Its either the IP has taken a gulp of air or it has died on you, been there done that in both cases. If you had even 1 or two good glow plugs with a manual swithc you'd get a start if everything else was right. The only other possibility I can think of is that it's in fact electrical and the fuel shutoff solenoid is stuck shut=no fuel. You have driven this thing recently and it ran good once running, so we know the motor's not dead, you should have compression, obviously you have no problem with the batteries or starter or a free path of air to the intake so you should again have heat and compression... fuel? You say the injectors are weeping at the top with the nut off? That may mean you have fuel but it may not either. To be sure, you have to observe the injectors while the engien is cranking, you should see bubbling or small micro squirts coming through the looseneed injector nuts, or a slow drizzle down by the leakoff Ts. If not, you aren't getting fuel and what you're seeing is residual from the leakoff tees from the last time it did run. If you don't have fuel as described above, your injectors don't have fuel, either because the pump is dead or its air locked. You need to bleed the air out of the system crank the motor over with the injectors loosened and glow plugs off no more than 15-20 seconds at a time followed by a 2 minute plus cooldown, before 15-20 secs cranking again. If the pump is good and you don't have any massive air locks or leaks, you should get fuel everywhere within a few cycles of this, when you do, tighten all the injs back down, heat the glow plugs and crank until it goes. You'll need to rev and feather the throttle a bit till it smooths out when it does go. If you still have problems you'll need to loosen the IP inlet line, crank till you ahve fuel there, loosen the lines(at least the ones you can easily reach) on the back of the IP and bleed those for a few cycles and repeat the standard bleeding procedure. If even that doesn't work, the pump either has a dead fuel shutoff solenoid or is worn out of tolernaces. Good luck, a bit of help and another truck to jump you, jumpbox/battery charger is a real good idea.