wont start on a cold crank if it has stood for more than 6 hours replaced battery replaced fuel filter replaced fuel valve on fuel filter replaced glow plug relay replaced glow plugs had timming checked and fuel pump been on computer shows no faults got to use easy start start then it is fine for rest of the day this problem just occured about two months ago HELP also discovered it is worse when damp or wet

I see that you have changed the glow plugs but are you sure that they are receiving a voltage and are working,you cant realy test the fuel pump with the diagnostic tester you have to check the output flow against the spec.

Is the coolant temp sensor working as this determines the glow plug timing and operation. Is the cranking speed of the starter motor sufficient on a cold engine.