3ltr diesel shutting down

iiI have a 1994  with the 3ltr diesel .you can drive for about 20 to25 klms and then the engine will shut down and when it does the glow plug light flashes on and off continualy and you can hear a clicking noise from injector pomp area .If you turn the key off and try to restart it ,it will start and stop straightaway and blow a heap of smoke,If you turn the key off and give it about 5 minuits it will go for about 2 to 3 klms and then stop again.Does anyone have any idea what this could be?????