How To Use; Hooking-Up The Afm - ECM AFM1040 Instruction Manual

How to Use

Hooking-up the AFM

Location of the Lambda Sensor
The lambda 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 less than ten diameters upstream is that reversion air may be
trapped in the exhaust giving leaner than actual readings. This especially occurs at low ex-
haust flowrates (i.e. idle). Locating the lambda 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 lambda sensor location, take into consideration engine movement, ground
clearance, and wire harness routing.
Mount the lambda 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 lambda 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 lambda 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 sensors (O sensors) used in production automobiles
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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 lambda sensor is not being used, use the supplied plug (with some anti-seize) to
plug the hole. Do not use the lambda sensor to plug the hole during engine operation when
the control module is not powered-up.
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