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Electronic Fuel Injection Enhancer


So, you are thinking of using Hydrogen and Oxygen as an additive to your gasoline engine, and you are wondering if you need to invest in an EFIE device. That is not an easy question to answer.

In the past, fuel savers would not work when applied to fuel systems that use oxygen sensor feedback circuits. These systems were designed to prevent efficient combustion, by lowering and controlling the air mixture of the engine from 14.7 parts to 14.5 parts of air for each part of fuel! This was done to reduce Carbon Monoxide and NOX emissions in the engines exhaust, and to make your engine use more gas. The EPA then made auto manufacturers add expensive Catalytic Converters to the exhaust systems in order to get rid of the unburned fuel. To date, this is one of the biggest Scams ever pulled on the public. We fell for it, hook, line, and sinker. To beat all, it is computer controlled. If enough hydrocarbons are not measured in the exhaust, the computer sends more gasoline. This is the number one reason why most Fuel Saving Devices Do Not Work.

Increasing the combustion efficiency of the engine changes the percentage of oxygen in the exhaust because the engine uses less fuel for the same volume of air and the engine produces less carbon monoxide and oxides of Nitrogen. Oh, we can't have that (so says the EPA).

The increased oxygen content in the exhaust is read by the computer to be a lean mixture in the engine. As a result, the computer then adds extra fuel to bring the pollution back to normal. In other words, when the computer sees extra oxygen in the exhaust, it sends enough fuel to maintain a 14.5 parts air to 1 part fuel ratio. When the computer sees less oxygen in the exhaust, it backs off on the fuel to maintain a 14.5 to 1 fuel ratio. The EFIE's function is to modify the oxygen sensor's output-signal to the computer - by adding a floating voltage; so the computer will not see the extra oxygen.

If you plan on using Hydrogen and Oxygen as an additive, one way or another, the air fuel ration will have to be dealt with, if you want better fuel mileage. Hydrogen as an additive works. Oxygen as an additive works. They both provide better, more complete, combustion of the fuel. They both decrease harmful exhaust emissions. Period. It is a proven fact. It is the computer controlled Emissions Control System that reverses the positive benefits of HHO.

The EPA has been slowly passing tamper laws. It is unlawful to tamper with the Emission Control Sensors. These laws are going to be enforced, starting January 1, 2011. But there are no laws against reprogramming an Emissions Control System as long as the EPA standards are met or improved. That is the reason I chose the Volo Chip for my Ford modification. The chip replaces the ECM settings, in order to change and maintain better Air Fuel mixtures, based on driving conditions.  If you have a 1996 through 2009 vehicle with an OBD-2 Emissions Control System, then the Volo may be good choice for a lot of vehicles. I say may, because it is turning out that it is not the solution for a lot of vehicles. It falls short. The ECM works around it somehow.

If your vehicle is year 1987 through 1995, you probably have an OBD-1 Emissions Control System. OBD-1 systems usually need an EFIE; but not always. Some respond by injecting the HHO in front of the MAF sensor, so that the HHO must pass through the MAF sensor (if they have a MAF). Some of these vehicles accept HHO without any changes, just by resetting the computer; most do not. Reset the computer by disconnecting the battery for a few minutes. It causes the computer to relearn the fuel mixture.

  Which EFIE do I need?

  Sensor Request Form (find out what sensors you have and what Type they are)

  About Oxygen Sensors

  Oxygen Sensors, How to Diagnose and Replace

  OBD1 Vehicles, pre- 1996

  HHO Shortcuts



5 Types of Oxygen Sensors


Unheated Thimble-type O2 Sensors (LS)
Bosch introduced this design in 1976 for feedback fuel control on automotive engines. The zirconia ceramic "thimble" is encased in a protective tube which extends into the exhaust manifold. Slots in the protective tube allow hot exhaust gases to reach the thimble. Reference outside air for the interior of the thimble comes from a hole in the sensor shell, or through the wiring connector. Unheated O2 sensors rely only on the heat of the exhaust gases to reach operating temperature, therefore they might cool off while the engine is idling and revert back to a fixed air/fuel ratio setting. This type of sensor generally has a single wire connector, though some have two.

