System Inspection

Operate engine to warm temperature. Turn engine off. On turbo models, remove intercooler. On all models, disconnect intake air temperature sensor.
Install resistor at temperature sensor terminals. On non-turbo models, install 2000-3000-ohm resistor or 3500-ohm resistor on turbo models. See Fig 1 .

Fig 1: Installing Intake Air Temperature Sensor Resistor
Courtesy of MAZDA MOTORS CORP.
Install tachometer. Start engine and note engine RPM. Engine RPM must be at specified RPM for proper amount of time and then decrease. See ENGINE RPM SPECIFICATIONS table.
Shut engine off. On non-turbo models, disconnect pressure regulator hose. See Fig 2 . Place finger over end of vacuum hose. Start engine. Check that no vacuum exists for 90 seconds after engine is started and then exists after 90 seconds.

Fig 2: Removing Pressure Regulator Hose (Non-Turbo Models)
Courtesy of MAZDA MOTORS CORP.
On turbo models, connect voltmeter to pressure regulator control solenoid valve. See Fig 3 . Start engine and note voltage. Voltage should be below 2 volts for 50 seconds after engine is started, then increase to approximately 12 volts after 50 seconds.

Fig 3: Connecting Voltmeter On Regulator Solenoid Valve

Courtesy of MAZDA MOTORS CORP.