Idle speed control system (Mazda Capella GD)

The idle speed control system mainly consists of an air valve and a solenoid-actuated air bleed valve. The air valve is heated by a bimetallic plate and a heating coil and takes over the function of accelerating idle speed by increasing air intake through the throttle bypass valve while the engine is cold. This limits the engine warm-up time at idle speed. Other parts associated with this system include the atmospheric pressure sensor (sends appropriate signals to the engine control unit), intake air temperature sensor (built into the air flow meter), pneumatic power steering switch (turns on when the steering gear is turned left or right).

6.2.1. Possible works

In order to check the operating mode of the air valve, you need to put the hose shown in the figure on the air valve (16) figure 139, clamp with pliers (wrap the hose with a rag), after the engine has been started.

If the engine is cold, the speed should be limited, but if the engine is warm, it should not drop below 200 rpm.

If the RPM does not decrease when the engine is cold, the air valve is faulty or the heat protection valve is leaking.

If the drop in speed when warm is more than 200 rpm, the problem is in the air valve or in the current supply to the valve. All other work should be left to be done at a workshop.