To really understand exactly what the MAP Sensor Enhancer do and why, requires an understanding of the on board computer system of a vehicle. (MAP Sensor stands for Manifold Absolute Pressure Sensor and is explained further down in more detail).

The reason for an “enhancer” for the MAP Sensor is because, when any fuel saving device or product is added to the vehicle, the pre-programmed computer settings will attempt to neutralize the effect of these devices or products. This will be explained in more detail further down. Without this enhancer most of the benefits of a water fuel system is neutralized in cars built after 1996. Cars built pre 1996 may not need it.

Following is a quite technical description but I think we need to realize some things:

• If you are so inclined, the MAP Sensor Enhancer is a very simple device the details of how to make is fully covered in the Water4Gas product manuals.
  
• However on the website there is a database of manufacturers and installers, for this device and complete systems, around the world. (The route I am inclined to take!) This system really has huge benefits in terms of saving gas (we talk up to 50%), it is beneficial for the car (car runs smoother) and it benefits the environment (emissions much less harmful).
• So while the hardcore engineering types can read the rest of the article the rest of us can simply click this banner and have a look at the full description of the product!

There are lots of questions about the MAP Sensor Enhancer posted all around various sites. With this article my aim is firstly to define the acronyms and terms used, explain what it is and the reason for it’s existence and then to answer some of the questions.

For a better understanding of how things fit together lets look at some of the components that play a role and what they do. Lets start by defining some terms.

OBD means On Board Diagnostics – basically the engine computer system and is a set of performance sensors that are mandatory on all cars since 1996 in the US.

OBD-I is pre-1996. Now we have OBD-II.

ECU or Environmental Control Unit. Sometimes we are simply using the word computer as a generic term. Some cars have more than one computer and the ECU is the component tasked with fuel usage, emissions etc. It aims to maintain an air to fuel mixture of “proper” proportions. According to automotive conventional wisdom it should be 14.7:1. A car can drive just as nicely on 25:1 if you were to design it in a slightly different way, It’s so-called “Stoichiometric” balance would now be 25:1 for example. (a big word that simply means “balance of ingredients”).

A Lean or Rich Mixture are terms used to describe when the air to fuel mixture differs from the “ideal” of 14.7:1. A very rich mixture would be something like 10:1 where less air per unit of fuel is present and a very lean mixture would be something like 18:1 where more air per unit of fuel is present.

EFIE stands for Electronic Fuel Injection Enhancer. An EFIE, is not a fuel saving device on it’s own. If all you did was add an EFIE to your car with no other change such as a HHO Maker you probably would actually lose MPG. You might even damage your car by making the mixture too lean and overheating the valves. The EFIE was designed to make the car run according to original manufacturers specifications after for instance adding hydrogen and oxygen to the air intake. In this case the hydrogen and oxygen burns to produce water and a very lean mixture does not overheat the valves.

The Mass Air Flow (MAF) sensor helps the computer to calculate the flow and mass of the air entering the engine. It does that by measuring the cooling effect of air flow over a heated wire element. The electronic circuit inside the sensor attempts to keep the sensor at a fixed temperature. When it is cooled more by an increased air flow, more current is needed to maintain a constant temperature. The increase in current is converted into a signal and that signal goes to the computer. During low air flow rates, such as at engine idle, the MAF sensor produces a lower frequency signal. During high air flow rates, such as at wide open throttle-road load, the MAF sensor increases the frequency. The control module then converts these frequencies into their corresponding Grams-Per-Second values.

O2 Sensor = Oxygen sensor, measures the amount of oxygen present in a liquid or gas. Inserted in the exhaust system of modern vehicles they measure the remaining oxygen left in the exhaust fumes after combustion.

