Haltech E6K - Manual (Page 92)

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ONLINE and go to the Output Options Page. Ignition will need to be switched on. Select
Closed Loop Control, and adjust the following parameters as necessary.
Note: The closed loop control will not work for the first 2 minutes after the
ECU is switched on; this allows sufficient time for the oxygen sensor to reach
operating temperature.
Lower RPM Limit
The engine must be running above this speed for the closed loop function to operate.
Normally this would be set a few hundred rpm above or below idle, depending on
whether you wish closed loop control to occur at idle speeds.
Upper Throttle Limit
It is generally undesirable to run an engine at stoichiometric air-fuel ratio when under
load. This parameter is used to determine when the driver is demanding sufficient
engine output to disengage the closed loop function. The smaller this number, the
earlier the feedback control will drop out.
Engine Cycles Between Corrections
The oxygen sensor does not respond immediately to the exhaust gases of the
combustion which has just taken place. There is a gas transportation time from the
engine to the sensor, plus the sensor reaction time itself. Consequently, the ECU
counts a number of engine cycles before accepting the reading from the oxygen
sensor. If the closed loop function is responding erratically, constantly overdriving to
the adjustment limits, or if there is insufficient oscillation in the air-fuel ratio for the
catalytic converter to operate, increasing this parameter may help. If it is set too high,
the feedback loop will be noticeably slow to respond to change.
O2 Sensor Threshold Voltage
This is the sensor voltage by which the E6K determines whether the engine is lean or
rich; it is the target that is sought to be maintained. This is normally set to the voltage
that corresponds to an air-fuel ratio of 14.7:1, the NGK heated 4-wire sensor threshold
voltage is around 600mV this value will vary for different sensors. It is also known as
the sensors reference voltage.
Maximum Fuel Increase
The closed loop algorithm will be permitted to increase the fuel injection time no
further than this limit while attempting to enrich the mixture. The valid range for this
limit is 5% to 12.5%.
Maximum Fuel Decrease
Again a range of 5% to 12.5% applies to this parameter which is the limit of correction
permitted to the base fuel injection time when leaning the mix.
Note: It is preferable to keep the increase and decrease limits small (say around
5-10%). Excessive swinging of the air-fuel ratio can result in surging and poor
operation of the catalytic converter. The closed loop algorithm should never be
used as means to correct bad mapping.