Still no boost

[Matt Mann]

Ok I did a leak test found one on the PCV hose and replaced and that leaked stop..so I did a leak test again and I now hear it in the TB so naturally the shaft seals I would assume, so I was going to replace them and I was starting to strip the throttle plate screws, so I stopped, I tried again and again but same thing so I said screw it, so I put it back together to see if it was fixed and and NO. I put 91 gas in the car and It boosts to 10psi and it still flutters and wont rise(everytime). It feels like a soon as it hits around 10 and rises it got a Massive leak and looses boost/power..Would the TB shaft seal be this big of a prob? My car is a 90TSI FWD and small 16G. I fixed the timing and its at 5 degrees. I've recently done the plugs 2 months ago.
Let me know what you guys think

[Matt Demick]

done a compression test? might be getting a lot of blow by

[John Hartman]

what have you got to control boost?  if its stock(solenoid or just hose from boost to actuator) you won't see more than 10.

your exhaust might be getting plugged.

your turbo might be pooched.

what type of bov?  It may be set incorrectly or damaged?

[Matt Mann]

I havent done a compression test. She seems real strong otherwise, as for boost control I have a 2 stage Dejontool boost controller(stock setting with another setting I can make. If my exhaust is plugged where would it be plugged? at the muffler? And my turbo is newer its got 30K on it now. And I run a stock bov. I have squished it (cant remember what the hell you call that term.) Is there a way too check my WG on the Turbo?

thanks again guys

[John Hartman]

most likely the restriction will be your cat, either plugged due to age and contamination or mechanically damaged due to hitting something.

10 psi is basically stock,so thats where it should be if you are running it on that setting.

when you do a leak test, pressurize it to at least 20 psi and see if you can find a hose that pops off or leaks.  not just a little hiss or something a good condition turbo can keep up with a few of those, but something big that is dumping massive air.

[Mike Schmid]

Over the winter my boost backed off to about 10 psi, I figured the spring maybe fatigued but didn't care because lower boost let me run 91 to save a little gas money.  

Anyways, spring rolls around and I turned it up again... nothing.  Kept turning it up, still nothing.  Took the MBC apart and it looked clean, wiped all the parts off and cleaned it with some solvent, reassembled, and she works like a charm now.  

Clean your boost controller out, I was real surprised at how little dirt it took to keep it from sealing up tight and working right.  *for clarifications sake it wasn't dirt per say, more like oily film from the valve cover vent, which has been disconnected for quite some time.

[John Hartman]

wow Mike, thats it?  Some oily sludge made it leak at the seat?

[Kimyee Lai]

Most MBCs have a small bleed hole to let out air in between the MBC and the wastegate.  Otherwise once the ball seats after opening, the pressure gets trapped in there and the wastegate stays open.  That might be why cleaning it helped.  

It does sound like a big boost leak consistent with a torn hose that opens up at higher boost.  Can you describe the boost curve?  Does it take long to get to 10psi, or does it get there as quick as it normally does then starts fluttering etc?

If it takes a longer time getting there, might also be an issue with your wastegate being stuck open.