That'll be because of the masses of air now in the system...
HAve you fiddled with the fuel filter? If no leave well alone and do the following.
Slacken the return banjo on the back of the injection pump. Crank till it spurts diesel and nip it up again. If it still wont start crack the injection pipes on the top of the injectors (probably only need do one) and get that to spurt diesel.