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Old 11th January 2022, 11:20   #6
T-Cut
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Just to compound the wandering fuel gauge issue, worn rheostat 'windings' is clearly a big part of it, but there appears to be more subtle effects related to the state of the engine at the time.

For example, in 2014 BigRuss noted:

The fuel gauge and range on the message centre don't give an accurate reading until the engine temperature increases and the temp gauge reaches the 9 o'clock position. Don't ask for an accurate explanation, but my guess is the gauges are stabilised with regulator circuit. For those that don't believe me, give it a try. Look at the range from cold and again when warm. Applies to both petrol and diesel models.

My thought on this is that the current/instantaneous fuel consumption data is used to calculate range (it's all there is to go on). As the engine warms up, the range is rationalised to a more 'normal' consumption figure. However, this begs the question as to how consumption rate is calculated.


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