Boost / turbo problem...boost not holding

[Chlippo]

its been two days i am trying to solve this problem with no luck yet so here we are...

lets say on 3rd gear (or pretty much any gear) when i put my foot down and the revs start building to around 4000 rpm the boost goes up to 0.9 bar and then immediatly goes down to 0.4 or 0.5 and stays there till the rest of the rev band.

I tried the N75 and mbc in parallel and still the same prob. Done a pressure test and tested good.

The turbo looks in good shape.

Car have a relentless exhaust manifold and downpipe, 007 DV. AMK engine.
Do you think a crack in the manifold can cause that problem? Boost holds 0.9 bar for just One second!

I disconnected the maf and tried again..same result.

i am out of ideas here...

 

[badger5]

any codes?
sounds like its dropping into limp, usually associated with a boost deviation

 

[Chlippo]

any codes?
sounds like its dropping into limp, usually associated with a boost deviation

No codes.

My freind is suspecting the green spring of the Forge 007 needs replacing. will try that

 

[ruffrida]

No codes.

My freind is suspecting the green spring of the Forge 007 needs replacing. will try that

Bit of a stab in the dark without scanning it, could a number of things to do with your boost deviation.

Has it happened over night, or have you changed something before this happened??

 

[Chlippo]

I am suspecting an error in my N249 bypass, which is leading to a limp mode.

 

[ruffrida]

I am suspecting an error in my N249 bypass, which is leading to a limp mode.

How did you get to the conclusion, have you had it scanned??