Engine Control Module: Description and Operation

ENGINE CONTROL SYSTEMS
The multiport Sequential Fuel Injection (SFI) system is classified as a multi-point, pulse time, mass airflow, sequential fuel injection system. It is used in the following engine applications:
- all 5.0L
- all 4.9L
- 5.8L under 8,500 lb. GVW
- California over 8,500 lb. GVW
- California under 14,000 lb. GVW

All other engine applications use the Multiport Fuel Injection (MFI) system, which is classified as a multi-point, pulse time, speed density, fuel injection system.

Typical Vehicle Emission Control Information (VECI) Decal:

NOTE: Before beginning diagnosis, it is important to determine if the vehicle utilizes the On Board Diagnostics I (OBDI) or the On Board Diagnostics II (OBDII) system. Consult the Vehicle Emission Control Information (VECI) decal for this information.

To maintain the required exhaust emission levels, the fuel metering system must be in proper operating condition and adjusted to the specifications listed on, for example, the VECI decal.

Additional engine performance checks are required to keep the exhaust emissions at the specified minimum pollutant level.

POWERTRAIN CONTROL MODULE
The Powertrain Control Module (PCM) receives inputs from various engine sensors to compute the required fuel flow rate necessary to maintain a proper air/fuel ratio throughout the entire engine operational range.

The PCM also determines and compensates the vehicle's uniqueness. The system will also compensate for changes in altitude (i.e., from sea level to mountains).

Depending on engine application, a vehicle will be equipped with the EEC-IV or -V system. The EEC-IV system uses a 60-pin PCM while the EEC-V system requires the 104-pin PCM.