Boost problem

[Madmile]

I have a 01y ayp Ibiza cupra, its is running a superchip, 007dv, cat back exhaust and induction kit. When u floor the car the boost pressure rises to 19psi, and backs of to 12psi approx. I contacted superchips and 19psi peak seems to be correct by there standards, and 12psi after overboost. The problem is the boost pressure when it drops towards 12psi judders up and down between 10-12psi it does not sit static at 12psi. Boost guage checked on another car and it is okay. Superchips dealer said it was a waste gate actuator fault not a chip fault. But the only way to find out if the waste gate is faulty is to remove chip(£70) take to Seat dealer and check on vag-com. Any suggestions will help

P.S Yes I know, the superchip will not be re-fitted.

[Sim]

This effect is called "surging". Replacing the N75 valve may (or may not) help.

[Madmile]

While checking aroung everything i found that the DV ( forge 007 diaphram)has 3 tubes coming off it, i know the small one at the top is the vacume pipe, i dont know what the other 2 do. But the longer one out of the 2 which is not opposite the vacume pipe was loose, it screws into the body of the DV, used a little locktight and tightened. Before doing this i blew into the pipe and pressure was leaking from this joint, could this be responsible?. When i blow into it now there is no pressure loss.

What do u think? cheers

[Sim]

Try it and you'll find out ;)