Wastegate problem?

I just bought an '87 200sx turbo, as I need a second car. I am not new to the turbo world as I swapped an SR20DET into my S13. But I am new to the CA18 world. Anyway I bought the car off another club-s12 member from Calgary, Alberta. Today I drove the car for the first time, and for the first few minutes it was boosting fine, but then as soon as I hit about 2500 RPMS and boost was around 3psi you could hear the air rushing out (much like a BOV) continously. Boost sank down to 0. Of course it then started to bog. There is no boost leak anywhere in the piping and I already took off the BOV and plugged the hole as I thought that might be causing the problem. Do you think my wastegate is leaking? Air has to be escaping from somewhere and I cant think of any other place. Let me know what you think.

Could be leaking from the pop up valve (emergency relief valve) if it's still on there

Could be leaking from the pop up valve (emergency relief valve) if it's still on there

Where is that?

Its a 1 1/8 plug sitting on top of your throttle body and its got a round plate riveted to the top and if thats shot all your boost will vent out there instead of going to your engine.

It's actually behind the throttle body and screws into the top of the intake manifold near the firewall. just unscrew it, and replace it with a 1" pipe plug from any hardware store....they got them in brass or galvinized, and sell for about a buck or two.

Figured it out. Boost leak!

deathbyboostleak