Low boost problem

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Mar 7, 2002 | 03:22 AM

FASTandSILVER

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Joined: Nov 2001

Posts: 21

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Low boost problem

Hi, I have a A4 1.8TQ, manual, 1998 model, 150PS and recently upgraded to K04 + chip with this setup:

13psi normal boost - 16 over boost (yes very conservative setting but this is the most common chip setup available here in Greece).
The car operated fine for about a week but after the first continual WOT at 5th gear in the highway, the boost pressure dropped from the 13psi to 6psi. Since then,when at 4 or 5 gear and WOT ( 3500 RPM and more) the pressure hits about 13-14 psi and then drops to a steady 6-7 psi. When under no such a load,
( changing from 1 to 2 to 3 gear) the pressure hits the specified 16 psi and then drops to 13 psi).

First of all I (visually) inspected all the hoses and find them OK
Then replaced the stock BPV with a Forge one but the problem continues

I have also tested the following using Vag-com tool

* No DTC errors
* Not pinging at all ( vag-com tool - group 20)
* MAF sensor - OK
* Wastegate bypass regulator valve - OK

I thing maybe is a boost leak problem that a visual inspection cannot find.
Any idea for what else can be faulty?

Thanks,

Kostas Tsonas
Athens/Greece