known that faulty EGR valves can cause this sort of stumble, but if it is common on a particular engine model, may be worth asking the question of the BMW technical guys.

Remember the EGR strategy is different on a cold engine, so if that factors in, (smoother when cold) it could be a clue to where the issue lay.

HighlandPete