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Discussion Starter #1
Hi All,

Before I start, Thank you in advance. This site is extremely helpful in diagnosing issues.

So I get the code for P1556 - Boost Deviation Negative. Here is what I have done so far.

1) Checked movement of actuator. Moves alright.
2) Checked piping and all vac lines. Looks good. Boost test came out very well
3) Changed Fuel filter a 200miles ago.
4) Intake was cleaned 1000 miles ago.
5) MAF was tested. Vag-Com reads around 300-400 at idle.
6) N75 works well. Checked with Vag Com and its reading fine.
7) Checked the VNT Lever, and its sticky.

So, looks like I have to clean the turbo, any suggestions?
 

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FYI, "Vag-Com reads around 300-400 at idle" just is at idle, you have to datalog it to see what it's maxing out at as well.

Also, since you joined, I made car model/year required info for new members. Please add it to your profile or list it every time you post, thank you.

If you disconnect the VNT lever from the actuator rod, it will let you isolate what is sticking. Check that first. Also, if you long term plans include any power mods, it's worth considering buying a VNT 17 turbo now and sell the existing turbo as is. :)
 

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Discussion Starter #3
I can do the datalog for the MAF tonight or tomorrow.

I adjusted my profile as requested!

I know its the lever that is sticking out of the mix. The actuator moves just fine. Just to trouble shoot, I had a spare working actuator from a seized turbo installed, and it worked just as well. The lever was noticeably harder to switch unlike the end video in your VNT repair thread.

I will consider it, but we shall see. Funds are pretty low right now.
 
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