It could be that your control box is powering the glowplugs all the time causing them to burn up. My Nartron box was powering the glowplug relay all the time, and had several things connected to the output of the relay that should not have been, such as the #5 wire to the alternator. And several things that should have been driven by board logic were directly wired together, such as the starter connection. It appeared to be that way from the factory...it never could have worked right.
Just as a point or reference, I recently took off my intake manifold and injector lines to detail the motor, along with changing the fuel filter. I used tank pressure to force fuel out the vent fitting of the filter, used a small funnel to fill the rubber line going to the IP (everything very clean!) and then connected it quickly to minimize air getting in. Then with the lines loose at the injectors, it took 40 seconds of cranking (10 seconds 4 times, waited 10 minutes between) to get fuel at each injector. Then cranked with glowplugs disconnected until some smoke appeared, then connected glowplugs and it fired right up.