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Low boost under 3000rpm

Saxk

New member
Messages
2
Likes
0
City
Oettingen
State
Non-US
Country
Germany
What I Drive
2009 S3 8p Sportback
#1
Hi Guys, im new here.
I have a 2009 S3 sportback with some turbo/boost issues.
It all started when i went on holiday last year, i came home to a missfire, changed the coil packs and that fixed the missfire, buit it still lacks power.
I did some VCDS diagnostics, and turns out that I'm underboosting until about 3000rpm.
Ive bought a smoke tester and ran multiple tests over the last few months, i never found a leak in the charge system.
PCV valve is fine, ive even blanked it off and it made no difference.
The recirc/dv is also fine, physically and i also bunged it off both ends to see if it would improve low end boost, it was the same, so i assume this is al
VCDS throws up no faults. the N75 is pinned at 95% from about 1450rpm, as it should do. Im aware that its possibly not doing its job, even tho sitting at 95%, it may have a leak/damaged internals.
Before i remove the turbo to inspect the wastegate and its actuator, is there anything else i can try?
Here are a couple of VCDS graphs, one with 7.42 is a 4th gear pull, i forgot to log the N75 value.
second graph withj 4.92 time stamp is a 3rd gear pull, and as you can see the N75 is at least giving a signal that its max closed to built boost, it also drops to 40% at full boost, as it should.
Today im going to test the N75 but clamping the hose closed that runs to the acutator, to see if it builds boost faster and then overboosts, ill be careful not to overboost it past 3000rpm

I also jsut not got a fault code P1531 - 004 open circuit. so the camshaft adjuster is not reading. could that be causing the cam lobes to be in the incorrect state at low rpm and thus slowing the turbo spool up?

Thanks guys

Brad
 

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Saxk

Saxk

New member
Messages
2
Likes
0
City
Oettingen
State
Non-US
Country
Germany
What I Drive
2009 S3 8p Sportback
Thread Starter #2
1781616636731.png

managed to fix the cam sensor, its contact plug is broken, but i got it to work. new one ordered. looks fine tho right?
 


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