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Discussion Starter #1
My 520d runs smoothly, but lacks power as if the turbo isn't doing much. There are no warning lights on and you can freely rev the car above 4000rpm, so I don't think it's going into limp-home.

I have tried unplugging the MAF, and it drives exactly the same. I've tried plugging in my general diagnostic tool, but it says there are no fault codes logged.

Any likely failures?
 

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Possibly the MAP sensor at the rear of the inlet manifold but have also heard the turbo actuator failing on the E9*s 320ds :confused

Any chance you can borrow a MAP sensor or get live data logged?

If you've disconnected MAF and run car without any errors flagging up would have to say your diag tool isn't up to the job
and you need a BMW specific diagnostic tool :thumbsup
 

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Would be a good idea to get the BMW fault codes read also, then have them cleared and re-read later to rid the system of any old codes from when you were unplugging items. :thumbsup
 

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Discussion Starter #4
Yes, I have a Delphi diagnostic machine. It does most manufacturer specific stuff, but for some reason it doesn't let me see the faults in detail on this car. I know there are 4 faults logged under the DDE heading, but I can't get in to see them!

When I do live data, the manifold pressure doesn't seem to move (even when revved). It hovers between 97 and 103 (kPa I assume). Would this reading be taken directly from the MAP, and suggest it has failed?
 

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Discussion Starter #6
Sorry don't know required MP values but can compare with live data from my E46 320d tomorrow if that helps?
That would be very helpfull, thanks.
Am I right in thinking this value must come directly from the MAP, or could it be derived form other values?

If it's anything like a Toyota D4D that I was playing with the other day, that rests at atmosphere (100 kPa) and rises to about 200 kPa (a range of about 14psi). I expected the 520d to be about the same.
 

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Fraid you'll have ask someone more technically savvy than myself for that info :embarrassed I'm ok with the basics but thats well beyond
my tech remit and I'm slowly drowning :hihi

Will post up live data early evening and hopefully someone in the meantime willbe able to answer your question :thumbsup
 

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Discussion Starter #8
Sorry, I think it is in 'limp home mode'. When I was driving it yesterday, it would go over 4000 revs when driving, but it now doesn't when you rev it on the spot. I assume it ignores MAP output when in this mode (i.e not using the turbo).
 

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If the pressure in the manifold isn't increasing when revving, then I would agree with Simon...you may have a faulty MAP sensor.
 

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Discussion Starter #10
Just had the fault codes read. There were quite a few in the system (as if someone had been unplugging things in the past) so I deleted them, then ran the car and checked again.

Only two remain:
1) 4232 Glow Plug Cyl 3 - Activation Interrupted.
2) 4530 Boost Pressure Actuator - Regulation Pressure too Low

Does this suggest the MAP still?
 

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Boost pressure actuator built into turbo...not cheap :frown Hope it's not blown, check the hoses around it.
Sadly agree with Neal, there a place in Midlands fixing the actuators, iirc BMW just replace the Turbo and actuator = mega bucks :frown

found them, quote taken from this thread .........
I used these guys to fix the actuator on my Mondeo diesel which uses the same actuator, made by hella and you get a 2 year warranty. Send them the unit and they repair and return the same day. From memory it cost be £150, much cheaper than a new turbo !! :D

http://www.ecutesting.com/bmw_3_series_turbo_atuator_fau.html
 

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Discussion Starter #13
Thanks for the bad news. I was hoping for a £50 sensor! I don't have the ticking/rattle noise that other people have reported, or does that come later?

NeilP - Which hoses go to the actuator? I was under the impression it was an all-electonic item?
 

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Discussion Starter #14
Thanks for the bad news. I was hoping for a £50 sensor! I don't have the ticking/rattle noise that other people have reported, or does that come later?

NeilP - Which hoses go to the actuator? I was under the impression it was an all-electonic item?
UPDATE: Just put my VIN into realoem and it shows that I have a normal vacuum-opperated turbo actuator, not an electronic one. Does the vacuum unit fail, or is it more likely to be a stuck rod or split vacuum hose?
 

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UPDATE: Just put my VIN into realoem and it shows that I have a normal vacuum-opperated turbo actuator, not an electronic one. Does the vacuum unit fail, or is it more likely to be a stuck rod or split vacuum hose?
You sure ? :confused even the E46 320d M47N engine had electronic actuators fitted post Sep '03 never mind your M47N2 engine.
I can't see BMW reverting back to vacuum controlled units 4 years later, you can visually check though as above the turbo
there will be some sort of plastic vacuum reservoir and the Turbo Pressure Converter will also be visible. :thumbsup
 

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Discussion Starter #16
You sure ? :confused even the E46 320d M47N engine had electronic actuators fitted post Sep '03 never mind your M47N2 engine.
I can't see BMW reverting back to vacuum controlled units 4 years later, you can visually check though as above the turbo
there will be some sort of plastic vacuum reservoir and the Turbo Pressure Converter will also be visible. :thumbsup
You're right. I've just looked and where I would expect to see the old style vacuum opperated actuator, there's a rectangular box (looks like there's a multiplug underneath). On RealOEM it comes up as an M47N2, as you thought, but then only showes the old-type turbo....strange!

Is there anything I can check on this (hoses/pipes etc.)?
 

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You're right. I've just looked and where I would expect to see the old style vacuum opperated actuator, there's a rectangular box (looks like there's a multiplug underneath). On RealOEM it comes up as an M47N2, as you thought, but then only showes the old-type turbo....strange!

Is there anything I can check on this (hoses/pipes etc.)?
Must be a glitch with RealOEM and your vin. no.! if you simply access 2007 320d (M47N2) on RealOEM the listed turbo isn't vac controlled.

Only thing I can think to check is the actuator rod for movement but saying that if its still in limp limp mode it wont move :mad

Have you contacted ECU Testing they may be able to shed some further light on the issue? :thumbsup
 

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Discussion Starter #18
Must be a glitch with RealOEM and your vin. no.! if you simply access 2007 320d (M47N2) on RealOEM the listed turbo isn't vac controlled.

Only thing I can think to check is the actuator rod for movement but saying that if its still in limp limp mode it wont move :mad

Have you contacted ECU Testing they may be able to shed some further light on the issue? :thumbsup
When I read the fault codes, I cleared all the faults and the car came out of limp mode. So far only codes 4232 and 4530 have come back, but the car still revs OK.

I've just taken a video of the actuator rod and revved the car up, the rod seems to move freely enough. I'll post on youtube in a moment and let you have a look. Thanks.
 

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Sadly the vids a bit dark but the actuator arm certainly moves :confused

Can only think you try and get a hold of the MAP sensor from another BMW, its the same part for the M47N engine too, see LINK,
hopefully that will help confirm which part is fubarred ? :thumbsup
 
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