Honda Accord
Honda Accord LX
Inducing Labor

When you start your 1987 Honda accord the rpms instantly rise what causes that?

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Wiki User
2006-08-13 17:38:16

That is the Fast Idle action required for smooth running while

the engine is warming up. On the carbureted (DX) model, a fast idle

cam props open the throttle when the engine is cold, raising the

idle. The cam is controlled by the thermostatic spring which also

controls choke position, the spring is heated by an electric

heating element when the car is started and gradually reduces choke

and idle. Additionally, at several temperature thresholds,

thermally controlled valves apply vacuum to diaphragm-type

actuators to reduce idle speed and choke more quickly than the

thermostatic spring alone. On the fuel-injected (LX, LX-i) models,

fast idle is controlled by the fast idle valve which shunts air

around the throttle, giving the same effect as opening the

throttle. The fast idle valve is a wax-type valve similar to the

cooling system thermostat and is arranged to provide maximum air

when cold and none when fully warmed up (is warmed by passages

through which engine coolant flows). By way of the engine's other

various sensors the computer (ECU) is informed of the increased

airflow and adds more fuel via the injectors to maintain correct

fuel-air ratio during fast idle. Drew


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