Exam 30: Electronic Fuel Injection

In a GDI (gasoline direct injection)system, the tip of the injector is located ______.

____________________ systems inject fuel above the throttle plates.

What is meant by sequential firing of fuel injectors?

In closed loop, the PCM adjusts the pulse width according to inputs from a variety of sensors, but primarily the _____.

The throttle stop screw on modern throttle bodies is used to adjust the idle speed.

Typical fuel injector pulse widths range from _____ to _____ milliseconds.

Technician A says the computer uses the TP sensor and ECT sensor signals to determine the amount of air entering the engine in a speed-density system. Technician B says the computer uses the TP sensor and oxygen sensor signals to determine the amount of air entering the engine in a speed-density system. Who is correct?

Define fuel injection.

Technician A says when the ECT sensor detects low engine temperature, the PCM decreases the injection pulse width. Technician B says when the TP sensor detects a sudden increase in throttle angle, the PCM increases the injectors' pulse width. Who is correct?

Explain how the computer controls the air/fuel ratio on an EFI system during closed loop.

In ____________________ systems, the injectors are grouped together in pairs or groups, and these pairs or groups of injectors are turned on at the same time.

Fuel injector firing is being discussed. Technician A says SFI systems control each injector separately so that it fires just before the intake valve opens. Technician B says sequential injector firing is more accurate than multiport systems. Who is correct?

In a GDI system, the fuel is injected at pressures above ____________________ psi.

Bottom-feed injectors used in throttle body injection (TBI)systems are able to use fuel pressures as low as 10 psi.

A fuel injection system that uses a MAP sensor [manifold absolute pressure] to determine the amount of air entering the engine is called a _____-type injection system.

PFI systems use at least one injector at each cylinder.

If the throttle is held wide open while the engine is cranked over by the starter motor, the fuel management system will enter _____ mode.

The ____________________ in a PFI system controls the amount of air that enters the engine as well as the amount of vacuum in the intake manifold.

The longest injector pulse width occurs during ______.

The ____________________ receives signals from all the system sensors, processes them, and transmits programmed electrical pulses to the fuel injectors.