The Parts of a Fuel Injection System
The parts of a fuel injection system exist either to deliver the fuel to the injector(s), or to supply information that the control unit requires in order to provide the most efficient engine operation possible.
Fuel storage and delivery components include the fuel tank, pump, and lines. The fuel pump is capable of supplying up to sixty PSI of fuel pressure, so the fuel lines and connections are designed to withstand pressures almost double that.
Your car will have either two injectors, or one per cylinder, and sometimes one extra. In throttle body injected vehicles, there will be two injectors, and with port injection systems, there will be a single injector for each cylinder, plus sometimes an accelerator/cold start injector.
One way that injected fuel volume is controlled is by restricting the length of time that the injector is pulsed for. Metering fuel pressure to the injector is the other and is accomplished using a fuel pressure regulator, which can be pre-calibrated, vacuum- or electrically-controlled.
Most fuel injection systems have at least four sensors: the throttle position sensor uses a rheostat to determine how much acceleration you desire. The Mass Air Flow sensor determines how much air is entering the intake system. The oxygen sensors measures exhaust temperature, which is interpreted to determine whether the engine is running lean or rich. A sensor that determines crankshaft position tells the system which cylinder will fire next. This sensor is also required by the ignition system; on most cars, this is a crankshaft position sensor, a camshaft position sensor, or, on some cars, both.