Four basic idle actuator types are supported by Link ECU's, these are 2 wire Solenoids, 4&6 terminal Stepper Motors, Ethrottle and 3 wire Solenoids. Each actuator type has it's own requirements and settings as outlined below.
Solenoid Idle Speed Actuators work by using a PWM Signal with a varying Duty cycle which controls how open the solenoid is. Idle Solenoids come in two common types, 2 wire and 3 wire with 2 wire solenoids requiring a power feed and one auxiliary output and 3 wire requiring a power feed and two auxiliary outputs, this mode supports the type that only uses one auxiliary output. Some idle solenoid actuators aren't designed to be driven to the ends of their travel and the Min and Max Clamps when set properly can help prevent issues arising from this. The ISC Override settings in Antilag can set the actuator position outside of the min/max clamp range so be aware of this when setting it up.
·Output - The Auxiliary output to be used for opening the idle speed solenoid.
·PWM Frequency - The frequency at which the idle solenoid will be controlled, a typical value would be 200Hz
·Voltage Compensation - When turned on the Duty Cycle of the Auxiliary is adjusted based on how far the battery voltage is from 14V (while still being clamped between the min and max). This means that the actual position of the solenoid should be more consistent with the desired position over variations in the vehicle voltage.
Stepper
A Stepper Idle Actuator requires 4 Auxiliary outputs to control a stepper motor that opens and closes the idle speed valve. On Link ECU's the 4 Auxiliary outputs used must be Aux5-8. Stepper motors usually come in two different types, Unipolar usually identified by having 6 wires and Bipolar which is usually identified by having only 4 wires. Unipolar stepper motors require a power feed and the Auxiliary outputs controlling it only need to pull to ground. Bipolar stepper motors don't require a power feed as the Auxiliary outputs controlling it pull both to ground and to 12V.
Idle stepper motors need to reset either on ecu start up or ecu power off so that they are in a known position when the ecu starts controlling them, this can require ECU Hold Power to be set up if the stepper is being reset on power off.
Unipolar (6 wire) stepper motors can force the ecu to stay powered on after the normal ecu power supply is turned off if wired wrong, the power supply to the stepper motor can backfeed through the auxiliary outputs and power the ecu. This means that when wiring up a stepper motor care needs to be taken to ensure that the stepper power must be taken from the same power source as the ECU (e.g. the ECU Hold Power Relay).
The ISC Override settings in Antilag can set the actuator position outside of the min/max clamp range so be aware of this when setting it up.
·Stepper Motor Type - This setting allows the user to select the type of stepper motor being used, the reverse types simply treat the opposite direction as open and so are to be used if you find the stepper is being driven in the wrong direction. Swapping Aux 5&6 around or swapping Aux 7&8 around will also change the direction of the motor, do not swap both.
·Stepper Motor Steps - The number of steps the stepper motor has over it's range of operation, this value determines what 50% or any other percentage of open means.
·Stepper Reset - This setting determines when the stepper motor resets it's position, at Key-On, Key-Off (requires ECU Hold Power to be set up) and Key-On Fuel Lockout which prevents fuel from being injected and ignition from occurring until the stepper motor is in position to start (the one exception to this is that pre crank fuel will still be injected but without ignition this will not fire the motor). Some cars have enough flow through their stepper idle control to hold the engine at a significant engine speed and Key-On Fuel Lockout can be used to prevent a surge in engine speed when the car starts before the stepper motor is in the correct position.
·Stepper Hold Duty Cycle - This setting controls the Duty Cycle used to hold the stepper motor in position when it is not moving. A lower Duty Cycle when stationary can help prevent overheating of the stepper motor, a typical value would be 20-30%.
Ethrottle
One of the many bonuses of using an Ethrottle is that it doesn't require a separate idle speed actuator, the throttle plate is simply held slightly open when idle conditions are met.
When using an Ethrottle as the idle actuator the position of the throttle is controlled by a combination of the idle position and Ethrottle position in such a way that the throttle responds immediately to pedal input while in idle and there is a smooth transition between the idle target and accelerator pedal target as the pedal position is increased up until a short distance past the idle target position where the throttle position becomes solely dependant on the EThrottle target table. This is done to ensure a smooth and responsive entry and exit from idle speed control without incurring undershoot of throttle position.
The use of an Ethrottle idle actuator also means that you have the ability to flow a lot more air through your idle actuator than other forms and so the Min&Max Clamp, Base Position Table and various offset values need to be much lower than they would for a solenoid or stepper actuator. We typically recommend a Max Clamp of 10% or less to ensure that the engine isn't inadvertently revved too high under idle conditions.
Note that the ISC Override settings in Antilag can set the actuator position outside of the min/max clamp range so be aware of this when setting it up.
Note that when using Ethrottle for idle control a very small change in throttle position will result in a large variation in engine speed.
Solenoid Idle Speed Actuators work by using a PWM Signal with a varying Duty cycle which controls how open the solenoid is. Idle Solenoids come in two common types, 2 wire and 3 wire with 2 wire solenoids requiring a power feed and one auxiliary output and 3 wire requiring a power feed and two auxiliary outputs, this mode supports the type that only uses two auxiliary outputs. Some idle solenoid actuators aren't designed to be driven to the ends of their travel and the Min and Max Clamps when set properly can help prevent issues arising from this. The ISC Override settings in Antilag can set the actuator position outside of the min/max clamp range so be aware of this when setting it up.
·Output - The pair of Auxiliary outputs to be used for opening the idle speed solenoid.
·PWM Frequency - The frequency at which the idle solenoid will be controlled, a typical value would be 200Hz