You can unplug the boost control, or if its on one of my looms just pull the fuse but i don't think that is your issue.
have you monitored the AFR?

Data is the key, if we can watch live data from the ecu you can quickly establish issues,
try unplugging the green lambda wire so it runs open loop,

What springs were in the old ISCV? are they correct? and the bottom one stronger than the top one?