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Engine - Intake-Air System: Diagnosis Mazda MX-5 NC

Mechanical 5 illustrations ~370 words

INTAKE MANIFOLD VACUUM INSPECTION [LF]

  1. Verify that the intake air hoses are installed securely.
  2. Disconnect the vacuum hose connecting the intake manifold and the purge solenoid valve (purge solenoid valve side) and install the vacuum gauge.
  3. Warm up the engine.
  4. Measure the intake manifold vacuum while idling (no load) using the vacuum gauge. If not within the specification, perform the following inspections. Compression pressure (See «COMPRESSION INSPECTION [LF]»(ref-244453-S01263720752006092400000) .) Air intake Each hose installation part Throttle body installation part Fuel injector installation part PCV valve installation part Dynamic chamber installation port Intake manifold installation part Standard -60 kPa {-450 mmHg, -17.7 inHg} or more

AIR CLEANER ELEMENT INSPECTION [LF]

  1. Remove the air cleaner element. (See «INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [LF]»(ref-244455-S24513161252006092400000) .)
  2. Inspect the following items: If there is any abnormality, clean or replace the air cleaner element. Has the replacement interval come? Is the air cleaner element soiled, damaged, or bent? Are the air cleaner case and the air cleaner element correctly sealed? Is the correct air cleaner element installed?

THROTTLE BODY INSPECTION [LF]

Note. Perform the following inspection only when directed.

Resistance Inspection

  1. Remove the battery cover.
  2. Disconnect the negative battery cable. (See «BATTERY REMOVAL/INSTALLATION [LF]»(ref-244448-S25513985422006092400000) .)
  3. Disconnect the throttle body connector.
  4. Measure the resistance between throttle actuator terminals A and B. If not as specified, replace the throttle body. (See «INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [LF]»(ref-244455-S24513161252006092400000) .) If as specified, carry out the «Circuit Open/Short Inspection»(ref-244455-S15665429092006092400000) .

Specification

Ambient temperature (°C {°F})Resistance (ohm)
Approx. 20 {68}0.3-100

AMBIENT TEMPERATURE SPECIFICATION

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5: Circuit Open/Short Inspection
Scheme 5: Circuit Open/Short Inspection
  1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [LF]»(ref-244452-S11022070362006092400000) .)
  2. Inspect the following wiring harnesses for open or short (continuity check).

VARIABLE INTAKE AIR SOLENOID VALVE INSPECTION [LF]

Note. Perform the following inspection only when directed.

Scheme 6

Scheme 6: Airflow Inspection
Scheme 6: Airflow Inspection

Scheme 7

Scheme 7
Scheme 7
  1. Remove the battery cover
  2. Disconnect the negative battery cable. (See «BATTERY REMOVAL/INSTALLATION [LF]»(ref-244448-S25513985422006092400000) .)
  3. Remove the variable intake air solenoid valve. (See «VARIABLE INTAKE AIR SOLENOID VALVE REMOVAL/INSTALLATION [LF]»(ref-244455-S18172773442006092400000) .)
  4. Inspect airflow between the ports under the following conditions. If not as specified, replace the variable intake air solenoid valve. If as specified, carry out the «Circuit Open/Short Inspection»(ref-244455-S04936045092006092400000) .

Scheme 8

Scheme 8: Circuit Open/Short Inspection
Scheme 8: Circuit Open/Short Inspection
  1. Disconnect the PCM connector. (See «PCM REMOVAL/INSTALLATION [LF]»(ref-244452-S11022070362006092400000) .)
  2. Inspect the following wiring harness for open or short (continuity check).

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