I can only speak in general.
The Injector is not supposed to leak any Fuel at 75 psi.

One of the tests is that you bring the pressue to 200 psi below the opening pressure (the actual measured opening pressure of the individual Injector); if your Pop Tester has no internal leakeage you should be able to hold that pressure unless the Nozzles is leaking. If the Nozzle is leaking you work the Handle slowly to keep the pressure 200 psi below the opening pressure.

At that point you are allowed x amout of drips. If it is a really good Nozzle it will not drip at all. If it squirts out the Nozzle is shot; same if it drips too much.

Also on a good Nozzle when you work the Handle slowly up to the opening pressure the Fuel will spray out suddenly with no dripping and cut off suddenly. If it is exceptional it will make a chattering or squeeling sound when the Nozzle sprays.

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84 300D, 82 Volvo 244Gl Diesel