Dynalco AF-900PC Air/Fuel Ratio Controller - Manual (Page 9)

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6.2 Mounting the Heated Oxygen Sensor(s)
The heated oxygen sensor(s) should be mounted in the exhaust pipe as close to
the engine exhaust manifold as possible. A single bank engine requires only one
sensor. For dual bank “V” engines, the left and right bank sensors should be
mounted as close to the engine exhaust manifold as possible to eliminate cross
talk between the two banks.
CAUTION: The sensor(s) must be mounted where the temperature on the
outer shell does not exceed 400
O
F (204
O
C).
Above 400
o
F, sensor life will deteriorate rapidly and output voltage will be affected.
The sensor(s) should be mounted on a horizontal plane or above horizontal to keep
water from accumulating on the sensor tip. The sensor(s) should also be mounted
where they are accessible as sensor replacement is recommended every 2000
hours. It is recommended a fitting with 18mm x 1 ½ internal threads be welded into
the exhaust pipe for each sensor to be mounted. This will provide a flat mounting
surface for the sensor to avoid exhaust leaks. Sensors should be mounted with an
anti-seize compound on the threads.
NOTE: Recommended torque for mounting the sensors is 28 – 38 ft-lbs.
The conduit for the oxygen sensor should be routed to avoid close proximity to high
tensions ignition cables and coils to minimize potential EMI interference. Ignition,
flow control valve, and power wiring must not be placed in the same conduit with
oxygen sensor wiring. The conduit should also be routed where temperature does
not exceed 200
o
F.
6.3 Mounting the K type thermocouples (ungrounded must be used)
Optional thermocouples may be installed in the exhaust pipe to monitor pre and
post catalyst temperatures. The AF900PC will also calculate the differential (or
delta) temperature to help ensure proper catalyst operation. An NPT tap should be
used to tap the hole for the thermocouple. An adjustable fitting on most
thermocouple probes will allow proper insertion depth into the exhaust stream. The
thermocouples should be connected to the AF900PC terminal block using
thermocouple extension wire to eliminate erroneous readings.
6.4 Installation of M-201 Magnetic Pickup for Speed Sensing
The M201 magnetic pickup detects engine speed by sensing flywheel gear teeth as
they pass by. The pickup must be mounted on a bracket or flywheel cover so that it
is perpendicular to the face of the flywheel teeth it is sensing. The M201 requires a
5/8-18 UNF thread for mounting. The gap between the pickup pole piece and the
gear teeth should be set to 0.020” to 0.030”. Once the gap has been set, the pickup
should be secured with the lock nut. The M201 should be connected to the
AF900PC with a C101 pickup cable/connector.