From looking at the fuel system your weak points are; 1)the pump itself, not being able to draw the fuel from the tank in asufficient volume at start up (low pressure error) or not being able to generate enough hi pressure at initialcranking speeds or you still have air in the system. 2) injectors out of tolerance with the ECU, leaking injectors. 3) compression loss. 4) glow plugs that aren't working.
the P0040 could be because the battery is flattish after all the starting attempts and not allowing the heated Lambda sensor to function correctly, only worry about it if it continues after fixing the non starting. Might also be worth checking the CAT for blockages not allowing the engine to flow gases correctly.
Not looking good, if you take the one on the right to be correct #4 then 1 and 3 are lean and 2 is way over the top, this may be because the ECU has lost the calibration factors for the injectors or they are just buggered up with crap from the pump.
I take this is the amount coming out of the injector output port? if so they can either be calibrated by a diesel specialist and if they have the data and consult softwarefrom Nissan they can input the relevant codes into the ECU. the other route is 4 new injectors which come with codes ready to be installed into the ECU via said Consult software.
you need to measure the amounts being injected into the cylinders to diagnose a faulty injector not the return pipes as there is always excess stuff that is sent back to the tank on a constant basis, phew you may be lucky yet, I did some crude tests years ago with spray patterns by getting them to fire into a large container one at a time and just looking for an even consistent spray pattern.
How long did it take for that to fill up?
2 and 4 are shot. When I replaced one injector I was advised to do all 4 - "Where one injector goes, the rest will soon follow." This advice was correct. A month after changing one injector the other 3 gave issues.
I was unable to find these injectors on the cheap. Specialist Renault Breakers in Accrington did them for around £125 each at the time. Part number of mine was EJBR03101D, written on the sticker around the injector. Recon were around £100 each.
You should assure yourself that the pump is OK before replacing the injectors, otherwise you risk trashing the new ones, filling them up with bits of metal from the pump.
The ECU needs coding with the new injector codes. You cannot get a DIY tool for this.