To start open bleeders, you can fill filters proir to installation for less frustration. There are times more then one injector needs to be loosened at once but with most systems you can only do one at a time.
Hope this helps. On my Grand L3130 The procedure indicates to
1pen the fuel cock on the filter,
2:Open the air vent cock on the fuel injection pump.
3:start the engine and run for about 30 seconds and then stop the engine, 4:close the air vent cock
This is the procedure I have used after replacing the fuel filter.