FERIC (Forest Engineering Research Institute of Canada – a division of FP Innovations) has conducted research that evaluated the accuracy and precision of truck Engine Control Modules (EMC) in determining fuel consumption.
The abstract on the FERIC website indicates that various comprehensive tests were carried out to determine the accuracy of these engine computer systems. It goes on to say that the data precision and accuracy varied between engine manufacturers as well as between specific models of a single engine manufacturer. A long term average of the fuel consumption data produced was more accurate than short term readings. Therefore, one should be wary of using ECM data alone for measuring short term fuel consumption, and additional methods of measuring fuel consumption should be used, such as specific truck fuel use with the actual kilometres travelled. Source: www.feric.ca