Dying wastegate actuator
 

I've noticed some odd things going on with my boost since winter, originaly just thought is was the cold weather. I started watching the boost more carefuly an was making 7psi in second gear and 10 to 12 in third, an last night about 14psi in 4th gear. I changed the piece of hose that runs from the compressor to the actuator an that hasn't helped. Is it possible for the actuator to be getting tired finally or have a small hole in the diaphram an bleeding off some boost? Probably time to find another actuator or just get my other turbo an manifold done.

Sounds like boost creep. My S4 wastegate is at 28mm and still cant keep up with my small streetport.

do you have a freeflowing exhaust? if so you will experience boost creep, and it is much more prevailent in colder weather,

The first thing I would check is the movement of the flapper. They like to get stiff from rust and carbon build up and if the flapper sticks shut you will over boost. If it sticks open the boost response will be slow and the turbo won't push much air.

Try pressurizing the vacuum hose which goes to the actuator and verify the flapper opens and closes completely at whatever PSI you want the turbo to push. 14psi? If it doesn't open completely or the bracket which hold the actuator flexes, the flapper is not moving smoothly.

Get under the car, remove the "c-clip" from the end of the flapper arm, and disconnect the actuator arm from the flapper and make sure it swings smoothly. You should literally be able to bounce the flapper with your finger.

If it's stiff, spray carb cleaner around the shaft seal to loosen any buildup then put a few drops of oil around the shaft and work the flapper back and forth.

Also, if you want to run more psi you can dent the actuator. ;)

^ good advice here

could be the spring or the diaphragm?

My wastegate is ported too, but why out of no where would it start spiking? Also no boost controller so it's supposed to be the stock 5.5 - 6 psi. Has full 3" exhaust on it. Knight7 I may have to some of what you listed.

Went to pressurize the gate an found a leak in the actuator line, changed it. Wastegate feels like it starts to open at about 2 psi or so an full open at about 10 psi. Checked the flapper, swings fine. Unfortunately it is still spiking at 14 or so.

Do you have a cat.?

No cat, emission free state so far.