[Paul Thomas]

That is basically the design i was thinking of. All of the hand pumps i have seen so far reach at least 200 psi. The injector opens between 15-18 bar (213-256psi). To test the injectors you should hold the pressure 2 bar below opening pressure and wait. If no droplets, ie: leakage, occurs in 15 seconds then the injector is ok.

Paul