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2008 - MX-5 - Engine

NO.15 EMISSION COMPLIANCE [LF]



15

EMISSION COMPLIANCE

DESCRIPTION

Fails emissions test.

POSSIBLE CAUSE

  • Vacuum lines leakage or blockage

  • Cooling system malfunction

  • Spark plug malfunction

  • Leakage from intake manifold

  • Erratic or no signal from CMP sensor

  • Inadequate fuel pressure

  • PCV valve malfunction or incorrect valve installation

  • EGR valve malfunction

  • Exhaust system clogging

  • Fuel tank ventilation system malfunction

  • Fuel-filler cap malfunction

  • Charcoal canister damage

  • Air cleaner element clogging or restriction

  • Throttle body malfunction

  • Erratic signal to ignition coil

  • Improper air/fuel mixture ratio control operation

  • Bend or open circuit HO2S wiring harness

  • Catalyst converter malfunction

  • Engine internal parts malfunction

  • Excessive carbon is built up in combustion chamber

  • Improper engine compression

  • Improper valve timing

WARNING:

The following troubleshooting flow chart contains fuel system diagnosis and repair procedures. Read following warnings before servicing fuel system:
  • Fuel vapor is hazardous. It can easily ignite, causing serious injury and damage. Always keep sparks and flames away from fuel.

  • Fuel line spills and leakage are dangerous. Fuel can ignite and cause serious injuries or death and damage. Fuel can also irritate skin and eyes. To prevent this, always complete “BEFORE SERVICE PRECAUTION” and “AFTER SERVICE PRECAUTION” described in this manual.

    (See BEFORE SERVICE PRECAUTION [LF].)

    (See AFTER SERVICE PRECAUTION [LF].)

CAUTION:

  • Disconnecting/connecting quick release connector without cleaning it may cause damage to fuel pipe and quick release connector. Always clean quick release connector joint area before disconnecting/connecting, and make sure that it is free of foreign material.


Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1

Inspect for the following:

  • Vacuum lines for leakage or blockage

  • Electrical connections

  • Proper maintenance schedule followed

  • Intakeā€air system and air cleaner element concerns: obstructions, leakage or dirtiness

Are all items normal?

Yes

Go to the next step.

No

Service if necessary.

Repeat Step 1.

2

Connect the M-MDS to the DLC-2.

Turn the ignition switch to the ON position (Engine off).

Retrieve any DTCs.

Are there any DTCs displayed?

Yes

DTC is displayed:

Go to appropriate DTC inspection.

(See DTC TABLE [LF].)

No

No DTC is displayed:

Go to the next step.

3

Is any other driveability concern present?

Yes

Go to appropriate symptom troubleshooting.

No

Go to the next step.

4

Connect the M-MDS to the DLC-2.

Access ECT PID.

Warm up the engine and idle it.

Verify ECT PID is correct.

(See PCM INSPECTION [LF].)

Is ECT PID correct?

Yes

Go to the next step.

No

Inspect for coolant leakage, cooling fan and condenser fan operation or thermostat operation.

5

Inspect fuel-filler cap.

(See FUEL-FILLER CAP INSPECTION [LF].)

Is there any leakage at fuel-filler cap?

Yes

Replace the fuel-filler cap.

No

Go to the next step.

6

Inspect the front HO2S.

(See FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION [LF].)

Is front HO2S normal?

Yes

Go to the next step.

No

Replace the front HO2S.

(See FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [LF].)

7

Perform spark test.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF].)

Is strong blue spark visible at each cylinder?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part according to spark test result.

8

Install the fuel pressure gauge between the fuel pipe and the fuel distributor.

Start the engine and idle it.

Measure fuel line pressure during idle.

Is fuel line pressure correct during idle?

(See FUEL LINE PRESSURE INSPECTION [LF].)

Yes

Go to the next step.

No

Low:

Inspect the fuel line for clogging.

If there is no malfunction, replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF].)

High:

Replace the fuel pump unit.

(See FUEL PUMP UNIT REMOVAL/INSTALLATION [LF].)

9

Remove and shake the PCV valve.

Does the PCV valve rattle?

Yes

Go to the next step.

No

Replace the PCV valve.

10

Inspect for fuel saturation inside charcoal canister.

Is excess amount of liquid fuel present in canister?

Yes

Replace the charcoal canister.

No

Inspect the fuel tank vent system.

Then, go to the next step.

(See FUEL TANK INSPECTION [LF].)

11

visually inspect the exhaust system part.

Is there any deformed exhaust system part?

Yes

Replace the part.

No

Go to the next step.

12

Inspect the three-way catalytic converter.

(See EXHAUST SYSTEM INSPECTION [LF].)

Is the three-way catalytic converter normal?

Yes

Inspect the EGR system.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [LF].)

No

Replace the three-way catalytic converter.

13

  • Verify test results.

    • If normal, return to diagnostic index to service any additional symptoms.

      (See SYMPTOM DIAGNOSTIC INDEX [LF].)

    • If malfunction remains, inspect related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.

      • If vehicle is repaired, troubleshooting completed.

      • If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.

        (See PCM REMOVAL/INSTALLATION [LF].)




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