The fuel consumption in a modern truck is calculated by the engine management computer. With the use of sensor data an estimate of used fuel is calculated. In general the deviation between tanked liters and CANbus fuel consumption is between -2%..+2% .
• Tanked liters are never accurate as a full fill up can be -/+20 liters accurate.
• The tanked liters are volume based, every 18 degrees increase in Fuel temperature = 1% volume increase.
• Vehicle CANbus problems. Sensor Values are not correct on the Vehicle Direct CANbus.
• The diesel fuel density can vary between 835 - 845 gr/liter.
• Fuel usage in low-RPM ranges are less accurate then fuel usage at normal operation RPM ranges.
• Vehicle is “Chipped Tuned” in order to save Fuel or improve the vehicle engine power.
• Sometimes the internal parameters of the engine management calculations are incorrect, resulting in in-accuracy.
• Engines with +6 years running life have wear factors, not taken in consideration in the fuel calculations.