big problem turbo stop spooling

[83 intercooled]

Ok Friday I ran the car and it was running good and then 2 days lata found my header was cracked and I welded it and didn't unhook the battery and after that started the car and now rough idle turbo not spooling and when I give it light gas in park boost guage goes down in the vac side not to the boost side

 

[bison]

There isn't enough ex energy to spool it in neutral under normal operating conditions.