this is the video I've recorded today. the car is evo IV, 2.3 engine, no balance shafts.
from the OFH the gauge reads 1.2-1.5 bar at warm idle and ~7 bar at higher revs
but when I hooked up the gauge to the head, where I feed the turbo from, I saw this:

p.s. the sound of the video is crappy, but the engine was running all the time during the filming

 

that is scary....

can you put the gauge as close as possible to the turbo or the point of picking up the pressure source?

not sure if you added any extra lines or fittings when you saw the zero oil pressure.....reducing line length may help for the gauge, as that leads to pressure drop being experienced at the gauge, especially with a small diameter line.

also, not sure how accurate that gauge is at low oil pressure.

 

I drilled and tapped oem banjo bolt from the back and screwed 4AN line in it approximately 15-20 inch long and then attached the sensor to another end

with the same line and same gauge I measure pressure at OFH and the gauge works flawlessly



p.s I'll try and screw the sensor itself straight in banjo bolt wihout the line. if the threads come up the same. don't remember though