After ensuring air pump and all hoses are correct, check carburetor and air control valve attaching nuts for tightness. Warm engine to normal operating temperature. Stop engine and connect a tachometer.
Disconnect air cleaner-to-air control valve hose at air cleaner. Place a finger over the hose opening. Increase the engine speed and make sure that air flows out when engine speed reaches 1500-2500 RPM for non-turbo model or 3850 RPM for turbo model. See Fig 1 .
Run the engine at idling speed. Disconnect the vacuum hose connecting relief solenoid valve to air control valve at the air control valve. Air should flow out from the air hose. Reconnect the vacuum hose and the air hose.
Disconnect the split air hose (from check valve to intake manifold) at the intake manifold. Place a finger over the port opening. Disconnect the vacuum hose connecting switching solenoid to air control valve at the air control valve.
Air should flow out from the port. Reconnect the vacuum hose and split air hose. If air control valve does not respond as described, replace air control valve.

Fig 1: Checking Air Control Valve

Courtesy of MAZDA MOTORS CORP.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Air Control Valve