Bro as per my humble knowledge, if your glow plugs are working perfectly and your engine does not start when cold, the only problem is engine compression. No amount of pump, injectors, oil, coolant servicing etc will rectify this problem because your engine is weak. At 3lac km, a mitsubishi diesel has almost certainly lost compression which is why its giving this problem.
Unless you get it rebuilt, you will be wasting time and money on everything else that you do.
So please also consider this dimension of your problem.
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