so lately i have had some boost issues sometimes i get full 18psi and other time i only get 5psi, i was starting to hope that the turbo was fine and the turbo to manfold gasket had blown out or started to leak but to night on my way to work im on the highway in fouth gear and i get on it to pass someone and i hear a boom and then no boost so i coast then i try to get some boost out of it and my gauge will hit 5 then it surges then nothing. Can it be that maybe my map sensor has quit? i don't have a check engine light (yet) and my vag is at home which i will scan when i get home today to see if any codes have shown up, is there any other reason that this could happen? or is my turbo toast?

 

if your turbo going bad you would hear grinding sound something like huge hummer drill. having leak like u have if your gasket blown out most likely you would see and hear the leak while inspecting it, even then don’t think you would loose all the pressure… first I would check for any leaks, not just inspecting vacuum hose, but check for leaks using compressor.
once again sound of dying turbo will scare the hell out of u.

 

it will hit 5psi then it kinda feels like the rev limter kicks it. im running a vag on it right now. it has not made any fun denist drill noises

 

p1555 charge pressure max limit exceeded

sounds like it went in to limp mode

 

that could be your problem, have u tried diode mode? mean if your turbo is fine and you have no vacuum leaks , try cleaning maf sensor and do diode mode... it should keep you out of limp mode

 

what is diode mode

and how do i get it out of limp mode?

 

oh and i have a manual boost controller (forge 3 prong) which i had moved last week is there a change that i but it in backwards? bottom prong goesto nothing leftgoes to waste gate and right goes to n75 valve. i would spike at 22psi hold at 18-15psi

 

to get it out of limp mode you have to clear the codes and to keep it out of limp see here.

 

but I would still check for blown gasket and for any leaks … do the simple stuff first…

 

after the engine cools im going to check around the turbo and manifold for any leaks

and my car looks just like yours minis the bagesand taillights, mine is black with black 18" falkens