Calculated Fuel Economy

Not a problem to be fixed, but I wondered if anyone knew how the average fuel consumption is calculated by the ECU and whether or not overfuelling injectors would skew the figures to make them seem better than the actual consumption?

For example, if an injector is leaking, the unmetered fuel would probably not be part of the calculation and would account for a discrepancy in calculated vs real mpg.

If this is correct, differences in calculated vs actual consumption, might be a way to determine injector issues early on.

Just a thought…

It is calculated using the known mass per CC per millisecond of duration so unmeasured flow would corrupt the figures.

Thank you.
That would make sense and possibly explain why some cars trip computers seem accurate and others not so.