Fuel Injector: Description and Operation

Typical Fuel Injector:

PURPOSE
Electrically operated valves that permit precise metering of fuel into the intake system.

LOCATION
On intake manifold near cylinder head.

OPERATION
Fuel injectors are electrically operated solenoid valves that open when energized. Injectors receive battery power from the main relay when the ignition is at either "START" or "RUN" position. They are energized when the ECU completes the circuit to ground. Injection timing and duration are determined by the ECU. Injectors are energized either simultaneously once each crankshaft revolution (during cranking and cold engine operation), or in pairs (normal warm engine operation).

CONSTRUCTION
Constructed of stainless steel and high density plastic to resist corrosion. They consist of a fuel inlet with filter screen, an electrical solenoid and connector, and a pintle valve and nozzle. Injectors are held in place by the fuel rail and sealed by an O-ring and insulator.