the machine is starting randomly when it wants too, then when it won't start it will just crank but won't fire. There is no power at the ECM. A Komatsu mechanic plugged into it and said everything checks out right. He spent the whole day working on it but couldn't figure it out. He switched a couple relays around but it didn't work. Also, every time the machine shut down, the primary filter happened to be half full, but there is no blockage down to the tank. Also, the same issue happened about a month ago, and when I went into work the next day it started and ran no problem, now a month later, it happened again but it will not run. Any advice would be helpful! Thanks!
Fuel system seems to be the first thing to check. Does this machine have the Komatsu engine or the Cummins clone? How many hours and what type of fuel injection? Injection pump or common rail? There will be a fuel strainer either in the end of a banjo bolt or a separate can with a bolt head on top. There will be seals of some type again either on the banjo bolt or the strainer can. If it has the Cummins engine there may be an in line strainer that looks like a gas filter you find in pre-emission gas engine lines. It may have one of those paper filters instead. Don't replace it with one from the auto parts store. Get a new one from the dealer.