Why the diesel pump for nissan hardbody is not getting the power

I would look at all fuel pipes and fittings. If the engine and pump are in time with each other that would be about the only explanation, well either that you are loosing prime in the fuel system or you are low on compression.

run fault codes first
quick start in a diesel is a sure fire way of destroying the engine and voiding any warranty

Could be the heating plugs. The diesel does not get heated enough?!

I have Nissan hardbody diesel 16 vengine it cranks quickly but doesn't want to start

It could be, but if you haven't replaced the fuel filter for awhile, I'd start there, remember to fill the new filter with clean diesel fuel before installing, it will make the engine far easier to start. Good luck.

DIESELS DO NOT START FOR ONLY 3 REASONS.. 1. not getting fuel. 2. Glow plugs not working.. 3 major engine damage
1. air in system.. like you ran out of fuel, Fuel filter clogged, lift pump not working, no fuel in tank, Bad fuel. .. 2. glow plugs..check the wire at the glow plug to see if it has power. If it does not check the relay and fuse. glow plugs usually do not all go bad at one time. 3. major engine damage.. you would normally notice this by the noise the engine makes or it would not turn over..

is this a petrol or a diesel ??

surely your vehicle fitted with Cam sensor and Crank sensor. Try to check whether the fault is onto one of them.

Problem with 1998 Honda Civic Nissan hardbody 3.0td loses power and dtc code 42 must be old nissan as 98 civics use OBD2 codes.
what year, Nissan, and is this Turbo Diesel, if yes, get the FSM
its complex.ever heard of that , FSM
the factory service manual, all cars have it.

the fuel pick-up in the tank has a sock on it to filter out any large debris to keep it from damaging the fuel pump, that sock can become clogged and prevent adequate amounts of fuel from getting to the pump thereby starving the pump