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Home >> Mazda >> 2006 >> 6 s, 4D Wagon, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Symptom Troubleshooting [Engine Control System L3)) >> No. 19 Exhaust Smoke >> Diagnostic procedure

Diagnostic procedure

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DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 What color is smoke coming from exhaust system? Blue Burning oil is indicated.
Go to the next step.
White Water in combustion is indicated.
Go to Step 3.
Black Rich fuel mixture is indicated.
Go to Step 4.
2 Remove and shake PCV valve.
Does PCV valve rattle?
Yes Inspect for the following:
  • Damaged valve guide, stems or valve seals
  • Blocked oil drain passage in cylinder head
  • Piston ring is not seated, seized or worn.
  • Damaged cylinder bore

If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
No Replace PCV valve.
3 Does cooling system hold pressure? Yes Inspect for the following:
  • Cylinder head gasket leakage
  • Intake manifold gasket leakage
  • Cracked or porous engine block

If other driveability symptoms are present, return to diagnostic index to service any additional symptoms.
No Inspect for cause.
4 Inspect for the following:
  • Air cleaner restriction
  • Collapsed or restricted intake-air system
  • Restricted fuel return line

Are all items normal?
Yes Go to the next step.
No Service if necessary.
Repeat Step 4.
5 Connect WDS or equivalent to DLC-2.
Turn ignition switch to ON position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?
Yes DTC is displayed: 
Go to appropriate DTC test.
No No DTC is displayed: 
Go to the next step.
6 Install fuel pressure gauge between fuel pipe and fuel distributor.
Start engine and idle it.
Measure fuel line pressure during idle.
Is fuel line pressure correct during idle?
(See FUEL LINE PRESSURE INSPECTION ).
Yes Go to the next step.
No Zero or low: 
  • Inspect for clogged fuel line.
  • If okay, replace fuel pump unit.

High: 
  • Replace fuel pump unit.
7 Perform Spark Test.
(See SPARK TEST ).
Is the strong blue spark visible at each cylinder?
Yes Inspect spark plugs and CMP sensor.
No Repair or replace malfunctioning part according to spark test results.
8 Verify test results.
  • If okay, return to diagnostic index to service any additional symptoms.
  • 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, reprogram PCM if later calibration is available. Retest.