I have a boost issue, no codes, my stock n75 valve is toast so i changed that to a mbc a few weeks ago, it worked, then all of a sudden i was only boosting at 5 psi tried adjusting it and no change, the mbc worked on my buddys jetta so its now there. i bought a new n75 valve have it installed and not even 2 psi of boost. it boosts late when the car is cold and when the car is warm it doesnt boost at all. boost leak? pos turbo? any ideas? seems to be alot of smoke coming from the exhaust as well.
thanks

 

sounds like ur in limp mode, i would have a diagnosis even if ur not throwing a cel

 

yup, sounds like limp mode. disconnect the neg terminal turn on the interior lights let it sit for 10 min. reconnect it and you should be out of limp mode. what did you set the mbc to? sounds like you overboosted


make sure you have your radio code tho

 

if theres a lot of smoke coming out of the exaust... that could be ur turbo going... but i would ask someone that knows more about ur situation

 

its not limp mode, i scanned it with the vag-com, i disconnected the terminal. still very little to no boost. getting a boost test done this weekend.

 

if you vagged it, and that is all goo, you probably have a blown turbo of a massive leak some where. good luck with the test, keep us posted

 

I have the same problem with my car at the moment except that I am making ZERO boost =(

 

Does your car sound different at all? Hissing noise? Loud exhaust noise or something? I had a bad exhaust leak and it caused my car to not boost at all. It was right at the manifold to turbo bolt. One of them was backed almost completely out.

Josh

 

no hissing sound,no loud exhaust sounds, its strainge, like this morning to work it was boost 15psi, on the way home from work 15 psi like where it should be, after dinner i go to pick up the gf from the subway station and i only get 5 psi on the way there, and 5 psi on the way back, its really strange and has been too cold (-17) to do a boost leak test.

 

I did the diode mod a few months ago and returned it back to stock, would if any chance the wires are touchingcould be shorting each other out cause this?