Heated Thimble-type O2 Sensors (LSH)
Introduced by Bosch in 1982, this sensor adds a heater element to the original design so that the sensor achieves operating temperature in 30-60 seconds, instead of being heated by exhaust gases. It has a separate electric circuit for the heater, so look for 3 or 4 wire connectors to distinguish this unit. The heater reduces cold start emissions, as well as prevents the sensor from cooling off at idle.

Heated Titania-type O2 Sensors
Titania sensors use a different type of ceramic and instead of generating a voltage signal that changes with the air/fuel ratio, the sensor's electrical resistance changes. The resistance is less than 1000 ohms when the air/fuel ratio is rich, and more than 20,000 ohms when the air/fuel ratio is lean. The ECU provides a base reference voltage and then monitors the sensor return voltage as the sensor's resistance changes. Titania O2 sensors are used on less than 1% of O2 sensor-equipped vehicles:

  • 86-'93 Nissan 3.0L trucks

  • '91-'94 Nissan 3.0L Maxima, 2.0L Sentra

  • '87-'90 Jeep Cherokee, Wrangler, and Eagle Summit

Heated Planar-type O2 Sensors (LSF)
Introduced by Bosch in 1997, this O2 sensors uses a laminated flat strip of conductive ceramic, electrodes, insulation, and heater. This sensor is smaller and lighter, and more difficult to contaminate. The new heater uses less electricity and brings the sensor to the proper temperature in 10 seconds. Outside reference air is supplied by a small port in the center of the ceramic strip where the 4 electrical wires connect. By model year 2004, planar O2 sensors are expected to account for 30% of all O2 sensor applications and by 2008, for up to 75%. The following list shows the inclusion of more and more models:

  • 1998: VW 2.0L New Beetle

  • 1999: Cadillac Catera, Saturn 3.0L LS, VW 2.0L Jetta

  • 2000: All Audis exc. A4 1.8L turbo and A6 2.8L; California Dodge 2.0L Neon; Ford 4.0L and 5.0L Explorer; Ford 2.5L LEV Ranger; Ford 3.8L Windstar; MBZ 3.2L ML320 and 4.3L ML430; Mercury 4.0L & 5.0L Mountaineer; Saab 2.0L & 2.3L; and all VW and Volvo models

  • 2001: Porsche 911 3.6L Turbo; all MBZ models exc. SL500 and SL600

  • 2002: All Audis, All Dodge Neons, all Ford F-Series trucks (4.2L, 4.6L, 5.4L), all Ford Ranger trucks, Mazda B-Series pickups (2.5L, 3.0L & 4.0L), all MBZ models and Saturn 3.0L SUV

Heated Wide-Band O2 Sensors (LSU) (from the November 2001 Bosch Reporter)
The newest O2 sensor technology from Bosch builds upon the planar design and adds the ability to actually measure the air/fuel ratio directly for the first time. Instead of switching back and forth like all previous sensor designs, the new wide-band O2 sensor produces a signal that is directly proportional to the air/fuel ratio.

The wide-band sensor uses a "dual sensing element" that combines the Nernst effect cell in the planar design with an additional "oxygen pump" layer and "diffusion gap" on the same strip of ceramic. The result is a sensor element that can precisely measure air/fuel ratios from very rich (10:1) to extremely lean (straight air). This allows the engine computer to use an entirely different operating strategy to control the air/fuel ratio. Instead of switching the air/fuel ratio back and forth from rich to lean to create an average balanced mixture, it can simply add or subtract fuel as needed to maintain a steady ratio of 14.7:1.

Like a zirconia thimble or planar-type sensor, the wide-band sensor produces a low-voltage signal when the air/fuel ratio goes lean, and a high-voltage signal when the mixture is rich. But instead of switching abruptly, it produces a gradual change in the voltage that increases or decreases in proportion to the relative richness or leanness of the air/fuel ratio. So, at a perfectly balanced air/fuel ratio or 14.7:1, a wide-band O2 sensor will produce a steady 450 mv. If the mixture goes a little richer or a little leaner, the sensor's output voltage will only change a small amount instead of rising or dropping dramatically.

