Converson problems

[SBF250]

all
I installed a check valve system with a VOdesigns pump on my 2000 F250 recently. No matter what I do, the damn thing will not come up and stay at pressure. I drained the tank and flushed all of the lines from the check valves back, no change. Next I changed the filter, no change. Next I removed the inlet to the pump, from the tank, there was a good flow of oil. I tried another pump still no luck. I am out of ideas and patience can body help?

[SBF250]

WTF out of the clear blue now it works.