The HHO generator uses low DC voltage to produce Hydrogen and Oxygen from water.
Fresh water isn't the best conductor of electricity so an electrolyte of some sort is usually added to the water.
A safety tip: This was probably included with your unit, but it doesn't hurt to cover it again.
- Wear safety glasses, good ones.
- Dont smoke or have any ignition source while checking the unit. HHO is produced at the optimum ratio for combustion, and by that I mean COMBUSTION. This is the same fuel in the same ratio in that big orange tank the space shuttle rides on. The slightest leak can be dangerous. Be aware of this. Ok?
A side effect of these units is they produce heat. The water gets pretty hot, not boiling, but hot. That would be a way to see if its working.
You haven't described the unit, volume of water and electrolyte used. That would be helpful.
As a rule, if the plates are covered in water, if the electrolyte has been introduced, if it has power then it's working and you won't notice any difference at all.
Unless the unit you got is the super deluxe multi-cell model, the volume of HHO produced per minute is only a small percentage of what the engine is sucking in. It's not going to supercharge your engine. It will however enhance the combustion of the gasoline, making it burn more efficiently while adding some combustion of its own.
Hopefully you kept track of your mileage before instrallation. Keep keeping track of your mileage and compare notes. That's when you'll notice the difference.
That difference will depend on the volume of HHO produced. That depends on the electrolytic agent, volume and temperature of the water.
I hope this helped somewhat