OMEM710 Hardware Manual 2v11
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The ECU can take inputs from either narrowband or wideband oxygen sensors. This information is
then used to make constant trims to the fuelling.
For banked engine with two exhausts, the ECU can take inputs of two lambda sensors. To assign
the fuel outputs to the oxygen sensors, use the Ox FB Sensor Select option group.
There is a large amount of theory, and many different options, involved in setting up the complicated
oxygen feedback as this ECU is capable of meeting very strict emissions requirements. Fortunately,
these complicated equations have already been tackled, and nearly all engines require the same
settings for oxygen feedback, so it can be set relatively easily.
15.1 Narrowband
Basic
A narrowband exhaust gas oxygen sensor may be used to trim the fuelling to maintain a
stoichiometric (lambda=1) air/fuel mixture to enable the use of an exhaust catalyst. Any 3 or 4 wire
(ie heated) narrow band lambda sensor can be used.
Start-up calibrations from Omex will be programmed with oxygen feedback numbers for narrowband
sensor feedback so in most cases all that is required is to turn on the function.
OX FB Below Load and OX FB Below RPM are the engine load and engine RPM values below
which the oxygen feedback is active. Typically these cover the emissions test and gentle driving
conditions. eg 4000rpm and 40% load
OX FB Coolant min is the minimum engine coolant temperature at which the engine is able to
run at lambda 1 ie the temperature at which it no longer requires warm-up fuel enrichment.
Typically 60-70C.
OX FB Rate is the update rate of the sensor, typically 100. Setting this to 0 disables the oxygen
feedback.
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