Injection System

WARNING: This page is about a different car, the 2022 RAM ProMaster 3500, 2022 RAM ProMaster 2500, and 2022 RAM ProMaster 1500. However, it is still accessible from the selected car via links, so may be relevant.

All engines used in this vehicle have a sequential Multi-Port Electronic Fuel Injection (MPI) system. The MPI system is computer regulated and provides precise air/fuel ratios for all driving conditions. The Powertrain Control Module (PCM) operates the fuel injection system.

The PCM regulates:

Air/Fuel Ratio
Battery Charging
Cooling Fans
Emission Control Devices
Electronic Throttle Control
Idle Speed
Ignition Timing

Various sensors provide the inputs necessary for the PCM to correctly operate these systems. In addition to the sensors, various switches also provide inputs to the PCM.

The PCM can adapt its programming to meet changing operating conditions.

Fuel is injected into the intake port above the intake valve in precise metered amounts through electrically operated injectors. The PCM fires the injectors in a specific sequence. Under most operating conditions, the PCM maintains an air fuel ratio of 14.7 parts air to 1 part fuel (by weight) through constant adjustment of injector pulse width. Injector pulse width is the length of time the injector is open.

The PCM adjusts injector pulse width by opening and closing the ground path to the injector. Engine RPM (speed) and manifold absolute pressure (air density) are the primary inputs that determine injector pulse width.