Why won't my '84 diesel buick start withought starting fluid?

I have a 19843 Buick lesabre 5.7l diesel. i have to use starting fluid to get it start after it has sat for a few hours but if i start it after its been running after just a little while it starts just fine?Why won't my '84 diesel buick start withought starting fluid?Could be the glow plugs aren't working but more likely it is due to low compression due to too much wear on the cylinder walls and piston rings. If it starts ok when it is still warm but fails after the engine cools down it is because metal expands and contracts with temp therefore the rings seal when warm but not enough when cold. It starts on starting fluid because it is so much more volitile than diesel fuel.Why won't my '84 diesel buick start withought starting fluid?You have to turn the key to the "run" position for about a minute, without starting the car. this allows the glow plugs to warm up then the vehicle will start. - and how did you get a car from the future?