The Hull Truth - Boating and Fishing Forum - View Single Post - Managing fuel quantity?
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Old 12-09-2017, 07:23 AM
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Hmmmm ...

FWP - I thought measurement was based on the amount of air being sucked past the MAF, and then the fuel usage extrapolated from the fuel injected data table ... my understanding is that the airflow sensor (MAF) is extremely accurate, so, even though the fuel usage is related, it isn't actually measured.

In summary, then:
- readout on the "gas gauge" whether analog or digital is pretty much a resistance based summary based on a float or liquid level in the tank with commensurate errors based on tank size estimates, float or resistance errors, length of the bar measuring resistance, etc.
- readout of fuel used (or remaining as computed by the MFD) on from the engine is based on much more accurate process of measuring the actual amount of fuel (or, air and extrapolating fuel) used by the engine, but knowing the amount remaining does require resetting the MFD or gauges each fill up to full (Marshfly's experience is pretty typical and reported widely)

Both sources is a good idea ...however, to me it makes sense to hide the resistance reading gauge because it is now more of a backup - with much lower accuracy - ASSUMING the gauges/MFD are reset each fill up.