I have been boosted for a while. i do all my own work. here is the problem. i run a stock b18c with a t3t4b .48 turbo. i had a pwm boost controller now i am just running on spring. and once i hit 5 psi sounds like it is shotgunning out the wastegate. the outside temps are very cold. what are symtoms of a bad wastegate diaphram or it almost acts like the exhaust is plugged. if i bring power up slow no problems. btw this is how it was before i went with pwm. and it worked great in all power bands. tell me what bad wastegates act like. if it holds a steady pressure open does that mean its good.
turbonetics 35mm evolution

 

What are you using for engine management?
What fuel system do you have?
Do you have a wideband oxygen sensor gauge installed?
Has the car been tuned?

 

Sounds lean. But need ^ that info.

 

enginemanagement is Neptune rtp. running e85, 255 pump, id1000's, car is tuned a little lean at 2000-4000 rpm. Nothing unacceptable. all the datalogs show 12:1 af.(using reg gas as basis). when under boost. I recently took off boost controller an just went direct to bottom of wg. Lacking self discipline for boost control. the engine ran Fine for last 6 monthes. I will try extra fuel. it really sounds like the wastegate is either not staying off seat and creating a popping sound. Runs perfect except when going into boost. turbo compressor spun freely like normal.???
btw their is a wideband installed and is working.

 

I built up a new cal map and it runs like a champ. I do believe it was to lean.(lucky i didnt do to many pulls) Also I removed wastegate and at first it only wanted to come off seat 1/8 in. I put 20 psi to it with shop air turns out it was hung up. also i had the bov adjusted to tight. thanks for the tips an gettin me to look at a few more things in the whole picture. If only i could afford a catch can setup I think the engine would be easier to tune at 15 psi to 18 psi. turbos dont really like it when your wasting their power. btw i found a few exhaust leaks and i think they caused the wideband to read richer than it was. (not sure what exhaust leaks upstream of wb act like)thanks guys