HHO Car Conversion Kits

Another consideration, if you are planning to run hho, is an EFIE (electronic fuel injection enhancer). This device compensates for the added oxygen that will be in your mixture along with the hydrogen. In older vehicles, only the upstream sensors (before the catalytic converter) were used in a/f ratio calculations. Since around the year 2000, more car manufacturers are using the downstream sensors as well and not all are documented. Some are also using 4 and 5 wires and the whole thing is getting rather complicated. Read more