Start -up problems with a 400 SDI rover

Hello foros my problem is the following I have a 400 diesel rover with 12 years and 190000km the truth is that it has never given me problems and now suddenly when I stop the car and it is stopped five hours forward I have problems when starting it does not matter if it is day or at night either that it does not make cold or heat and when I try to tear it to the second or third time that I turn the key I have to step on the accelerator then then it starts then it goes on and Without problems until I return it has stopped 6 or7 hours. thank you.

I have had this problem with a 220 DSI and it was the point of the pump distribution strap.

Change preheating spark plugs