Fuel Injection Systems: Notes

Overview 

There are 2 types of fuel injection systems, direct fuel injection and port fuel injection. The direct fuel injection system delivers fuel directly into the engine cylinder. The port fuel injection system delivers fuel into the intake manifold ports where the fuel is mixed with air and enters the engine cylinder through the intake valve.

On engines with dual fuel injection systems, both the direct fuel injection system and the port fuel injection system are used to deliver fuel to the engine. During heavy acceleration, or higher engine loads, the direct fuel injection system is used to deliver fuel to the engine. During idle, or low engine load conditions, the port fuel injection system is used to deliver fuel to the engine. Both fuel injection systems may not be active at the same time. The PCM will ignore any related fuel system sensor inputs, if either fuel injection system is inactive. Related fuel injector DTCs can only be set while the direct fuel injection system or the port fuel injection system is active. A scan tool may be used to activate either system to assist in isolating the fuel injector concerns.

For additional information on the direct fuel injectors, refer to Engine Control Components. 

For additional information on the fuel injectors, refer to Engine Control Components.