Testing a diesel generator fuel injection pump requires a few steps to ensure that it is functioning properly. Here are the steps to test a diesel generator fuel injection pump:

1. Disconnect the battery and remove the pump from the engine.
2. Clean the pump thoroughly with a cleaning solution to remove any debris or dirt.
3. Inspect the pump for any signs of wear, damage or leaks.
4. Check the internal components of the pump for wear and signs of damage.
5. Ensure that the pump's plunger and barrel are clean and free from any damage.
6. Use a fuel pressure gauge to test the pump's fuel pressure.
7. Check the delivery valves for wear or damage.
8. Test the fuel shutoff solenoid to ensure that it is functioning properly.
9. Test the pump control rod to ensure that it is working correctly.

The testing process may vary depending on the type and model of the diesel generator fuel injection pump. It's always best to refer to the manufacturer's guidelines for specific instructions on testing a particular fuel injection pump.