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Discussion Starter #1 (Edited)
2004 E46 330Cd Boost Problems - FIXED!

Hey all,

So I've not driven the car much the last few months because of a lower back problem I have, but it seems to have now developed a bit of a problem with the turbo not boosting properly.

It's completely random. Sometimes it will boost fine, sometimes not at all, sometimes it will boost in the 3-4k rpm range.

Plugged the laptop in and got this code (in addition to a few expected... swirlflap removal and glow plugs):

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

So cleared codes, took it for another spin and then got:

4191 4191 (1252) air charge pressure controller, Ansteuerung
and
3F57 3F57 (1272) air charge pressure controller

After some googling, I suppose the first thing to try would be to replace the MAP sensor, then check actuator(electronic) / turbo?

Any words of wisdom would be appreciated.

Cheers!

UPDATE BELOW FOR MY FIX
 

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Sounds like the turbo actuator, they can stick. You'll need some grease to free it up, I dunno if it's a pressure one or electric, if electric you might not be able to manually move it as it'll be geared but the pressure ones you can get a good grip and wiggle them free.
If they are like the vag ones, they have veins inside the turbo that can get stuck with soot, I think they only way of clearing that would be to pull it, split it, clean it and pop it back in.
Not a hard job but it's long and tedious, especially on a drive.
Map sensor, usually a false reading. You can unplug it while running and take for a drive to see if makes a difference.
 

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Is this one EU3 with vacuum actuator or EU4 with electric turbo actuator? You'll see if there's a vacuum bell or electric actuator at the side of turbo. Then when starting the engine check if the rod is pulling guide vanes closed.
 

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Discussion Starter #4
Thanks for the replies... and it is an electric actuator. Have put a new genuine MAP sensor in, but sadly no luck with that.

The actuator doesn't move when starting the engine, so looks like that's the problem.

What's the easier way to get the turbo and actuator out? From the top or remove the under-tray and take it out the bottom? I'm going to have to get my bro to do this as i have a bad back atm.

Cheers!
 

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From an old post:

"Underneath, remove engine mount and jack up the engine and remove the
steering column obviously the covers,exhaust etc"

Should be about 2-3 hours for removal and 2 more for installation.

With the vein turbo's, if not blown you can split them, clean up all the gunk and soot inside and test to see if the veins move more freely.
Could also be the actuator that's at fault.
 

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Discussion Starter #6 (Edited)
UPDATE:

So just thought I'd post an update on my boost problems in case it helps anyone else.

As my car hasn't been used much with my back problems, this problem seems to have come from lack of use. At the same time my bro's turbo blew up quite spectacularly in his Jetta, so he has been using my car.

Checked the actuator and it wasn't moving at all on engine startup.

So have been using WD40 & duck oil and spraying all the moving parts on the actuator. Low and behold after few days of using the car and more spraying, everything is running and boosting as it should! :D :D :D

Cleared codes and confirmed after running it.... no codes! :D

Hopefully this fairly simple fix might help someone else, or even a preventative thing to do even if yours is running fine.
 
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