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Simon82

That dreaded 320d Turbo VNT problem!

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New to this forum so hi all! I've put an introductory post up as well..

So just a bit of background.. I bought my 320d a few weeks ago and everything was ok.. so I thought, I'm not a noob when it comes to buying a car but I probably rushed this one a bit because it was a good price (wonder why?)

After a few days I gave it some beans up the gears to 6th and noticed it stopped boosting after cruising around 75-80leptons. I'd done my research before buying so figured it was limp home mode because something wasn't right.

Checked out the error codes on INPA and got:

4191 (1252) air charge pressure controller, Ansteuerung
P1252 Boost Pressure Positioner Circuit Low

4521 4521 (1296) air charge control, Regelabweichung

I figured from research that it was a case of actuator fault or sticky vanes, or possibly map sensor.

On investigation when I turn the ignition on and watch the turbo actuator (electronic actuator) it hardly moves and I can hear it clicking as if it wants to move. I've removed the VNT arm from the actuator and turned the ignition on and the actuator does a full motion check and returns to the default position so the electronic actuator seems to be fine. When manually trying to move the VNT arm it can't budge it at all!

What I've done so far to relieve it:

  • 2 Bottles of Forte Diesel Turbo cleaner in a full tank.
  • 1 Bottle (750ml) of Revive Turbo Cleaner & Power Restorer
  • Mr Muscle through a tube into the EGR outlet down into the turbo

The arm still stuck solid :mad:

When I ran the revive solution through it cleaned a hell of a lot of crap out too!

I've been trawling through BMW forums and not found anything like the problem I've got? I can't see as anything mechanical would have broken inside as I can spin the turbine with my fingers and it still boosts when not in limp home mode?

any ideas welcome :thumbsup:

Thanks

Simon

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Thanks Greg

Really was hoping there's a way without having to strip the turbo off, looks like a serious pita to do.

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They use the same turbos as the VAG PD diesel engines and the issues were worse on them, I guess its down to the electronic vs vacuum operated actuator? Once the turbo is off they are not difficult to split and clean up. If I can do it anyone can do it! :thumbup: A few nuts, some careful handling and a bit of time and it can be sorted. Taking it off the car however I wouldnt know!

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So, E46-wise, does this only affect the M47 engines? Could it be a potential issue on M57s?

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They aren't bad to remove, just take your time, you'll be fine!

Can they be removed from the engine bay or do you have to shuffle around underneath?

So, E46-wise, does this only affect the M47 engines? Could it be a potential issue on M57s?

It seems when BMW made the decision to 'upgrade' the range of engines with the new swirl flap design etc.. they seemed to switch the garrett units as well from the vacuum operated to electronic, both have their problems - a damaged vacuum pipe can be a pain but possibly an easy fix, whereas a broken electronic actuator and BMW will tell you it's a whole new turbo needed :rolleyes:

Needless to say, any of the engines with the VNT/VGT turbos can be affected by the build up of oil/soot, including VAG.

http://www.bmwforums.info/general-guides-how-tos/1030-bmw-diesel-turbo-common-faults-m47-m47n-m57-m57n.html

Si

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Posted this in General help as well as I'm looking for a replacement turbo but..

Can anyone with an electronic actuator turbo (or someone that's removed one) confirm if there's an adjustable endstop on the outer pivot arm on the turbo housing? Reason I ask is that the actuator arm on mine refuses to travel even a mm (arm off the actuator servo). So I'm wondering if the endstop has loosened and worked itself all the way out to prevent the pivot arm moving. I'm still driving the car (slowly) & on 12hr day shifts so can't get to have a decent look at it until next week..

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQhqiJKjYUxb1WDwGS1hAmze691uSIL2xNxzh7ZBuzu9LcCwNecLg

(works firewall stops me from posting direct images)

Thanks

Si

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