Removal/refitting

The two actuator windings, for idle speed, are supplied with two complementary duty-cycle signals i.e. they receive voltage and produce opposite forces on the rotor.

A determine number of pulses, with the battery voltage and winding temperature constant, correspond to a well-defined angular position of the rotary valve and, therefore, a precise opening section of the by-pass. The idle speed regulator is controlled by a part of programme stored in the control unit. The constant idle speed actuator is mainly used to determine the exact amount of air when starting and for maintaining an ideal idle speed condition under all engine conditions.

REMOVAL/REFITTING

• Disconnect the battery (-) terminal.

1. Disconnect the electrical connection from the constant idle speed actuator.
2. Disconnect the air intake pipe from the constant idle speed actuator.
3. Slacken the clamp fastening screw and remove the constant idle speed actuator.

CHECKS AND INSPECTIONS

For checking the operation of the electromagnetic part of the actuator see GROUP 55 - "ELECTRIC SYSTEM DIAGNOSIS".

THROTTLE POTENTIOMETER

This is a potentiometer, the mobile part of which is controlled directly by the throttle valve shaft. The potentiometer informs the control unit instantly when there is the need for "full power", anticipating the signal from the air flow meter which records a considerable increase of the air flow thereby obtaining an immediate response. The potentiometer automatically detects the throttle contact position by a "self-adapting" function. This dispenses with the need to adjust the potentiometer and makes it possible to follow any wear occurring on the throttle closed position over the course of time.

REMOVAL/REFITTING

• Disconnect the battery (-) terminal.
• Remove the resounder (see specific paragraph).

1. Slacken the clamp fastening to the air cleaner box, slacken the front fastening bolt and remove the air intake duct.