Quick specs - 89 T2, rtek 1.7, 550 primaries 750 secondaries, three inch exhaust.

About a week ago, driving on the freeway, I went to boost and couldn't get the needle past 5 psi (normally boosts around 10). Figured it was a vacuum leak, but a minute or two later it started boosting just fine. I sort of shrugged it off.

Did it again today. Couldn't get the boost over five. It "feels" like a fueling issue, as the AFR's seem to spike high a bit when this is happening.

Couldn't find any vacuum leaks. Any suggestions?

 

doubt it is fuel related unless the car just falls flat on its face and sputters trying to go into boost.

sounds like a ripped hose that is bleeding off pressure intermittently, tears will generally give lower boost levels when fully warm versus a cold engine which will perform relatively normally. only other thing i can think of is a sticky wastegate door.

 

You thinking the wastegate is stuck open?

 

Did you try testing the wastegate actuater??? Its possible, my s5 wastegate went out on me, I had to purchase the internal wastegate from himniracing.com... good luck!!!

 

not very common but it can happen. something could be rubbing on the rod and holding it open, something jammed into the canister or the flapper door hanging open due to buildup on the bushing or something stuck under the door.

 

I had a turbocharger that had a worn wastegate shaft bushing...where the arm passes through the manifold. This caused the wastegate flapper to sit crookedly on the wastegate opening, which caused boost response to suffer.

 

Looks like I'll tear it apart this week and see whats up. I'll post my findings. Thanks guys!

Might be a coincidence, but it seems more prone to doing it if I drive the car, park it for 10-30 minutes somewhere, then drive again.

 

How does one "test" the wastegate? Whats the stock wastegate set to open at?

 

On a Tii it should holding boost at 8.5lbs