checked all my check valves, replaced all my hoses etc, etc. still losing boost at higher rpm's. my last and final idea of what this could be is the vacuum chamber is bad. how do you check it. i hooked up a mity vac and tryed to apply vacuum to it and it didn't mantain it. this probably means it's leaking right?

 

i would say that it is bad

 

I got the mity vac with the pressure/vacuum gauge.
That little gauge and that pump has been more useful in testing vacuum and pressure related stuff more than anything else.



www.mityvac.com

 

What exactly is your boost pattern? Is it high before transition and low after?

 

So hypnotic...

 

dont have a guage so can't tell you the boost pattern

 

Install a gauge before you do anything else.

 

Simple minds are easy to manipulate

 

while you're not using it it doubles as a nutcracker for your living room coffee table

i'm bored

 

I thought the chamber only held pressure due to a check valve being in the line going to it.

 

I thought the same thing when i tested mine. When i took it off, it held vacuum fine. When you test it make sure the hose is tight on that tester and on the vacuum chamber.

I have tried to fix my boost pattern since i bought the car, changed almost everything possible except turbos and still have 10-8-8.

 

Anyone know what's involved in replacing the vacuum chamber? I think mine is bad--it does not pass the key on key off sequence when checking the charge control actuator rod (pulls in with key on, and pulls out when key is off)...

 

yeah unbolt it and take it out

 

Which chamber, as I remember the top one is pretty much cake, you have to take off the turbo outlet pipe and some bolts and hoses. The front one behind the PS/etc is a little harder, you have to remove the alternator and its adjuster bracket etc to get it out, it pulls straight up through once you've gotten everything disconnected and unbolted, its pretty evident as you take it apart how it will come out when you know it has to come straight up.

 

Yeah the vacuum chamber is the one I'm replacing. So I have to remove the alternator? Well at least I don't have to remove the power steering pump LOL Thanks!

 

You'll need a <12mm? iirc> box end wrench to get the one bolt that goes into the bracket for the alternator out <its actually like through the power steering pump bracket, when you start getting stuff apart you'll see what i mean as you find whats still holding it in>. It's really not a super hard project from memory. But I definately didnt have my PS out to do it.

 

I'll let you know how it goes. I'm doing the job tomorrow!

 

Out of curiousitym
How much does that shiney little tool cost? (he said shiny little tool!). Their site is the typical ambigous "ct us".... Thta looks like a handy little bastard!

GEB.

 

Well replacing the vacuum chamber was a bee-atch!

Tear down involves removing the strut brace (R1s/R2s), intake piping, elbow, throttle body, oil filler neck, and alternator.

Tools required are ratchet socket set with u-joints and big heavy screw driver to move the vacuum nipples out of the way when you have to put the alternator back in.

Yes the secondary turbo comes online like it's supposed to now.

 

BTW, the old vacuum chamber wasn't bad per se. It was just filled with oil; thus there was no vacuum chamber since all the air space in the chamber was filled with oil.