Another difference in the wide-band O2 sensor is the heater circuit. Like a planar sensor, it is printed on the ceramic strip. But the heater circuit is pulse-width modulated to maintain a consistent operating temperature of 1292 to 1472 degrees F. the sensor takes about 20 seconds to reach operating temperature.

Reference: http://tayloredge.com/reference/Science/oxygensensor2.pdf

Note:  There are two types of narrowband sensors - Zirconia and Titania. Titania is used in Jeeps and off-road vehicles, especially. Please read this link to understand the difference  http://www.ngk.com/sparkplug411.asp?kw=Titania&mfid=1


Bosch Wideband Oxygen Sensors Precisely Measure Air/Fuel Ratios


Wideband Oxygen Sensors
 As engine management and on-board diagnostic systems continue to evolve, so too do the oxygen sensors that monitor the air/fuel mixture. The latest generation of "wideband" oxygen sensors from Robert Bosch are smarter, faster, more durable and capable of precisely measuring exact air/fuel ratios - a feat that was impossible with earlier generations of O2 sensors.

Traditionally, oxygen sensors have been used to monitor the level of unburned oxygen in the exhaust.The amount of oxygen that's left in the exhaust following combustion is a good indicator of the relative richness or leanness of the fuel mixture.

When air and gasoline are mixed together and ignited, the chemical reaction requires a certain amount of air to completely burn all of the fuel. The exact amount is 14.7 lbs of air for every pound of fuel. This is called the "stoichiometric" air/fuel ratio. It's also referred to the the Greek letter "lambda."

When lambda equals one, you have a 14.7:1 stoichiometric air/fuel ratio and ideal combustion. When the air/fuel ratio is greater than 14.7:1, lambda also will be greater than one and the engine will have a lean mixture.

Lean mixtures improve fuel economy but also cause a sharp rise in oxides of nitrogen (NOX). If the mixture goes too lean, it may not ignite at all causing "lean misfire" and a huge increase in unburned hydrocarbon (HC) emissions. This can cause rough idle, hard starting and stalling, and may even damage the catalytic converter. Lean mixtures also increase the risk of spark knock (detonation) when the engine is under load.

When the air/fuel ratio is less than 14.7:1, lambda also is less than one and the engine has a rich fuel mixture. A rich fuel mixture is necessary when a cold engine is first started, and additional fuel is needed when the engine is under load. But rich mixtures cause a sharp increase in carbon monoxide (CO) emissions.

When the relative proportions of air and fuel are "just right," the mixture burns clearly and produces the fewest emissions. The trick is balancing the mixture as driving conditions, temperatures and loads are constantly changing. That's where oxygen sensors come in.

By monitoring the level of unburned oxygen in the exhaust, the sensor(s) tell the engine computer when the fuel mixture is lean (too much oxygen) or rich (too much fuel). To compensate, the computer adjusts the fuel mixture by adding more fuel when the mixture is lean, or using less fuel when it is rich.

That's the basic feedback fuel control loop in a nutshell.  The trouble is, conventional oxygen sensors give on a rich-lean indication. They can't tell the computer the exact air/fuel ratio. When the air/fuel ratio is perfectly balanced, a convention O2 sensor produces a signal of about 0.45 volts (450 millivolts). When the fuel mixture goes rich, even just a little bit, the O2 sensor's voltage output shoots up quickly to its maximum output of close to 0.9 volts. Conversely, when the fuel mixture goes lean, the sensor's output voltage drops to 0.1 volts.

Every time the oxygen sensor's output jumps or drops, the engine computer responds by decreasing or increasing the amount of fuel that is delivered. This rapid flip-flopping back and forth allows the feedback fuel control system to maintain a more-or-less balanced mixture, on average. But this tried-and-true approach that has worked so well thus far isn't accurate enough to meet the latest emissions requirements.

