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Installing and connecting the air/fuel ratio gauge – Mallory Ignition ACCEL Engine Analyzer Series Wideband Oxygen Sensor 77062_77062n_77062s_77063 User Manual

Page 9

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8


Installing and Connecting the Air/Fuel Ratio Gauge


Locate the three wires on the back side of the air/fuel ratio gauge. The following

table outlines each of the connections necessary to operate the DFI air/fuel ratio
gauge with the Engine Analyzer series wideband controller.

Wire color

Function

Connect to

Red

Gauge power

Switched +12V source

Black

Gauge ground

Main ground source for wideband controller

Gray

Signal input

Gauge output wire on wideband controller

¾ The gauge can be mounted in a 2 1/16” hole or gauge pod. Mounting

hardware is included for panel-mount installations.

¾ It is important to connect the black gauge ground wire to the same grounding

point as the main ground wire for the controller. This is necessary to prevent
ground loops that could cause the gauge reading to be incorrect. The main

ground for the controller is on pin C of the 4-pin connector labeled “0-5V
output” in the wideband controller harness.

¾ Connect the gray wire on the gauge to the gray wire coming from pin 9 on

the wideband controller.

¾ The red power wire should be connected to a switched +12V source.


The Accel DFI air/fuel ratio gauge is designed specifically to operate with this
controller. The multi-color LED sweep display around the perimeter of the gauge

face is specially calibrated to provide instant feedback to the driver by changing
colors as the air/fuel ratio range varies. Even if the driver’s attention can’t be

focused on the numbers in the gauge, the color of the LED on the sweep display will
immediately alert the driver if the air/fuel ratio is out of the intended range.


The gauge output from the wideband controller produces a voltage that is equal to
the air/fuel ratio being measured. For example, a 12.8 volt signal means that the

air/fuel ratio is 12.8:1.

If you choose to use a different gauge, you may only use a self-powered digital
voltmeter. Analog voltmeters or gauges will not operate correctly with this

controller.