I got traded a 4010 diesel tractor went to look at it cranked right up had not just been running I felt of the block and oil and the muffler. Went back several hours later to pick it up it cranked right up. Got it home it sat on my trailer over night went to it the next morning and now nothing it turns over great but will not start. I gave it a shot of starting fluid and it did not even fire . There is no air in the system i get diesel out at every injector. Plenty of diesel in it. Why will it not start back up. Why will it not fire on starting fluid I sprayed it right into the intake.It does not even act like I am even spraying any in there. What could have happened .