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2014 - Mazda6 - Engine

NO.25 EXHAUST SULPHUR SMELL [SKYACTIV-G 2.5]



25

EXHAUST SULPHUR SMELL

DESCRIPTION

  • Rotten egg smell (sulphur) from exhaust.

POSSIBLE CAUSE

  • Electrical connectors are disconnected or connected poorly

  • Vacuum lines are disconnected or connected improperly.

  • Poor fuel quality

  • PCM DTC is stored

  • Inadequate fuel pressure

    • Fuel pressure sensor malfunction

    • High pressure fuel pump malfunction

    • Spill valve control solenoid valve control circuit malfunction (damage to driver in PCM caused by short circuit to ground system)

    • Spill valve control solenoid valve (built-into high pressure fuel pump) malfunction

    • Relief valve (built-into high pressure fuel pump) malfunction

    • Fuel line restricted

    • Fuel pump unit malfunction

  • Charcoal canister malfunction

  • Fuel tank vent system malfunction

WARNING:

The following troubleshooting flow chart contains the fuel system diagnosis and repair procedures. Read the following warnings before performing the fuel system services:

  • 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 injury 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 [SKYACTIV-G 2.5].) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5].)

CAUTION:

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

CAUTION:

Related PIDs

Item (definition)

Unit/Condition

Definition

Condition/Specification (Reference)

FUEL_PRES

KPa {MPa}, mBar {Bar}, psi, in H20

Fuel pressure

  • Displays fuel pressure

V

  • Fuel pressure is 3.0 MPa {31 kgf/cm2, 435 psi}: Approx. 0.92 V

  • Fuel pressure is 4.8 MPa {49 kgf/cm2, 696 psi}: Approx. 1.17 V

LOAD

%

Engine load

  • Idle (after warm up): Approx. 17.64%

  • Racing (engine speed is 2,000 rpm): Approx. 14.51%

  • Racing (engine speed is 4,000 rpm): Approx. 21.17%

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION

1

 VERIFY IF THERE IS POOR DRIVEABILITY OR EXHAUST GAS RELATED MALFUNCTION

  • Are any driveability or exhaust smoke concerns present?

Yes

Go to the applicable symptom troubleshooting.

(See SYMPTOM DIAGNOSTIC INDEX [SKYACTIV-G 2.5].)

No

Go to the next step.

2

 INSPECT RELATED PART CONDITION

  • Inspect the following:

    • Electrical connections

    • Vacuum lines

    • Fuel quality

  • Is there any malfunction?

Yes

Service if necessary.

  • Repeat this step.

No

Go to the next step.

3

 VERIFY PCM DTC

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [SKYACTIV-G 2.5].)

No

Go to the next step.

4

 INSPECT FUEL PRESSURE (HIGH-SIDE)

  • Start the engine and warm it up completely.

  • Access the FUEL_PRES PID using the M-MDS at idle.

    (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].)

  • Is the FUEL_PRES PID value approx. 3 MPa {31 kgf/cm2, 435 psi}?

Yes

Go to Step 8.

No

Lower than 3 MPa {31 kgf/cm2, 435 psi}:

Higher than 3 MPa {31 kgf/cm2, 435 psi}:

  • Go to the next step.

5

 DETERMINE IF MALFUNCTION CAUSE IS FUEL PRESSURE SENSOR OR HIGH PRESSURE FUEL PUMP

  • Is the vehicle acceleration performance normal?

Yes

Go to the next step.

No

Go to Step 7.

6

 INSPECT FUEL PRESSURE SENSOR

Yes

Replace the fuel distributor.

(See FUEL INJECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

No

Go to Step 8.

7

 INSPECT SPILL VALVE CONTROL SOLENOID VALVE CONTROL CIRCUIT FOR SHORT TO GROUND

  • Switch the ignition off.

  • Disconnect the high pressure fuel pump and PCM connectors.

  • Inspect for continuity between high pressure fuel pump terminal A (wiring harness-side) and body ground.

  • Is there continuity?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between high pressure fuel pump terminal A and PCM terminal 1EE.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to ground.

If the malfunction remains:

No

Replace the high pressure fuel pump.

(See HIGH PRESSURE FUEL PUMP REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

8

 INSPECT FUEL PRESSURE (LOW-SIDE)
    Specification:

  • 405—485 kPa {4.13—4.94 kgf/cm2, 58.8—70.3 psi}

Yes

Go to the next step.

No

Inspect the following:

  • Fuel line restriction

  • Fuel filter clogged

9

 DETERMINE IF MALFUNCTION CAUSE IS CHARCOAL CANISTER OR FUEL TANK VENT SYSTEM

Yes

Replace the charcoal canister.

(See CHARCOAL CANISTER REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

No

Inspect the fuel tank vent system.

  • If the fuel tank vent system is normal:

    • Suggest trying a different brand since sulfur content can vary in different fuels.

  • If fuel tank vent system is not normal:

    • Repair or replace the malfunctioning part according to the inspection results.

10

Verify the test results.

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

    (See SYMPTOM DIAGNOSTIC INDEX [SKYACTIV-G 2.5].)

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

    • If the vehicle is repaired, troubleshooting is completed.

    • If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.



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