The new NLEV (national low emission vehicle) standards plus California's LEV (low emission vehicle), ULEV (ultra low emission vehicle) and SULEV (super ultra low emission vehicle) standards all require very precise control over the air/fuel ratio. Reducing cold emissions when the engine is first started is absolutely critical to meeting these standards. But conventional oxygen sensors (even with heaters) warm up too slowly to provide the degree of accuracy needed to meet cold emissions. They also lack the ability to tell the PCM the exact air/fuel ratio, something that is becoming increasingly necessary as advanced fuel control strategies are introduced. A simple rich

The Wideband Air/Fuel Sensor
The newest generation of oxygen sensors are being called "wideband" lambda sensors or "air/fuel ratio sensors" because that's exactly what they do. They provide a precise indication of the exact air/fuel ratio, and over a much broader range of mixtures - all the way from 0.7 lambda (11:1 air/fuel ratio) to straight air!

The Bosch LSU 4 wideband oxygen sensor is a 5-wire sensor that reads oxygen in much the same way as a traditional oxygen sensor. but it uses the latest "planar" construction with a special two-part sensing element to measure how much oxygen is in the exhaust.

In 1997, Bosch developed a new type of construction for oxygen sensors that uses a flat ceramic zirconia element rather than a thimble. It's called a "planar" sensor because the sensor element is a flat strip of ceramic that is only 1.5mm thick. The electrodes, conductive layer of ceramic, insulation and heater are laminated together on a single strip. The new design works the same as the thimble-type zirconia sensors, but the "thick-film" construction makes it smaller and lighter, and more resistant to contamination. The new heater element also requires less electrical power and brings the sensor up to operating temperature in only 10 seconds.

In creating the new LSU 4 wideband air/fuel ratio sensor, Bosch combined the oxygen-sensing "Nernst" cell from the planar sensor with an "oxygen pump" to create a device that can actually measure air/fuel ratios. Here's how it works:

The Nernst cell still senses oxygen in the same way that a conventional thimble-type O2 sensor does. When there's a difference in oxygen levels across the zirconium dioxide sensor element, current flows from one side to the other and produces a voltage. But, as we said earlier, this isn't good enough because it gives only a gross rich-lean indication of the air/fuel mixture.

To get the added precision, the oxygen pump uses a heated cathode and anode to pull some oxygen from the exhaust into a "diffusion" gap between the two components. The Nernst cell and oxygen pump are wired together in such a way that it takes a certain amount of current to maintain a balanced oxygen level in the diffusion gap. And guess what? The amount of current required to maintain this balance is directly proportional to the oxygen level in the exhaust. This gives the engine computer the precise air/fuel measurements it needs to meet the new emission requirements.

The wideband oxygen sensor receives a reference voltage from the engine computer and generates a signal current that varies according to the fuel mixture.

When the air/fuel mixture is perfectly balanced at 14.7:1 (the stoichiometric ratio and lambda equals 2), the sensor produces no output current. When the air/fuel mixture is rich, the sensor produces a "negative" current that goes from zero to about 2.0 milliamps when lambda is 0.7 and the air/fuel ratio is near 11:1.

When the air/fuel mixture is lean, the sensor produces a "positive" current that goes from zero up to 1.5 milliamps as the mixture becomes almost air.

The Bosch LSU 4 wideband oxygen sensor has a response time of less than 100 milliseconds to changes in the air/fuel mixture, and reaches operating temperature of 700 to 800 degree Centigrade (1,400 degree F) within 20 seconds or less using its internal heater. This is nearly twice the operating temperature of a conventional oxygen sensor.

Other Uses
Many performance engine builders and tuners have discovered the benefits of using the wideband oxygen sensor technology to monitor air/fuel ratios. Being able to see the actual air/fuel ratio at any given instant in time allows the fuel mixture to be fine-tuned and adjusted on the fly - something which previously could only be done on a dynamometer using expensive equipment.

The air/fuel ratio is critical with high performance, turbocharged and supercharged engines to make power and to keep the engine from leaning out at high rpm and boost pressures. If the mixture leans out, it can send the engine into self-destructing detonation.

Reference:  http://tayloredge.com/reference/Science/oxygensensor3.pdf


Bosch Wideband Oxygen Sensor Diagnostics


Because of the internal circuitry used in a wideband oxygen sensor, you can't hook up a voltmeter or oscilloscope to read the sensor's output directly. A wideband O2 sensor produces a current signal that varies not only in amplitude but direction. That makes it quite different from a conventional oxygen sensor that produces a voltage signal that bounces back and forth between 0.1 and 0.9 volts.

