The power inserter you're attempting to use does not pass 22khz, because it's intended use is ONLY for SWM LNB's/switches, that do NOT even use switching tones, as it is not needed for SWM (stacked) systems. There's other DTV (SWM) power inserter models made with different voltage outputs & those will NOT work either.
If the PI label has SWM on it, it's not going to work on older, multiswitch technology you evidently are attempting to work on...you'll need to get an older PI that is made for that. And considering there's been umpteen varieties/brands of this older technology that have been made over the past couple decades, it's hard to recommend something specific without knowing exactly what's in your LNB/switch system.