D2 D3400 injector testing

A satisfactory valve should emit a completely atomized spray with a sharp cutoff of fuel and no dribble.
On the test apparatus the injection pump would be set to a .350" rack setting to establish an adequate flow rate for testing. Your slow pumping would not apply.

Yes, there should be a distinct opening (poping) at the correct pressure,
1500 psi for this particular injector.

Picture of valve being tested vs known comparison:

That is exactly the info I was looking for. Thank you.

I sent the injectors to Bill Walter for rebuild.

Would appreciate hearing some feedback on how the service works out. I don't recall ever hearing any results information nor much in the way of BB input on injector discussions.

Sure thing. I will test them on my pump setup when I get them back.

HF hole punch pump, a tee, gauge, and a spare injector line. Drained the hydraulic oil and filled it with diesel.

Seems to work well!