I have a 88 tii that was recently rebuild and has near perfect compression, and i'm having boost issues. Now the issue is when i have the boost controller (greddy spec 2) on it won't boost above 7psi..... it will go up to 9 then drop down to 7 and just fluctuate. with the controller off on my pfc commander it shows that its boosting at around 4 to 5 psi constant. i tried using a different solenoid, that didn't work, then i tried using a different unit and still the same. is my turbo blown? or is it something else?

 

Are you sure you have the solenoid connected properly? If you still have a stock style turbo with and internal WG, the COM hose goes to the actuator and the NO goes to the compressor housing.

Was your engine rebuilt for blown apex seals? If so you could have damaged your turbine wheel.

 

or you could have a crack in a hose somewhere, once it reaches a certain pressure it is bleeding boost off. i would also build a pressure tester and see if there is any leaks in the system.

 

i did a leak test and i changed all the vac hose just incase. Also, i think it mite be the turbo too, because everything was working before the rebuild. i just really hope its not. is there anything else that could cause it???? i think i have a short somewhere too, would that affect the boost controller?

 

Did you remove the plastic plug from the NC port on the solenoid? I have seen this a few times, it plays havoc trying to control boost as there is no way for the solenoid to vent.

 

Or how bout those settings on the back of the boost controller??? I remember i was having issues one time After putting in a new turbo.
once i fixed those setting everything worked as normal.

 

If it turns out it is your turbo, I've got 2 s4 stockers for sale, both worked perfectly fine when removed, one of them with roughly 6000 miles on a rebuild and has a ported wastegate.

 

^ how much for the ported wastegate s4 turbo? My turbo needs to be ported but it is cracked so I don't see the point.

 

i don't recall the last time i saw one that wasn't cracked... do people even search before assuming anymore?

 

PMed about the turbo with ported wastegate.

 

Okay, i it is the turbo thats bad. We tried keeping the acuator shut all the way without the boost controller hooked up and it took years for the boost to build up to 10 psi. so the turbine is damaged and i need to get a new turbo.... boooooo!