The MAP or Manifold Absolute Pressure Sensor is a small but expensive device installed on your intake manifold, or installed on the firewall and connected to the manifold with a thin hose. It has 5 Volts or 12 Volts coming in, and it simply measures the vacuum in the manifold and attenuates (reduces, weakens) this incoming voltage by a certain factor In other words it reduces the supply voltage in accordance with the vacuum in the engine by 15% to 60% (depending on the car’s design these numbers will vary), and this signal is then sent back to the car’s computer. A higher output voltage means lower engine vacuum, which is then calculated as “more fuel is needed”. Lower output signal indicates higher engine vacuum, which requires less fuel. It’s not just fuel control though. The MAP sensor signal gives the computer a dynamic indication of engine load. The computer then uses this data to control not only fuel injection, but also gear shift and cylinder ignition timing. In some cases it is even used to calculate changes in barometric pressure, to automatically adjust for different altitudes.

The MAP Sensor Enhancer simply takes this already attenuated (reduced, weakened) signal – and attenuates it further. Too much attenuation kills the engine, it will simply shut off. Yet if you control it correctly you can lean down the mixture from the stoichiometric (factory set “balance of ingredients”) of 14.7:1 (14.7 parts of air to 1 part gasoline) – down to 20:1, maybe even 50:1 or 100:1. This device is totally passive and will work just the same if the incoming signal is 12 volts, 5 volts, or whatever comes on the line. The diagram here is the SIMPLEST way of doing this. The line from the sensor to the ECU is cut, and you place a potentiometer on the line as shown. This unit adjusts voltage in the minutest level to trick your cars ECU into thinking more gas is being burned while in fact you are replacing it with hydrogen and save gas. The unit is usually installed so that the driver have access to it while driving and adjusting the potentiometer is described fully in the Water4Gas manuals.

Remember also that air changes according to different conditions and adjustments for that should be made as well. Cold, warm, hot or rain days will react differently. Air density in HHO fuel enhancement really does matter and the enhancer makes tuning easier and on the fly.

This technology SHOULD be available on all cars. Just because it isn’t doesn’t mean its a hoax. The auto industry is not only in the business of selling cars, but also infrastructure. Selling service, fuel, and of course a new car every few years or so. They’re completely resistant to innovation unless they have absolutely no choice.

It should now be reasonably clear why and when an enhancer is needed. There are differences in the design depending on whether the vehicle employs a MAP or a MAF sensor (only one of the two is used in a particular vehicle) and whether additional oxygen sensors are used in the exhaust.

To Locate your MAF or MAP sensor follow these directions. MAF (Mass Air Flow) sensors are almost always mounted on the air intake of the engine between the throttle plate (where the throttle position sensor and throttle cable is located) and after the air filter. If you do not have a MAF sensor, then locate your MAP (Manifold Absolute Pressure) Sensor. It is installed on your intake manifold, or installed on the firewall and connected to the manifold with a thin hose.

Once you have located your sensor, you will need to identify the wire carrying the sensor signal back to the your car’s computer. With your ground lead of a Voltage Meter grounded, start the engine and probe through the plastic wire insulation of the sensor’s wiring with the positive lead to find the wire with 0 to 5 volts. Once you have located this wire, rev the engine to see if the voltage changes drastically. The wire that reacts up and down in voltage to the engine revving will be the one you will need. The power into the MAP sensor voltage is constant and that’s it except for the ground. It’s rather simple once the proper wire is found.

An internet resource that might be useful is www.rockauto.com where you might be able to lookup the info for your car.

Here is another trick, simply call an auto parts store and ask them if they stock a MAP sensor for your year and model. They’ll either give you a price for one, or tell you your car doesn’t have one!

These descriptions are given to enable you to apply the correct circuit for each sensor. There are also rare instances where the MAP sensor works with frequencies. If this is the case, employ the Oxygen Sensor device called EFIE from http://www.eagle-research.com/products/pfuels.html.

All this appears to be a lot of trouble but when you employ some form of water fuel technology you have taken a big step to reduce your dependence on oil based fuels and the savings can be really significant and worthwhile.

I hope that this clarifies a few things and is of use to you. Much more detail is available at Water4Gas.