BLB 2.0, boost pressure regulation limit exceeded. trying to clean turbo advice.


Registered User
Mar 23, 2014
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Bought a 05 A4 a few weeks ago, kinda annoyed i didn't do any research on the BLB engine before buying but alas this is where im at.

It was perfect the first two weeks, then every now and again it would go into limp mode... no big deal turn off and on the ignition and go again.

then last week it went into limp mode 3 times within 20 min and the check engine light came on, I put it on snap-on solus and got 3 fault codes, the 4 glow plugs, some electrical fault (never have any trouble starting it), engine mount (is a bit of a shudder in neutral sometimes), and boost pressure regulation: limit exceeded.
i didn't get time to address the issues with work so just drove conservatively till i got a day off to look into the faults, then last night it just went into limp mode and will not come out of it, and the check engine light appeared again!

from any research iv done the main cause of the last code seems to be stuck vains on the turbo, i got underneath the car today and while the actuator on the turbo is moving, it dose require some force to move so im convinced the turbo veins is gunked up!

so first off, can i use the MR muscle oven cleaner trick? as in spray it into the exhaust housing or egr valve opening to free it up? or how hard is it to take the Turbo off and split the housing to get right into the gunk if its indeed there(Im a bit afraid of snaping some bolts in the process)? do i take the turbo off from the top or bottom, or do i need to remove the whole front of the car as iv seen some people do?

or is there any other suggestions as to what my be causing the fault?

i know this is my first post but trust me i searched on lots of sites and cannot find any definate answers for a BLB engine, or anywhere detailing how to Remove the Turbo.

Thanks in Advance


Registered User
Oct 9, 2013
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I did strip a scrap merc vnt/vgt turbo out of curiosity, and whilst it was a fiddly little sod its wasnt to hard.
Have you tried some of the tricks you can do to clean inlet pipework etc? may work on the turbo vanes as well?
Cant think what its called but its an aerosol and about 20 quid you run motor and squirt it into intake pipe at a fast idle
This is one but not the one I was thinking of! How to use Seafoam to clean up your engine | eHow


Registered User
May 14, 2012
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just search " sticky for turbo cleaning" all info and pictures are in that thread