Sticking Wastegate?

[Jackyll]

I've been boosting at 19psi since last spring, but for the past 3 months or so the car won't get up that high. Basically what happens is this... when I got WOT the car accelerates like it always has until it get to about 14psi, then it will studder and buck while the boost gauge bounces from 14psi to 19psi and back and forth. I took off my MBC and it did the same thing. I also swapped in a working wastegate actuator and that didn't solve the problem either.

Could it just be that my wastegate is sticking? If so, is there a way to clean it out and how would I go about doing that?

Thanks

 

[v2ner]

If the WG was sticking, you'd either have too much boost or have no boost at all. Did you do the basics yet? Such as plugs, wires, boost leak? Did you try turning the boost down?

 

[LunarEclips]

ive heard of the wastegate flappers inside the exhaust housing sticking before. maybe you might want to check that.

 

[Willicuddy]

A wastegate expells excess pressure once receivingt a signal from the ECU or in your case the MBC. If it was stuck open the turbo would keep on spooling past 19psi. It would not cause a shudder and cause the boost to bounce between 14-19psi. Also, pull on the wastegate actuator and if you can move it by hand then the wastegate is functioning. If the watsegate is not the problem you might want to check what v2ner has suggested.

 

[Jackyll]

Plugs and wires have been replaced already while this was going on and didn't change anything. I tried turning the boost down and up on my MBC and it didn't change anything. I also removed the MBC and put it back to stock and it still did the same thing. I haven't checked for a boost leak yet though. I will try that on saturday.

I forgot to put in my first post... that when i replaced the wastegate actuator with the known good one... the bucking got worse, but now everytime the car bucks the BOV goes off, it didn't do that with the old actuator.

 

[DSMcrazy3]

If it was stuck open the turbo would keep on spooling past 19psi.

Actually if it were stuck open, the turbo would not reach 19 PSI, it would actually have a hard time building any boost at all.