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Discussion Starter #1
charge pressure-positive deviation
Passat APU 1.8T 2000
I have logd some data , but I can't make any sens out of it.

 

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The code means the actual boost pressure is consistently higher than the requested boost pressure. That suggests your N75 and/or its associated vacuum hoses are not working properly.
 

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Discussion Starter #3
Update

I have tested the N75 resistance and it is within the range, vacuum hoses have no visible damage, so the next step I think -- TURBO !!!
 

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Two more ideas:

1) Maybe the air pressure sensor is malfunctioning.
2) Install an air pressure gauge, so you have something to compare your data to.
 

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Discussion Starter #7
boost gauge

I have mouted boost gauge. It seems that I have full boost ~7psi at some times and at the other times 50% ~3,4psi !!!
 

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You will not have full boost all the time. Put the car in 4th gear and drive up a hill at full throttle. If you get 7-10psi, then it's working right.
 

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This is my gauge.
So on the stock engine full bost is at 10 psi, the most I got few times on 2nd gear was ~9psi
You need to allow for the results to vary from the official spec, because there's room for error in the gauge and in the boost controller. What really matters is whether or not you can get the same results under the same conditions -- run up the same hill several times in a row on the same day, full throttle all the way. If you get the same boost every time, and if the boost reading is somewhere near the official spec, it's very unlikely that anything is wrong.
 

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update on turbo

So I made few runs and my turbo runs on 3psi no more, then I disconected pipe going to waste gate and went for a drive. First press of gas pedal and my gauge went to ~15 psi and dropt to zero. I connected pipe to the waste gate back and I have zero boost. N75 has resistance 29,4 but voltage supplay is 2.7 V. Big question is did I destroy my turbo !!!
 

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Discussion Starter #12
What a relief

Drove all day without boost and then suddenly bang and I’m driving all the time with 7-8 psi, don't understand it but I'm glad my turbo is ok. I will have to check if I have steel over boostcode.
 

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Discussion Starter #13
Partial boost

Well it seems that I have full boost sometimes, so I think it can not be a vac leak, would faulty dv produce overboost code ???
 

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Discussion Starter #14
Partial boost

Well it seems that I have full boost sometimes, so I think it can not be a vac leak, would faulty dv produce overboost code ???
 

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Discussion Starter #15
partial boost

Well it seems that I have full boost sometimes, so I think it can not be a vac leak, would faulty dv produce overboost code ???
 

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Discussion Starter #16
Solved

Bump
Well sorry for delay but just recently I had more time to get hands dirty:wrench:, so I took out turbo and cleaned it.
No more problems I have full boost. :)
Now I changed dv and in two days getting chipped.
 
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