I think you need to provide a little more information. Is/Are the starting battery/batteries charged? What happens when you turn the key/press the starter button? Is there some way to try turning the engine
over by hand? (might not be possible with a diesel) What is the history
of the engine? Was it running yesterday/a week ago/a year ago/Longer? I am not a diesel
guy so I won't be any help. Is the oil
black or some other color?