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Home >> Mazda >> 1990 >> 929 V6-3.0L DOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Idle Speed/Throttle Actuator - Electronic >> Testing and Inspection
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Idle Speed/Throttle Actuator - Electronic: Testing and Inspection

SYSTEM OPERATION
1. Start the engine and run it at idle.





2. Disconnect the ISC valve connector.
3. Verify that the engine speed decreases.





4. Check air valve operation.
Pinch the air hose to the BAC valve as shown and verify that the engine speed decreases.
5. Connect the ISC valve connector.


BYPASS AIR CONTROL (BAC) VALVE

ISC Valve Inspection




1. Disconnect the ISC valve connector.





2. Connect an ohmmeter to the terminals of the ISC valve.
3. Check the resistance.

Resistance (at 20°C [68°F]): 1O.7 - 12.3 Ohms

4. If not as specified, replace the BAC valve.



ISC Valve Removal/Installation




1. Disconnect the ISC valve connector.
2. Disconnect the water hoses and the air hose.
3. Remove the BAC valve and the gasket.





4. Install in the reverse order of removal.


Air Valve Inspection




1. Blow air through the valve from port A and verify that air comes out of port B when the BAC valve is cold.
2. Place the BAC valve into hot water (more than 80°C [17609) for one minute.
3. Blow air through the valve from port A and verify that no air comes out of port B.
4. If not correct, replace the BAC valve.


Air Valve Installation




1. Remove any dirt or old sealant from the contact surfaces.
2. Install the gasket and the BAC valve.

Tightening torque: 7.8 - 11 Nm (80 - 110 cm-kg, 69 - 95 in-lb)

Caution: Use a new gasket.

3. Connect the water hoses, the air hose and the ISC valve connector.


Idle Speed Inspection
1. Warm up the engine to normal operating temperature.
2. Turn all electric loads OFF.




3. Connect a jumper wire between the test connector (Green: 1-pin) and a ground.
4. Verify that the idle speed is within specification.

Idle speed: 700 ± 20 rpm (P range)





5. If the idle speed is not within specification, adjust the idle by turning the air adjusting screw.
6. After checking the idle speed, disconnect the jumper wire from the test connector.
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