First, you should check your system to see that it is operating properly. Then, after you have determined that it does, then you can experiment with the system.

Check visually that the system functions mechanically without obstructions: check for bubbling level, loose connections, possible leaks or breaks, blocked or dented vacuum hoses, etc.

One major problem I have identified is that of clogged hoses and passages. Sometimes baking soda builds up in narrow passages such as the universal vacuum-T, the output check valve (mainly the one going to the intake manifold), and in some cases even the vacuum port going to the intake manifold (especially if its inner diameter is very small). These clogs reduce mileage considerably since they impede the flow of HHO to the engine.

Blockage looks like a white stone. Yet it is VERY EASY to remove because it is very soft. Flush the clogged passage, valve or hose with tap water. No detergent necessary. DO NOT PUSH HIGH PRESSURE AIR through the check valve since this may bust the delicate membrane. Some water and a gentle mouth air blow will clean it in no time.

The secondary source of mileage problems may be the computer, especially if it’s a fuel injected engine of newer models. With any H2O (vaporizer) or HHO unit (electrolyzer) installed, the car’s computer may sense more oxygen in the exhaust pipe. It then considers the fuel mixture to be too lean – and adds more gasoline - unnecessarily.

What really matters is the SYSTEM approach. I had the same problem as you are having now, and I was frustrated when Dennis Lee and others were bragging about doubling mileages.

So I did a thorough research and found out WHAT system is needed. There are two sectors - 1995 and older - and 1996 and newer - let me address the newer ones.

The HHO is combustible alright, and will ALWAYS improve fuel combustion and thermal efficiency. But DEPENDING ON THE COMPUTER software, the extra oxygen detected by the O2 sensor causes the mixture to be richer than it was before. The result? Same mileage or slightly worse. Not true for all cars. Two Jaguars JX-6 (or is it XJ-6, I can never tell) responded well without any addition. Diesels as well do not suffer from this problem.

Now you need to lean the mixture, but you have to LEAN it by force. The MAP sensor (or MAF sensor) is a good choice for a point of control because (1) it is cheaper to control, and (2) is you now open the loop of the upstream O2 sensor (the one closer to the engine) by simply disconnecting its plug, now the MAP/MAF sensor becomes the major input and the computer has no option but to take whatever you feed it. You attenuate the signal by variable resistor, and you can now dial any MPG (to a point of course) on the ScanGauge, almost as if you were tuning the radio.

Amazing to watch it on the road. Even before you hit the road: idle the engine and tune the ScanGauge to show GPH (gallons per hour) then put some load on the engine by turning the a/c full blast. Tune the MAP signal with the MAP Sensor Enhancer knob, and watch your GPH numbers cut in half or in some cases even a bit more.

Now a very similar thing will happen on the road, and you may find the knob reaching optimal operation on the road almost at the same spot as you did in parking.

I wouldn't put the HHO before the air filter. Put it after, and ALSO into the intake manifold. This is important because vacuum enhances HHO production. My books and DVD's show how to double-connect, with hi-flow check valves preventing back pressures between the two lines. They also explain and show in great detail how to solve the computer problem described above. Read or watch these chapters several times for full understanding - results are sure to come if you follow all the guidelines and experiment with all possible sensors and methods.

Experimenting with one vehicle in length, solving all its problems and fine-tuning it to the very maximum of its potential mileage, is specially beneficial and profitable IF YOU ARE GOING TO USE THE RESULTING KNOWLEDGE IN A FLEET OF SIMILAR MODELS. Every dollar you save, every gain you get on that one car or truck or boat or train, will keep multiplying itself for years to come.