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Fuel Filling is Not Detected
  • technical_consulting
  • fuel
  • fuel_fillings

Fuel fillings are displayed in reports when the data received from the tracker meets all the criteria for detecting fillings. However, in some cases, the Fuel Fillings table doesn’t display the results, although you know for sure that the fuel filling was performed, and the chart in the report shows a sharp increase in the Fuel level line. By following simple recommendations from this article, you can fix the situation and understand the logic of some fuel settings.

Possible causes and their elimination

Sometimes, it will be enough to follow only one recommendation from the list below to solve a problem. More often, you will have to follow several tips at once. But in some cases, you won’t be able to avoid detailed analysis of all fuel level sensor settings, as well as of the features of incoming messages and parameters.

At the same time, fixing the situation with the displaying of one filling often results in the emergence of other inconsistencies in fuel reports. That’s why there should be a comprehensive approach to the fuel data analysis, considering not one filling but several at a time.

1. Filling is ignored due to smoothing

Try to reduce the filtration level in the fuel level sensor settings.


The fuel level in the tank fluctuates due to engine operation, acceleration, braking, turning, road bumps, vehicle tilt, and so on.

The higher the filtration level, the stronger is the smoothing used to compensate for FLS readings fluctuations. The stronger the smoothing, the easier it is to analyze the processed data, but the more distorted the input information is. Thus, to obtain the needed accuracy, you should set the filtration level to the minimum required. If the filtration level is too high, the processed data may no longer contain the fuel level difference corresponding to the filling. In most cases, it’s not recommended to use a filtration level higher than 10.

Often, test fuel fillings are not displayed for this very reason: they are performed immediately after or before fuel draining, that’s why a short-term fuel level change is ignored due to smoothing. Actual fillings don’t imply the return of the fuel level to the previous state, so they will not be missed for the indicated reason.

You can also try enabling adaptive median filtration.

2. Filling is filtered by volume

Try to reduce the value of the Minimum fuel filling volume option in the fuel level sensor settings.


This option acts as a kind of coarse filter separating fillings and normal fuel level fluctuations, which will remain even despite the use of filtration. Consequently, you should choose the Minimum fuel filling volume in proportion to the value of these fluctuations that in some cases can even reach 20 liters or more.

If you set a too high Minimum fuel filling volume, the actual filling may disappear from the report results.

3. Filling takes place in motion

Adjust the Trip Detector settings by increasing the Min moving speed ​​if the speed is not related to the actual trip of the unit but is related to the error in the initial data. However, if the speed in such messages is comparable to the speed of actual trips (for example, more than 10 km/h), you can probably delete such messages, and to avoid similar situations in the future, you can try to filter them out. Please keep in mind that you will not be able to recover messages deleted manually or as a result of message validity filtration, so pay special attention to these steps.


Speed determined by the tracker and displayed in the monitoring system doesn’t always clearly indicate that the unit is moving. This happens due to the inaccuracy of satellite navigation systems (GPS, GLONASS, and so on). To determine the fact of driving, the Min moving speed is used, which defines the minimum threshold of the speed value recognized by the system as a movement.

In rare cases, speed value inaccuracy reaches large values, which can be associated with both the tracker quality and the environment (terrain, being in a building, the presence of large metal structures nearby, and so on). Some trackers can independently mark messages with inaccurate speed as invalid. However, using Messages validity filtration, you can find and filter out such invalid messages already in Wialon. This filtration applies only to messages that arrive on the server after enabling the appropriate settings, that’s why you’ll have to delete previous invalid messages manually.

Another method for solving a problem is to enable the Detect fuel filling only while stopped option and increase Timeout to detect final filling volume in the fuel level sensor settings.


Fuel level sensors may be inert, i.e., send data with time delays. For some FLS, this is a consequence of built-in filtration; in other cases, the delayed data arrival points at the need of FLS maintenance (for example, cleaning the drain hole).

None of the variants work

You are probably faced with a more complicated situation than those discussed above, and you should contact technical support via support@gurtam.com. Make sure to indicate in your email the exact unit name, the report template name for verification, the minimum time interval for verification (for example, not a month, but several days), and other essential details.

Oleg Zharkovsky,Customer Service Engineer

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