Physical ethanol sensor speed?

[Marky Dissod]

Just guessing here but i would think that it would take a little but of time / few miles or so driving before the sensor could pick out the exact mixture given that the fuel that it’s trying to read is a liquid that’s already diluted with other grades of fuel in the tank.

It’s not like it’s trying to determine a total amount of fuel in the tank like how a float gauge would give,
it’s a specific amount of a grade of fuel it’s trying to determine.
I don’t think the reading would be instantaneous like an 02 sensor.

But this could be totally wrong, i almost feel bad posting this skimming thru some of the more knowledgeable replies.

It likely deduces the ethanol concentration after being given enough time.
It notices an O2 voltage, and makes an adjustment.
Before, when the pcm knew exactly what kind of fuel it was working with,
it understood exactly the magnitude of the effect it would have by making X amount of an adjustment.

But since it doesn't know the ethanol concentration of the fuel it's working with -
it only knows it recently refueled by more than 3 gallons, and that it should recalculate -
it eventually (re)learns the fuel that it's working with by making a fueling adjustment,
seeing how much that fueling adjustment affects things,
and the closer its adjustments meet its expectations, the better it knows what fuel it's working with.

 

[Fless]

From what I can tell, the physical sensors calculate the alcohol content using frequency, which jibes with the Tech 2 alcohol frequency info.

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