Dont panic ive done a similar thing. When changing the fuel filter i removed both hoses without clamping. To they both just ran downstream to the pump and to the tank. So completely air filled all fuel lines. This technique may not be right but it worked for me. Put a lot of fuel in TANK.
Keep in mind your going to have to pump this system like 5 million times... :/
First up. get either your filter or a new filter. Fill it up with fresh diesel. At the fuel filter housing, Connect the fuel line from the tank and UN-connect the fuel line to pump so resulting in an open system.
Put filled filter together. Now..... what i did was pump and turn the filter on its side and upside down maintain pumping during this procedure.
You may feel that the plunger goes hard upside down then as it return to level it will be soft...
I kept doing this, the plunger seem like it cannot remove large quantities of air (either that or mine is stuffed). Remember top fuel filter up with diesel to the BRIM.
Yes some might squirt out... and then it might just stop.. just keep trying this technique until it start to pull the fuel from the tank. This will be successful when you find that each pump of the plunger pump outs even amount of fuel consistency (filter level, not upside down).
Once you get to this step (and i hope you have a good battery or a mate to jump start you). Fill the hose that leads to the injector pump with fuel via a syringe. then clamp it back onto the fuel filter housing. Now pump it like you've got a purpose until it goes rock hard.
Now start cranking. all the air is the system should only be in between the filter and the injector pump. Not sure if this is correct but due to the zd30 not having a fuel priming pump like petrols the injector pump can only create a pumping pressure if it has something to pump....eg fuel?
anyway I started to weaken my battery so i got a mate with good NRMA cables to jump me when i started to get low and WALAH it finally turned over after.
NOTE: don't just hold the key on crank.... do it it bursts, say 5 seconds then off... let it sit then 5 seconds again as i don't think the injectors/pump like pumping just air constantly, someone can sort this out.
Keep in mind the system will be Rough as guts for a bit. Depending on how much air you have failed to removed. Mine went for around 20-30 seconds. Didn't want to idle and just stall so keep the revs on (say 1500-2000) until its it is idling on it own.
This procedure sounds strange just made it up as i went and it worked.