Series II
ODYR-13-2 & SLX-13-2
AIR FUEL RATIO MONITOR
Introduction:
The Odyssey Series II gauges from Dakota Digital, Inc. incorporates the reliability and quality of
our standard gauges, along with several unique features and easy mounting. These features include:
•
Industry standard 2-1/16” gauge size.
•
A warning feature that flashes the gauge readout when outside operating limits.
•
User adjustable warning points.
•
Microprocessor stabilized readings.
•
Adjustable averaging to set how the gauge responds.
•
Night dimming with lens label lighting.
•
Non-Glare, high contrast lens.
•
High Visibility VFD display for sunlight readability.
WIRING COLOR CODE FOR GAUGE:
RED
+12 volt power with key on
BLACK
ground for gauge and case
(the ring terminal should attach to the top screw on the case.)
GRAY
oxygen sensor ground
WHITE/RED setup
input
GREEN
oxygen sensor signal
BLUE
night
dimming
Operation:
The air/fuel mixture gauge will display the exhaust gas oxygen sensor output in mV. The range
of the readout is from 000 – 999 with 999 indicating an input greater than 1.0 volts. An output voltage of
450mV – 500mV from the sensor is considered the
λ
=1 area. This is the ideal air/fuel mixture for reduced
exhaust emissions and general engine operation. Best fuel economy will be slightly leaner than this and
best power will be found with a richer mixture. A fuel injection computer monitors the oxygen sensor to
maintain an average fuel mixture in this ideal range.
An output voltage that is higher (800 mV – 995mV) indicates a rich fuel mixture (
λ
<1). An output
voltage that is lower (50mV – 200mV) indicates a lean fuel mixture (
λ
>1). A standard EGO sensor will
only indicate 3 states; lean, rich, or
λ
=1. The transition area of the sensor is very sharp and does not
convert into an exact air/fuel ratio except at
λ
=1; which is 14.7:1 for gasoline, 6.5:1 for alcohol, and 15.6:1
for propane.
The use of leaded fuel will seriously shorten sensor life.
If leaded fuel is being used,
the sensor should only be installed during tuning and then removed and a plug placed into the hole.
On a carbureted engine, the engine will not automatically adjust the air/fuel mixture. This must
be adjusted manually and can be optimized for economy or performance. The air/fuel mixture gauge will
provide the information required for proper fuel mixture adjustment.
POWER
Connect the red wire from the main harness to accessory power from the ignition switch.
Never connect this to a battery charger alone. It needs to have a 12 volt battery connected to it.
Battery chargers have an unregulated voltage output that will cause the system to not operate properly.
GROUND
The black wire is the main ground for the gauge. A poor ground connection can cause improper
or erratic operation. The black wire loops over to the top screw on the back of the case. This ensures a
good case ground connection.
