W211 E320 V6 (2009) - Juddering Under Light Acceleration (1250/1750 RPM)

[DanMorgan]

Hi All,

I have a relatively odd problem that I can't decide if its engine or transmission related.

Under light acceleration approx 1250/1750 RPM (i.e. maintaining speed going up a slight incline), the car would judder. I notice the judder mostly when the car is warm and definitely more in 2nd gear than other gears.

However, under heavier acceleration, there doesn't seem to be any juddering whatsoever. The car pulls like a train and the gear changes feel smooth.

Any advice would be greatly appreciated - The car in question has 165K miles on the clock and is also running a Brabus D6. The most recent work that was carried out was a new seal on one of the injectors but I doubt its anything to do with that.

Thanks

 

[design guru]

I would start by checking the propshaft coupling, although it would be consistent juddering no matter what speed you do, but they do cause juddering when they begin to wear.

 

[DanMorgan]

I'll get this checked out - I plan to do the ATF in a few weeks time to rule that out too.

I have a STAR machine, do you (or anyone else) know if I can run some tests to rule out a few things?

 

[m80]

It could be worth checking the smooth running of the engine, to attempt to rule out an injector issue.

Might be worth looking in to the turbo actuator, to be sure it's not sticking. That can be actuated on Star.

EGR same.

Check suspension bushes for free play.

A favourite check is the engine mounts, might as well check the gearbox mount as well.

 

[DanMorgan]

It could be worth checking the smooth running of the engine, to attempt to rule out an injector issue.

Might be worth looking in to the turbo actuator, to be sure it's not sticking. That can be actuated on Star.

EGR same.

Check suspension bushes for free play.

A favourite check is the engine mounts, might as well check the gearbox mount as well.

Great suggestions - I'll look into this with STAR

 

[TeddyRuxpin]

I have the same thing, sometimes. I find it’s worse when in hotter weather or if the car’s quite hot. E350 231bhp version with 7G box (not 7G+). Remember the fluid is supposed to be changed pretty often in these boxes.

It doesn’t happen all the time, in fact most of the time it doesn’t happen.

I’ve had the Brabus D6 box on up until recently too, and it did the same with/without that.

I already have new engine and gearbox mounts and don’t “believe” I have a vacuum leak.

I’ve also cleaned the EGR several times, no issues there.

I’m booked in for a gearbox service this Friday - I’ll let you know if it resolves the issue. Apparently 1500rpm is around when the torque converter stops slipping and so it could well be gearbox related.

It could also be the turbo actuator sticking and some people will scare you and say you need a new torque converter or gearbox. Others will also say it’s normal (from reading several threads on this). I was really sure that it was a vacuum leak but I don’t believe it to be the case. I have not paid for a vacuum leak test to be 100% sure however. I’ll probably do that if I get it again after the gearbox service, as well as check out the turbo actuator.

Most of the time people have issues on hard acceleration but light throttle is the weird thing here.

 

[MikeInWimbledon]

Probably a dumb question, but have you checked plugs and tried a fuel line cleaner?

It’s not an issue I’ve ever seen on MB V8’s but it’s infuriatingly endemic in BMW petrol 6’s.

BTW: And what kind of mileage has your car done?

 

[TeddyRuxpin]

OP's done 165k mine's done 175k. Been the same for as long as I can remember (I bought the car at ~125k). But it's intermittent so it's difficult to remember when I first noticed it.

I ran Shell V-power exclusively until the fuel price crisis, now I run cheaper diesel with Redex every single fill up

I'm more inclined to believe it's a gearbox/torque converter servicing issue, that or the turbo (again, ~1500rpm is when it kicks in).

When googling, I've read that the issue has resolved itself with a gearbox service - but I can't remember if that was on a MB or not.

In any case I'm personally due a gearbox service anyway, so we'll see if it makes any difference or not! Given the cold weather, the car isn't really exhibiting this issue at the moment anyway.

 

[DanMorgan]

Hi both,

When the weather cheers up a bit, i'll get it on STAR to check @TeddyRuxpin & @m80 suggestions.

--

I always tend to run an injector cleaner every other full tank and the car fires up on the button, so wouldn't have though the plugs would be at fault.

 

[TeddyRuxpin]

Mine doesn't produce any codes btw!

 

[BlackC55]

A light judder could be so many things. I would get an experianced MB tech to drive it to see what there opinion is before doing anything.

 

[MikeInWimbledon]

OP's done 165k mine's done 175k. Been the same for as long as I can remember (I bought the car at ~125k). But it's intermittent so it's difficult to remember when I first noticed it.

I ran Shell V-power exclusively until the fuel price crisis, now I run cheaper diesel with Redex every single fill up

I'm more inclined to believe it's a gearbox/torque converter servicing issue, that or the turbo (again, ~1500rpm is when it kicks in).

When googling, I've read that the issue has resolved itself with a gearbox service - but I can't remember if that was on a MB or not.

In any case I'm personally due a gearbox service anyway, so we'll see if it makes any difference or not! Given the cold weather, the car isn't really exhibiting this issue at the moment anyway.

You’re right.

 

[W1ghty]

 

[350cls]

View attachment 134094

Brilliant

 

[W1ghty]

Brilliant

Knicked it off @Larkone

 

[Watchcame430]

Hi all, I have just a few days ago bought a 2006 E320 that has this symptom only when I lift off after accelerating.
Does that change anyone’s opinion on what it might be?

 

[BlackC55]

Look at the engine mounts

 

[Watchcame430]

Look at the engine mounts

Will do, thanks.
Is this something you have seen on lifting from acceleration? It does feel gearbox related somehow but will get them checked over.

 

[BlackC55]

They are difficult to check. You have to feel if they are worn. Generally most don't notice when they are. Just get an experienced MB tech to drive it.

 

[Watchcame430]

They are difficult to check. You have to feel if they are worn. Generally most don't notice when they are. Just get an experienced MB tech to drive it.

Thank you. Corrected the typo above so hopefully makes sense now.

I have been looking for someone local to check it out. As you say getting someone experienced makes sense.

Only bought it a week ago and really would like to get it checked over. ABS light popped on now and had a puncture 2 days after buying it.