all modern vehicles, either fuel injected or carbureted,
employ oxygen sensors to tell the vehicle's computer
if the air/fuel mixture is too rich or too lean.
The computer uses the information from the 02 sensor
to determine if more or less fuel should be added
to the mix in order to maintain the correct proportion.
vehicles are designed to operate at an air/fuel
ratio of 14.7 to 1. When these proportions are being
supplied to the engine, a certain amount of oxygen
will be detected in the exhaust by the 02 sensor,
and this information is fed into the vehicle's computer.
If more oxygen is sensed, the computer thinks the
mixture is too lean (not enough fuel), and adds
fuel to the mix. Likewise, if less oxygen is sensed,
the computer thinks the mixture is too rich (too
much fuel) and cuts back on the fuel fed to the
is actually an artificial relationship, but has
been found to be workable with the existing techniques
of burning fuel in your car's engine.
a big problem with this scenario because as soon
as you start adding a workable fuel efficiency device
like a hydrogen booster, the oxygen content in the
exhaust will rise.
you have two or more efficiency devices installed,
even more oxygen will be present in the exhaust.
The oxygen content rises as the fuel is burned more
efficiently for a number of reasons. Chief amongst
less fuel is being used to produce an equivalent
amount of horsepower, and
(2) less oxygen is being consumed to create carbon
monoxide in the exhaust.
bottom line is there is more oxygen in the exhaust
as the fuel burning efficiency is increased.
now that we have spent time and money to install
a fuel efficiency device or two, and we are getting
a more efficient fuel burn, what does the vehicle's
computer do? It dumps gas into the mix in an attempt
to get an oxygen reading in the exhaust equal to
it's earlier, inefficient setup. This will then
negate the fuel savings of just about any efficiency
device, and in some cases will actually cause an
increase in fuel consumption, despite having a workable
fuel efficiency device.
Solution is simple.
The signal coming from the 02 sensor needs to be
adjusted to compensate for the increased fuel efficiency
we need to fool the computer into thinking that
the engine is still burning gas inefficiently, by
making it think there is less oxygen in the exhaust
than there actually is.
amount of change to the signal is easily adjustable
to accommodate different amounts of efficiency increase
from different size hydrogen boosters.
should be noted that an oxygen sensor handling device
(EFIE) by itself, is not a fuel efficiency device.
The EFIE could be used to control the vehicle's
computer and make the engine burn a little leaner
and this would give a small increase in gas mileage.
But this is not what it was designed to do.
It was designed to complement, and in some cases
make possible, an increase in gas mileage using
other fuel efficiency devices such as a hydrogen
How to Adjust Your EFIE
Locate both oxygen sensor signal wires
easy way to do this is to look it up in your Haynes,
Clymer or Chilton manual for your car. OR, if you
don't have one of these, there is a service at www.ahdol.com
where you can pay a nominal fee, and get your wiring
diagrams emailed to you.
have also recently found a Free resource at www.autozone.com
whereby you can get your wiring diagram on your
Locate your car, year, make and model.
* Select "Repair Info" at the left side
of the screen.
* Then select, "Vehicle Repair Guides"
* then > Chassis Electrical > Wiring Diagrams
information is not available for all cars and trucks.
Unfortunately, the sensor can have 2, 3 or 4 wires,
and you have to know which one is the signal wire.
If you have 4 wires they will be:
1. Heater 12 Volts +
2. Heater ground
3. Oxygen sensor signal +
4. Oxygen sensor signal ground
you have 2 or 3 wires, then you can have a common
ground, or no heater wires etc.
simplest setup is a one wire O2 sensor, which is
the signal wire. The O2 sensor gets it's ground
from the exhaust pipe. But you would still use the
following procedure to narrow down which wire is
Disconnect the wire harness to the O2 sensor.
Turn on the ignition.
Probe for 2 wires that produce 12 volts between
This will be the heater circuit and ground.
The two wires left will be the sensor signal and
the wiring harness, then strip a little insulation
off each of these wires and measure them with the
You should get voltage reading that is constantly
fluctuating between 0 and 1 volt (.45-.65 volts
is common) If the readings are negative, reverse
Now the positive probe will be the signal wire you've
been looking for. Cut this wire at a convenient
location for connecting the EFIE.
call the sensor side of this cut wire the sensor
wire, and the other side of the cut, the computer
rarely an oxygen sensor wiring harness will have
more than 4 wires. In this case, the sensor is possibly
a "wide band" oxygen
EFIE is not designed to work with wide band sensors,
although some wide band sensors have an interpreter
that gives out a narrow band signal before routing
to the computer.If you have a wide band sensor please
buy the wide band EFIE
you have determined which is the sensor's signal
wire, you want to get it located up close to the
computer. If you used a manual, or wiring diagram,
you probably have already located the wire at the
computer's wiring harness. If you had to figure
out the wires at the sensor itself, then try to
find the same wire at the computer's wiring harness.
