Nov 24 (Reuters) - Ford Motor Co (F.N) is recalling 634,000 sport utility vehicles (SUVs) worldwide over fire risks from possible cracked fuel injectors and will urge owners to have their cars inspected, it said on Thursday.Ford said when engines in the SUVs covered by the latest recall are operating, a cracked fuel injector could cause fuel or fuel vapor to accumulate near hot surfaces, potentially resulting in fire under the hood.Once repairs are available dealers will update vehicle software to detect whether a fuel injector is cracked and provide a dashboard message to alert drivers."If a pressure drop in the fuel rail is detected, engine power will automatically be reduced to minimize any risk, while also allowing customers to drive to a safe location and stop the vehicle and arrange for service," Ford added.Dealers will also install a tube draining fuel from the cylinder head and away from hot surfaces and check for excessive fuel odor near the top of the engine."