The ECU has the feature to control different types of idle motors found on an engine. Before adjusting the idle control settings, you need to select which type of valve or stepper is on the engine. Note: The stepper types idle motor (4 to 6 wire), require the external electronic driver. Also note that the electronic unit differs between the 4 Wire bipolar type motor and the 6 Wire common supply type motor.

Type Selection

The Type Selection can select between the two-wire spring-loaded Idle Valve, the three-wire spring or non-spring loaded Dual idle valve, the Bipolar Stepper motor or common supply Stepper motor. Stepper motors do not use the Low Limit and High Limit settings as they keep their position when there is no signal present. If there is no idle control select ‘Not’ used to free up valuable processor time and general purpose outputs.

Idle Valve

Two wire spring loaded idle valve only use one output from the ECU.

Dual Idle Valve

Three spring or non-spring loaded idle valve two outputs from the ECU.

Stepper Motor

Four or Six wire idle valves operate with a Spitronics Type 1 or Type 2 stepper motor controller, use one output from the ECU.

Settings

Drivers

This indication will show the installer which wires to connect on which outputs of the ECU. Driver 2 is only used for the dual valve to close. Note that positive and negative drivers may be used for idle control. If a valve is used, then make sure the Diode across it is wired correctly. (See the wiring diagrams and general purpose priority spreadsheet for correct installation.)

RPM

This setting is the target RPM’s when the engine is on running temperature. When it is cold the ECU will automatically increase engine RPM’s with up to 300 RPM’s. This is calculated according to fuel enrichment on the water compensation map. Every 15% will increase 100 RPM on the Idle control.

Start %

This setting is used to increase the air intake when the engine is started hot or cold. The ECU will open the idle valve with this %. Note that on stepper controls it will activate 25% every time the key is switched on. If you don’t start it, it may idle high at first then come back to idle target.

Response Time Up

This setting will determine the rate at which the valve opens when the actual RPM’s fall below the set point in Idle RPM. The further the RPM fall below the set point, the faster the ECU will open the valve to let in more air. Low values will create a faster response time and high values will create a slower response time. This setting must prevent the engine from stalling when you switch the air conditioner on, or put it in drive.

Response Time Down

This setting will determine the rate at which the valve closes when the actual RPM’s go above the set point in Idle RPM. The further the RPM goes above the set point, the faster the ECU will close the valve to decrease airflow into the engine. This value is set higher than the Response Up value, to eliminate hunting. Low values will create a faster response time and high values will create a slower response time. This setting must bring fast idling down as fast as possible without hunting the engine.

Low Limit duty cycle

This setting will preload the solenoid against the spring in the idle valve so that the valve starts to open immediately when the ECU starts increasing the value. It can also be used to set minimum idling RPM for throttle valves that closes completely. To set the value start with a larger % and decrease until the desired idling RPM is reached.

High Limit duty cycle

This setting is used to limit the maximum idle RPM’s. No need to open the valve more than necessary. It also allows for the use of large valves in smaller engines. Make sure that when the engine is cold, it can still lift the RPM up to approx. 1500 RPM. This can be tested by entering a large Idle RPM value and limit the ECU from increasing it too high.

TPS Idle Cutoff %

This value is used to disable the idle control when the driver touches the throttle. The reason is that the ECU must know when not to control idle as the driver may need just a minimal amount of revs with slight throttle.