My L175 fails to start. It turns over fine. Glow plugs get hot. Fuel lines are clear. Just won't run. I don't know how to test the injectors or valves.
Think of going to your doctor..... you have a problem.... to get a diagnosis you have to provide details and answer questions.
What is your history with this tractor?
Did this condition develop slowly or suddenly?
Did this problem start after some work being done.
How do you know the glow plugs get red hot? You saw them this way? They should never be powered up when not in screwed in contact with the head or a big heat sink like a vice.
Did you run out of fuel?
Dave