Accelerator throttle case (throttle case)

ACCELERATOR THROTTLE CASE (THROTTLE CASE)

The amount of air taken in is determined by the opening of a throttle at the beginning of the intake manifold. The throttle is controlled by the accelerator pedal. Air necessary to keep the engine idling (with throttle closed) and appliances activated is regulated and by-passed solely by the engine idle speed actuator.

The arrowed screw is used to adjust throttle closure correctly in order to prevent fouling against the surrounding circuit; this screw should not be used to adjust idle because it is set by flushing during manufacture and must never be tampered with.

ENGINE IDLE SPEED ACTUATOR

This consists of an electric motor, with armature (1) visible, a supply terminal block (2) and rotary distributor (3). By opening supplementary air passage - in parallel with leakage flow from throttle (with accelerator released) - in the throttle case by varying amounts, this keeps engine idle speed constant automatically whatever the engine load (supplementary appliances on or off, engine warm or cold etc.).

The passage opening brought about by distributor rotation is governed by electrical pulses processed by a special section of the injection ECU, which turns the distributor one way or another according to engine speed.

The actuator must be positioned correctly upon installation. Air flow through the valve is shown by an arrow.

1. Armature winding
2. Connector
3. Rotary distributor