[j12piprius]

The mpg using EoffC on my trips has been much less than with leaving the engine on when coasting. For example, two previous 125 trips averaged (1) 54.0 mpg using EoffC all the way, then (2) 59.9 mpg using EonC, averaging about 55 mph. Care has been taken to shift at lower speeds, and to not lose momentum with shifting, so the continued poor EoffC result has been puzzling. My kill switch is connected to the fuel injectors.

Recently I've noticed that switching the injectors back on (with the engine off), drops .05 volts from the battery, thus 20 switches drops the battery from 12.8 to 11.8 volts. Perhaps this drop results in the alternator working harder while driving, uses more fuel, and causes the lower mpg.

My hypothesis is that EoffC is only useful below a certain break even point, depending on the aerodynamics of the car. For example, my car gets 30% better mileage using EoffC when averaging only 20 mph, but 10% worse mileage averaging 55 mph, with an estimated break even point of 40 mph. Better aerodynamics would raise the break even point higher.