motor churning starting

what is "churning"??

Cranking the motor but not firing

Should have said motor will turn but not run -switch ignition off then crank again and motor will start

Not exactly sure with the 3 lt TD
But the mighty 4.2, it's the glow plugs, and she runs as rough as guts once she fires.

Glow plug light/indicator goes out on the dash, then about 5 seconds later there is a clunk from under the bonnet, near the RHS bonnet hinge. That clunk is the actual glow plug relay/timer actuallt dropping out. It is only then I actually fire the motor.

I religiously do this routine, and in the winter I do this up to 3 times, depending on hoe cold it is.
New glow pluge lasted a total of one winter, before I had to go back to doing start up's like this. There maybe another problem associated with the startup, but this works, so I do it.

The other problem to look for, is there may well be air getting into your fuel line.
Check rubbers on fuel filter, check the fuel lines, and check the mount the fuel screws up to. Sometimes they can crack, and let air in.

Cheers
Bucky