Another tip for cold weather starting is to cycle the glow plugs twice before trying to start. Turn the key to "on" until the glow plug light goes out, then turn it off for a minute, then back on until the light again goes out. Hold the gas pedal to the floor while cranking, then release it slowly when the engine has started. Even if everything is in optimum condition, in really cold weather (below about 20 degrees) most diesels simply won't start without a block heater that has been plugged in over night. Hope this helps.