A tps doesn't work like that. The tps has an input reference voltage sent to it of 5 volts. This is the maximum it sends back to the ecu at wide open throttle. If it had a 12 volt input reference it could send a 12 volt maximum signal back. But wouldn't last very long. 5 volts seems to be the universal voltage adopted by all of the auto manufacturers. But getting back to your question. All setups work differently but mine seemed to mirror what I found in my research. 2 to 2.5 volts and pulsing the voltage yealds the most gas production. higher voltage only served to heat up the water in the electrolizer at a fast rate. This reduces the gas output. you are wasting electricity heating the water, not using it to split it.