I have a problem with my waste gate, a Tial 40, after that i found disconnected the piping that starts from lower port and connects to intake, before throttle body, it seems to be no more able to keep the mechanical boost cut of 11.5 psi that normally it keeps,or better, it seems to keep the nominal pressure for a few seconds, then it starts to become gradually higher and arrives at about 30 psi, but without pulling really hard like it should do at that pressure level, i tried excluding AVCR solenoid and also checked for leaks, but nothing.. Could it be a waste gate failure? It would be quite strange, i'm mapping a brand new engine, and also the wg has done no more than 500 km from new.
Any ideas? I need to purchase another waste gate?
Thanks in advance.
Gianluca.

 

Nobody?
In this period, thinking that it was a waste gate problem, i tried 3 different tials, a 40, a 44 and a 46, but the problem is the same, i tried excluding the avcr solenoid, changed all air fittings and connections, but with no results.
Any ideas?
I'm thinking about disassembling the head for verifying is something went wrong, or even the turbo, i'm in total confusion....

 

Remove all lines from the wastegate and go for a drive. If you have at least a 1.2bar spring you should be able to hit 28 psi easily around 4300-5000rpm. If you can't hit this pressure, you may have a spring issue or a bad wastegate diaphram.

 

Just done, i have a 0.8 bar spring, and removing all the lines, at 4000 rpm, i have about 30/32 psi, approx. 2.2 bar.
The very strange thing is that verifying the pressure on the line that comes from the intake, in proximity of the waste gate, i have the same pressure that i have into the intake manifold, measured by two map sensors....
It's like the waste gate is not able to evacuate gases enough, but it's not possible, i changed nothing since it worked fine.
I'm in panic, i have no idea of what i have to look at, in theory everything should be ok, but it does not work.....
One thing is sure, it is not a waste gate problem, i changed 3 different units, a 40 a 44 and a 46 and nothing changed, always the same problem....
I'm thinking about disassembling head, turbo and all air system and checking them, but i'm not sure of what i have to search, a leak or what other, in theory i should have no boost, but i have exactly the opposite problem, i have no control on it...... ( Excuse me for my english, please take patience, i'm italian and i'm doing my best..... )

 

i need more clarification of the problem. Is the problem:

1. The pressure is reaching 30 psi and I can not lower it?

2. The boost pressure is increasing very slowly until it hts 30psi?