ECM F/A1000, Instruction Manual

Page: 7 / 26

3
How to Use
Hooking-up the F/A Monitor
Location of the UEGO Sensor
The UEGO sensor should be located from 12" to 48” from the exhaust valve(s) of the engine.
A location further from the engine may be used as long as it is at least ten times the exhaust
pipe diameter upstream of the end of the exhaust system. For example, with a 2½" diameter
exhaust pipe, the sensor should be at least 25" upstream of the end of the exhaust. The
problem with locations further downstream than ten diameters is that reversion air may be
trapped in the exhaust giving leaner than actual readings. This especially occurs at low
exhaust flowrates (i.e. idle). Locating the UEGO sensor far from the engine exposes the
sensor to more liquid water during both start-up and normal operation and is not
recommended.
When choosing a UEGO sensor location, take into consideration engine movement, ground
clearance, and wire harness routing.
Mount the UEGO sensor in a location where the sensor’s wires are pointing upward (9
o’clock to 3 o’clock). Do not mount the sensor where liquid inside the exhaust may
collect in the sensor or its threads.
Install the UEGO sensor by lightly coating its threads with a non-lead containing antiseize
compound and tighten it to 30
± 3 ft-lbf (40 ± 4 Nm). Attach the sensor to the wiring harness
and route the harness to the control module. Use cable ties to keep the harness away from hot
or moving objects and ignition wires.
Do not modify the wiring harness. Replace the wiring harness if it becomes damaged.
Installation of the Sensor Mounting Boss
The UEGO sensor is mounted in the engine's exhaust by threading it into a M18X1.5mm
boss that is cast, welded, or brazed onto the engine's exhaust pipe. This thread size is
identical to that of most exhaust oxygen sensor (O
2
sensors) used in production automobiles
with 3-way exhaust catalysts.
The sensor boss provided has a M18X1.5mm thread. To mount the boss, first drill a ¾"
diameter hole in the desired location. Clean the area around the hole with a wire-brush and
clamp the boss over the hole. Weld or braze the boss to the exhaust pipe. After the boss is
attached to the exhaust, tap the treads to clean them and file the top of the boss to provide a
flat surface for sealing.
When the UEGO sensor is not being used, use the supplied plug (with some anti-seize) to
plug the hole. Do not use the UEGO sensor to plug the hole when the control module is not
powered-up.