The only way you can currently diagnose a wideband oxygen sensor is through the vehicle's on-board diagnostic system using a scan tool.

You can use the scan tool to read the actual air/fuel ratio, and to check the sensor's response to changes that should cause a change in the air/fuel ratio. Opening the throttle wide, for example, traditionally causes a sudden and brief lean condition followed by a richer mixture as the computer compensates. But with the new control strategies made possible with wideband O2 sensors, the air/fuel ratio remains steady when the throttle is snapped open.

The diagnostic strategies for wideband O2 sensors vary from one vehicle manufacturer to another but, as a rule, you'll get an oxygen sensor code if the sensor reads out of its normal range, if the readings don't make sense to the computer (should indicate lean when lean conditions exist, etc.) or if the heater circuit fails.

One thing to keep in mind about wideband O2 sensors is that they can be fooled in the same way as a conventional oxygen sensor by air leaks between the exhaust manifold and head, and by misfires that allow unburned oxygen to pass through into the exhaust. Either will cause the sensor to indicate a false lean condition which, in turn, will cause the computer to make the engine run rich.

Other Wideband Sensors
It's important not to confuse Bosch wideband O2 sensors with those produced by other OEM suppliers. With some other wideband O2 sensors (such as those used in 1996 and newer Toyotas, for example), a scan tool will display a "simulated" voltage reading between 0 and 1 volt. The actual voltage output from the sensor is much higher, but the computer is calibrated to divide the sensor's actual output by 5 to comply with OBD II regulations that require a display reading of 0 to 1 volts (these regulations have since been revised to allow the actual voltage to be displayed.)

Sensor Replacement
Bosch wideband oxygen sensors are designed for an operational life of 100,000 miles. Replacement should be needed only if the sensor has failed due to unusual operating conditions, physical damage, or contamination. Blowing a head gasket can allow silicon to enter the exhaust and contaminate the sensor. Oil burning can allow phosphorus to enter the exhaust and contaminate the sensor. If replacement is necessary, use the same type of wideband sensor as the original.

Reference:  http://tayloredge.com/reference/Science/oxygensensor3.pdf








  Tuning 101 AFR Control Center

If you want to obtain the largest mileage gains possible...from any HHO Generator, you must modify the signals from 4 sensor groups. Just doing the O2 Sensors, with an EFIE, will not get it done on most vehicles.

This is the only product on the market that can get it done.





  Dual EFIE (Analog)

An Electronic Fuel Injection Enhancer is used to adjust the signal from the oxygen sensor before they get to the engine's computer to compensate for an increase in fuel efficiency brought about by another fuel efficiency device. The Dual version handles two oxygen sensor.

  Digital EFIE

The Quad Digital EFIE Basic is the newest member of our family of EFIE's. Digital EFIE's allow much leaner settings on vehicles than other types of EFIE. We recommend Digital EFIE's for all narrow band oxygen sensors that are upstream of the catalytic converter. Note, that the Quad EFIE uses a pair of analog EFIE's for the downstream sensors.

  Frequency MAP / MAF Enhancer

Our new frequency based MAP/MAF enhancer is the first universal MAP/MAF Sensor Enhancer.  It can be used for devices that output a frequency to the computer, or devices that send an analog voltage signal.


Eagle-research EFIE - sold from their web site

  EFIE Kit, unassembled - eagle-research.com

  EFIE, Assembled - eagle-research.com

  Adjusting the EFIE (video)

Regardless of what you read elsewhere, this EFIE works on ALL types of oxygen sensors, including Titania (varying resistance) sensors, A/F sensors and wideband sensors.

EFIE Documentation /Instructions/Tuning/etc.
EFIE Circuit Schematic and Parts List
Dealing with the Vehicle Computer (EFIE & MAP/MAF)
  Page Last Edited - 04/03/2022

    Copyright 2003   All rights reserved.   Revised: 04/03/22.                                             Web Author, David Biggs
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