low hpop pressure

[tecelec1]

2000F250/250kmiles, AE scan states, 900 to 1200 then back to 900 then down to 450,1.5volts, 65%icp duty cycle
i have 45lbs pressure at hpop resavouir,
i have T500 hpop, took it off installed my old good hpop that never got around to sending back identical readings
have another 7.3 to benchmark with, cold it generates 2400psi,1volt,14%
changed ipr and icp no change
any ideas?
thanks for the help