21

ENGINE NOISE

DESCRIPTION

• Engine noise from under hood.

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)

Rattling or creaking sound noise:

• Improper drive belt tension

• Loose parts

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

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 2.0].)

• 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 2.0].) (See AFTER SERVICE PRECAUTION [SKYACTIV-G 2.0].)

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.

STEP

INSPECTION

RESULTS

ACTION

1

• Verify the occurring sound.

—

Buzzing sound is heard from exhaust pipe during cold engine start:

• Go to Step 2.

Squeal, click, or chirp sound is heard:

• Go to Step 3.

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.

Other noise is heard:

• Go to Step 8.

2

• 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 9.

3

• 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 9.

4

• Inspect the following:

• Drive belt tension

• Loose parts in engine compartment

• Is there any malfunction?

Yes

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

No

Go to Step 9.

5

• 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 9.

6

• 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 9.

7

• 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 9.

8

• Is knocking noise present?

Yes

Perform the symptom troubleshooting “NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE”.

(See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [SKYACTIV-G 2.0].)

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.

9

Verify the test results.

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

  (See SYMPTOM DIAGNOSTIC INDEX [SKYACTIV-G 2.0].)

• 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.