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Discussion Starter #1
I removed the Turbo to test it because it was full of oil. I found out later that this was normal on this engine 2.0L TDI. While I had it off, cleaned some of the hoses and Air cleaner housing with water and WD40. Re-assembled everthing and engine starts normally and runs smooth but no power. It does accelerate slowly. Got a check engine light and a 16683 code(low boost below regulation). The next day I got the code 16486 (MAF something). I reset the codes and drove it again, did not get the check engine light but got the same codes when I hooked up a scanner to read them. I checked the VNT actuator and it moves when the engine is idling. Also put some suction on it and the actuator moved and stayed put until I released the vacuum. Checked all the hoses to and through the intercooler to the intake. All were tight. I cannot find anything obvious, could I have damaged the MAF when cleaning out the air cleaner housing with water and WD40? And would the MAF cause low boost like this. Kinda weird that I received the code for low boost way before I got a code for the MAF.
Any ideas or help would be greatly appreciated.

Its a 2005 Passat GLS TDI with 81k miles on it.
By the way it was running fine before I messed with it.:panic:

Thanks,
Bart
 

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What a bummer. On every tdi site I've been on ,the maf seems to be the cure for loads of issues and personally wouldn't go near it with water or wd40. A lot of people give the actual plug a good clean with contact cleaner but avoid the actual maf. You just unplug it, spray contact cleaner into the plug, put it on and off a few times then plug it all the way home. If that doesn't work it could well be a new maf I expect. I do sympathise with you however as I've often learnt the hard way.:D
Also worth unplugging the maf to see if there's any difference as this can help your diagnoses.
 

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You probably disturbed a vacuum line which is causing the low boost. Before paying replacing the MAF, log it with VCDS to make sure it's really the problem.
 

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Discussion Starter #4
Thanks guys found out it wasn't the MAF sensor. Checked all the vacuum lines and they were good. I think the guys that took my Turbo apart to inspect it maybe put it back together wrong. They are going to take it apart again tomorrow and check the VNT geometry. That's what they said!

Bart
 

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Discussion Starter #6
Took the Turbo back to the turbo shop and they found that the seal between the exhaust side and the intake side was out. Surprising to me that the car would even run that way because it was sending the exhaust back through the intake (partially anyway). They fixed it for free. I put the turbo back in and it's back to running pretty sweet.

Bart
 
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