Escort L4-116 1.9L SOHC HO (1989)
Fuel Pump Inertia Switch: Description and Operation
Central Fuel Injection - CFI
Typical Inertia Fuel Shut-Off Switch
The inertia switch is used to shut the fuel pump OFF in the event of a collision by opening the power circuit to the fuel pump, or the control circuit to the
fuel pump relay. The engine will quit running a few seconds after the fuel pump loses power. The inertia switch must then be manually reset before the
engine can be restarted.
The inertia switch consists of a steel ball held in place by a magnet. When a sharp impact occurs the ball breaks loose from the magnet, rolls up a
conical ramp and strikes a target plate, which opens the electrical contacts.