NO.15 EXCESSIVE BLACK SMOKE [WLT-1, WLT-2]

id010396913500

15
Excessive black smoke
DESCRIPTION
•  Excessive black smoke is observed in the exhaust gas.
POSSIBLE CAUSE
•  Air cleaner element restriction
•  Incorrect fuel injection timing
•  Injection nozzle malfunction
•  FIP malfunction
•  Low engine compression
•  EGR System Malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
•  Does any other symptom exist?
Yes
Go to the appropriate flow chart.
No
Go to the next step.
2
•  Inspect the air cleaner element for clogging.
•  Is the air cleaner element normal?
Yes
Go to the next step.
No
Repair or replace the air cleaner element.
3
•  Inspect the injection timing.
•  Is the injection timing normal?
Yes
Go to the next step.
No
Inspect the TCV.
(See TIMER CONTROL VALVE (TCV) INSPECTION [WLT-1, WLT-2].)
If the TCV is normal, adjust the injection timing.
4
•  Remove the injection nozzle.
•  Inspect the injection nozzle for the following:
―  Clogged nozzle
―  Seized needle valve
―  Incorrect valve opening pressure
―  Malfunctioning nozzle gasket
•  Is the injection nozzle normal?
Yes
Go to the next step.
No
Clogged nozzle or seized needle valve:
•  Disassemble and clean or replace the injection nozzle.
Incorrect valve opening pressure:
•  Adjust injection nozzle opening pressure.
Malfunctioning nozzle gasket:
•  Replace nozzle gasket.
5
Note
•  The following test should be performed on vehicles with EGR system. Go to next step for vehicles without EGR system.
•  Carry out EGR system inspection.
•  Is the EGR system normal?
Yes
Go to the next step.
No
Repair or replace as necessary.
6
•  Measure the engine compression.
•  Is the compression normal?
Yes
Inspect the following:
•  Boost sensor
•  Injection pump
No
Inspect the following:
•  Damaged valve seat
•  Worn valve stem and valve guide
•  Worn or stuck piston ring
•  Worn piston, piston ring or cylinder
Service if necessary.
7
•  Verify the test results. If normal, return to the diagnostic index to service any additional symptoms.