Deceleration Control System: Operation
When engine is at normal operating temperature and throttle is suddenly closed, deceleration fuel cut-off begins when the engine speed reaches 1800 RPM. Deceleration is detected by a microswitch and deceleration relay.
When engine is above 1800 RPM, deceleration relay allows positive current to the deceleration valve. This causes throttle flap to move against idle stop which closes microswitch. This energizes 2-speed relay which grounds cold cut-out relay and opens thermocontact.
The deceleration valve opens and equalizes pressure on airflow sensor. Injection is resumed when engine reaches 1200 RPM or is accelerated.