wastegate stuck open...car makes no boost

[Blk95gs]

I just installed a ported EvoIII 16g turbo, ported EvoIII mani, 650cc injectors, intake, FMIC,3.5" GMAF, Ramchargers MAFT, RNR 2.5" o2 elim. downpipe w/external dump, and a 2.5" cat back on my car. i drove the car with no cat back on, and it made 11 psi with the boost controller off. after i put the cat back on, the wastegate was just stuck open. now it only builds 2-5 psi. what would suddenly cause that crap? all parts were brand new upon install

 

[leet]

Well, start at the basics. Is anything obstructing the wastegate actuator arm? Vacuum lines hooked up correctly?

 

[BitAddict]

Have you taken off the wastegate and manually checked it? Not sure about 2Gs but its easy on a 1g? maybe the spring is just stuck?

 

[Tarantula]

Try taking off the wastegate actuator arm and opening the flapper and closing the flapper. This is to make sure it moves freely. Than grab hold of the Wastegate arm and pull on it. It should not move unless you really pull hard. If all checks out and you have a boost source on the intercooler pipe, you can hook up a vacuum line straight to the wastegate actuator. The internal spring pressure will only allow under 15psi before opening the flapper. (Not sure of the spring pressure of the EVO III 16G) The first test is most likely gonna give you results because the 16G does not have a boost source like the garrett setups, unless you put one on there either on the "J" pipe or tapped the turbo (theres a screw hole right on the compressor outlet that is not used. drilling a small hole through it and screwing in a 1/8 nipple will allow a boost source.

 

[Tarantula]

Heres the site where you can find out how to put a nipple on the 16G outlet on the compressor housing. Scroll down to other tips...

http://dsm.aenewton.com/16g_14b_rre.htm

 

[Blk95gs]

the wastegate does move freely, so i took off the 16g actuator and put on my 14b one. now the wastegate works fine, but i have another problem. the car only makes about 10psi, and i hear a loud whirring noise coming from either the turbo or an IC pipe. there are no boost leaks, but my boost controller is tapped to the line coming from the BOV. i guess that is not a very good boost source? what would cause that