OMEX OMEM710 - Page 38

OMEM710 Hardware Manual 2v11
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If there is NOT an adjustable air bleed screw or adjustable throttle stop;
6. Set the whole of the Idle Duty Fuel Trim Table to 30% and set all hot temperatures in the Idle
Duty Coolant table to a value which allows the engine to idle at the target idle speed. Ensure
that the engine is running at the correct AFR as the wrong AFR will make the engine run slowly.
Change the fuelling in the main Fuel Map as required to maintain the correct AFR at the idle
speed.
7. Ensure that the main Fuel Map is calibrated correctly down to stall speeds and at both closed
throttle and the first site above closed throttle. This is best achieved through loading the engine
on the dyno. Typically, as the engine goes towards stall speeds, there is a large increase in
fuelling requirements.
8. In the Idle Duty Coolant Table, set various openings of the idle motor from 0-100%, load the
engine on the dyno to hold (approximately) the target idle speed, then adjust the Idle Duty Fuel
Trim Table to maintain the correct AFR.
9. Return all warm temperature values in the Idle Duty Coolant Table to a value that maintains
the target idle speed.
Setting Hi Idle
When the engine enters Hi idle conditions, the option Hi Idle Duty is the increase in duty cycle
required to reach the Hi Idle Target RPM+. The Hi Idle Target RPM+ would typically be 200 or
300rpm.
 With the engine warm, fix the Hi Idle condition permanently on by setting the temperature entry
condition, Hi Idle below Cool, to 120degrees.
 Watch parameter Idle Set to see the increase in idle duty required to hold the higher engine
speed.
 Enter the Idle Set value into Idle Hi Duty.
 Reset Idle Hi Below Cool to a suitable cold running value eg below 60degrees.
Setting Aircon Idle
When an air conditioning pump switches ON, the load on the engine increases and so the idle
speed will momentarily decrease. The idle feedback loop will allow the idle speed to recover, but the
Idle A/C Duty+ option is an instant increase in idle motor duty when the A/C input is ON so that the
momentary dip in engine speed is reduced.