NO.21 ENGINE NOISE [SKYACTIV-G 2.5T]

id0103q4802700

21

ENGINE NOISE
DESCRIPTION
•  Engine noise from under bonnet.
POSSIBLE CAUSE
Buzzing sound is heard from exhaust pipe during cold engine start:
Note
•  During a cold engine start, sound occurs for up to approx. 30 s with fast idle up for a drive-by-wire control and the warm-up promotion spark retard correction for ignition timing control.
•  Sound occurs from drive-by-wire control, ignition control (vehicle is normal)
•  Dynamic damper loose
•  Exhaust system installation condition
•  Intake system installation condition
Squeal, click, or chirp noise:
•  Improper engine oil level
•  Loose installation of solenoid valves
•  Improper drive belt tension
•  Generator installation
•  Auto tensioner bearing malfunction
•  Splash shield or under cover loose (splash water to drive belt)
Thumping/rattling or creaking sound noise:
•  Improper drive belt tension
•  Loose parts
•  Loose fitting heater hoses vibrating the heater hose bracket protector
Hissing sound noise:
•  Vacuum leakage
•  Loose spark plug
•  Air leakage from the intake-air system
Clattering noise:
•  Loose parts
Lightly tapping or rumbling noise:
•  Dynamic damper loose
•  Exhaust system loose
•  Intake-air system loose
Excessive noise from turbocharger:
•  Foreign objects or material in the compressor inlet to the intake manifold ducting or the compressor housing
•  Carbon built-up in the turbine housing
•  Turbocharger routing assembly banding or dragging
•  Loose intake or exhaust ducting systems
Other noise:
•  Electric variable valve timing actuator malfunction
•  Hydraulic variable valve timing actuator malfunction
•  Timing chain noise
•  Hydraulic lash adjuster (HLA) noise
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.
?  Highly pressurized fuel may spray out if the fuel line is cut. Due to the following dangers occurring with a fuel spray, always complete the “Fuel Line Safety Procedure” to prevent the fuel from spraying. (See BEFORE SERVICE PRECAUTION [SKYACTIV-G 2.5T].)
•  Fuel may cause irritation if it comes in contact with skin and eyes.
•  If fuel ignites and causes a fire, it may lead to serious injury or death, and damage to property and facilities.
?  Fuel is highly flammable and dangerous. Fuel line spills and leakage can cause serious injury or death, and damage to equipment. Always refer to the “Quick Release Connector Removal/Installation (fuel system)” before performing the fuel hose installation, and execute the “Fuel Leakage Inspection” after installation. (See QUICK RELEASE CONNECTOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.5T].)
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 material.

Diagnostic Procedure

STEP

INSPECTION

RESULTS

ACTION
1
VERIFY SYMPTOM
•  Verify the occurring sound.
—
Buzzing sound is heard from exhaust pipe during cold engine start:
•  Go to the next step.
Squeal, click, or chirp sound is heard:
•  Go to Step 3.
Thumping/rattling or creaking sound is heard:
•  Go to Step 4.
Hissing sound is heard:
•  Go to Step 5.
Clattering sound is heard:
•  Go to Step 6.
Lightly tapping or rumbling sound is heard:
•  Go to Step 7.
Excessive noise from turbocharger:
•  Go to Step 8.
Other noise is heard:
•  Go to Step 10.
2
BUZZING SOUND IS HEARD FROM EXHAUST PIPE DURING COLD ENGINE START
•  Verify the sound from the exhaust pipe during a cold engine start.
•  Does the sound disappear after approx. 30 s have elapsed?
Yes
Note
•  During a cold engine start, sound occurs for up to approx. 30 s with fast idle up for a drive-by-wire control and the warm-up promotion spark retard correction for ignition timing control.
Go to Step 9 because the operation is normal.
No
Inspect the following:
•  Exhaust system installation condition
•  Intake system installation condition
?  If there is any malfunction:
•  Repair or replace the malfunctioning part according to the inspection results.
?  If there is no malfunction:
•  Go to Step 12.
3
VERIFY IF THERE IS SQUEAL, CLICK, OR CHIRP SOUND
•  Inspect the following:
?  Engine oil level
?  Solenoid valves installation
?  Drive belt tension
?  Generator installation
?  Auto tensioner bearing damaged
?  Splash shield or under cover loose
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to Step 12.
4
VERIFY IF THERE IS THUMPING/RATTLING OR CREAKING SOUND
•  Inspect the following:
?  Drive belt tension
?  Loose parts in engine compartment
?  Loose fitting heater hoses vibrating the heater hose bracket protector
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to Step 12.
5
VERIFY IF THERE IS HISSING SOUND
•  Inspect the following:
?  Vacuum leakage
?  Spark plug loose
?  Intake-air system leakage
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to Step 12.
6
VERIFY IF THERE IS CLATTERING SOUND
•  Inspect the location of rattle for loose parts.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to Step 12.
7
VERIFY IF THERE IS LIGHTLY TAPPING OR RUMBLING SOUND
•  Inspect the following:
?  Exhaust system installation condition
?  Intake system installation condition
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to Step 12.
8
VISUALLY INSPECT THE TURBOCHARGER
•  Remove the parts necessary to inspect the turbocharger without removing the turbocharger.
•  Inspect if the turbocharger compressor wheel is bent, damaged, or interfering with housing on vehicle.
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
No
Go to next Step.
9
VISUALLY INSPECT THE TURBINE HOUSING
•  Visually inspect the turbine housing.
•  Is there any carbon built-up or foreign material on the turbine housing?
Yes
Clean built-up carbon or remove foreign materials.
•  If turbine housing damaged:
?  Replace the dynamic pressure turbo.
No
Replace the intake air system.
(See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [SKYACTIV-G 2.5T].)
10
VERIFY IF THERE IS KNOCK SOUND
•  Is knocking noise present?
Yes
Perform the symptom troubleshooting “NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE”.
(See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [SKYACTIV-G 2.5T].)
No
If noise comes from engine internal:
•  Inspect the following:
?  Timing chain
?  Hydraulic lash adjuster (HLA) noise
?  Electric variable valve timing actuator
?  Hydraulic variable valve timing actuator
?  Engine compression
•  Repair or replace the malfunctioning part according to the inspection results.
11
Verify the test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If a malfunction remains, inspect the related Service Information and perform the repair or diagnosis.
?  If the vehicle is repaired, troubleshooting is completed.
?  If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM.