RP 344A - Understanding Engine ECM Data: Introduction

To understand electronic engine data, fleet managers must know how to compare data from all the various engines in their fleet. This requires understanding the differences between:

• the same models from the same manufacturer.
• different models from the same manufacturer.
• different models from different manufacturers.

Fleet managers must understand that modifying the electronic parameters under their control creates variables in the data stored in the engine ECM. Until ECM data standards are developed by TMC or SAE International, fleet managers may need to develop their own data standards when making engine comparisons.

Some of the reasons for data variability are:

• fleet parameter settings for the same engines are not identical.
• differences among engine manufacturers.
• all data analysis software programs don't analyze data the same way.

These can yield inaccurate comparisons between various vehicles in the fleet, or between two or more different fleets of vehicles.