Abstract: A fuel injection shutdown system for a fuel injected internal combustion engine having mechanical fuel injectors with a return spring and lifter bodies slidably disposed in lifter guides comprises a slot formed in the lifter guides to receive a hydraulic cartridge and a slot in the lifter bodies which registers with the slots in the lifter guides, but are longer, the hydraulic cartridge extends into the slots in the lifter bodies, as the lifter bodies are reciprocated by an injection cam and the hydraulic cartridge does not contact the slots in the lifter bodies and the hydraulic cartridges have a stop pin slidably disposed therein and have a hydraulic duct which when filled with pressurized hydraulic fluid causes the stop pin to extend from the hydraulic cartridge contact the top of the slot in the lifter body and hold the lifter body off the cam preventing the fuel injectors from injecting fuel into the engine in two engine revolutions and stopping the engine to prevent harm to the engine.