It should be the same colors, but test it with an
ohm meter to be sure.
they use the same colors for different things. Even
if it's a pain in the butt, it's worth it to get
the signal wire located up by the computer. This
makes cutting into it and hooking up the EFIE much
easier, especially if you are mounting the EFIE
inside the cab.
(2) Locate 12 volt power and ground
need to ensure that you have switched power, not
power directly from the battery.
When power is shut off to the EFIE, or the power
switch is turned off, the
original connection between the oxygen sensor and
the computer is re-established. This will
allow the EFIE to be turned off and on with your
hydrogen booster if so desired.
connecting to your hydrogen booster is inconvenient,
just use any circuit that is accessory key switched.
electrical diagram can come in handy here, and if
you don't find another device to attach to, you
can usually find a spare circuit in the fuse box
(you may have to add a fuse).
One installer used the oxygen sensor's heater power
for his EFIE's power, and this is perfectly acceptable.
can be the vehicle body, engine block or ground
from another device, including the ground for the
oxygen sensor itself.
(3) Mount the EFIE
can use the mounting ears to screw down the EFIE
to a suitable location on the vehicle body or firewall.
Some people like to mount the device inside the
passenger compartment of the car.
1. The EFIE is not 100% waterproof. If you mount
it under the hood, you will have to take care to
cover it if you need to steam clean your engine.
You may want to mount the EFIE in the passenger
compartment where it will be protected.
2. If you live in a cold climate, where temperatures
are expected to be below freezing for a significant
number of days per year, you will want to ensure
that the EFIE is mounted where it will be warmed,
either by the engine, or inside the passenger compartment.
most cases this can be accomplished by mounting
your EFIE in the upper rear of the engine compartment,
close to the firewall, which will allow it to benefit
from trapped engine heat.
Attach the wires
Connect the red to your switched power source.
Connect the black to ground.
Connect the green wire to the oxygen sensor.
Connect the white wire to the computer.
Connect the brown wire to the oxygen sensor.
Connect the blue wire to the computer.
Hopefully, you've been able to locate all these
wires up by the computer in an easily accessible
location. Be sure not to cut them too close to the
computer so that you have plenty of slack to work
should solder them and use heat shrink tubing to
insulate the connections from other wires. If you
don't have heat shrink, you can use electrical tape.
Take care to not reverse the connections for the
red and black wires as the EFIE will burn out!!!
It will make smoke and will smell bad...(;;) If
this happens, the unit can be fully restored by
merely replacing the voltage regulator. Contact
us for a new regulator if this occurs.
How to Adjust Your EFIE
Read and adjust Your EFIE .......
the leads from your VOM to the red
and black probes on
the front of your EFIE. This will show just the
voltage offset being produced by the EFIE.
on the power to the EFIE
the voltage adjust potentiometer
voltage should be set to about .1
- .3 volts.....
Most of the EFIE's that we
have tested are preset to .2 - .3 volts.
Start with .2 - .3 volts if you have a booster
.1 - .2 volts if you don't have a booster.
A higher voltage = leaner.
is all that needs to be done most of the time.
You can very this for different vehicle and different
size hydrogen boosters or other fuel saving devices.
If you set the EFIE to high you might get a check
test the output of your EFIE and o2 sensor.....
sensors have a warm up period before they operate
properly so warm up your vehicle before making adjustments.
Connect the VOM + to the red
probe and the VOM - to the
While the vehicle
is running use
the voltage adjust potentiometer to set the output
of your Deluxe EFIE to vary between .2 to .7 volts.
A higher voltage = leaner.
this when the vehicle is warm and
your booster is turned on.
the VOM connected and rev the engine up and down
to make sure the range stays between 0-1 volt.
If you take a measurement from your O2 sensor before
you connect your Booster or EFIE you can use these
numbers as a Guideline as to what voltage
to set the voltage output from your EFIE.
that is how you set the voltage.
Let's say you set the EFIE to .25 volts. Let's also
say that when reading the oxygen sensor in the previous
paragraph, you saw a fluctuating voltage between
.2 and .7 volts. When reading the computer's input
voltage you would then see a constantly changing
voltage in the range of .45 and .95. This is due
to the .2 to .7 volts the sensor is producing, plus
.25 volts that the EFIE is adding.
Dan HBN ..............................