Roland;
So is your constant attention with your fuel pump controls due to you trying to get max MPG?
In other words if you were content with 25-40% MPG improvement, could the fuel pump mod be a hands off/set it & forget it mod ?
Most of the attention is due to having to alter the voltage. Uphill or passing would need an increase to 6.5 to 7.8 volts. Some level or near level inclines could use 4.55 volts(i found this to be the least i could keep the car running with minimum load), downhill I could shut the pump off. The car would idle even with using the cruise control at 70 mph(my theory on this is that the transmission convertor was assisting the engine by the stall speed). As the car started to take on a load it would shutter and near stall(so back to 4.55 volts). When i was driving on city highways where there were traffic lights i had to stay around 9.7 to take off from still. One hill on the interstate i had to go to a full voltage around 13.7-14.3 volts(system charging). With my scanner hooked up i could see when i was charging or not, voltage would vary slightly. As well, watching the o2 sensors was incredible! To see bank 1 running at 0 to 40 ppm and bank 2 at flat 0 ppm, SWEET. THIS WAS WITH NO EFIE OR PWM !!!! True o2 voltage and measurements.
To answer your question; Hands off mod. Maybe, if a tps-pwm was integrated to adapt to load demand. Basically you need the fuel pump to respond to demand but only when the load is TRULY pulling down on the engine. A lot of the fuel lost is when you apply the gas pedal to accelerate, so cut back on that waste.
Its done right or its not done !
Hail HHO.