NO.21 ENGINE NOISE [MZR 1.6]

id0103f9802700

21

ENGINE NOISE

DESCRIPTION

•  The engine noise from under bonnet.

POSSIBLE CAUSE

Squeal, click or chirp noise:

•  Improper drive belt tension

•  Improper engine oil level

•  Generator installation (alignment)

•  Splash shield or under cover looseness (splashed water to drive belt)

Rumble or grind noise:

•  Improper drive belt tension

Rattle sound noise:

•  Loose parts

Hiss sound noise:

•  Air leakage from intake-air system

•  Loose spark plug

•  Vacuum leakage

Rap or roar sound noise:

•  Dynamic damper looseness

•  Exhaust system looseness

•  Intake-air system looseness

Other noise:

•  Tappet noise

•  Timing chain noise

•  PCM malfunction

21	ENGINE NOISE
DESCRIPTION	• The engine noise from under bonnet.
POSSIBLE CAUSE	Squeal, click or chirp noise: • Improper drive belt tension • Improper engine oil level • Generator installation (alignment) • Splash shield or under cover looseness (splashed water to drive belt) Rumble or grind noise: • Improper drive belt tension Rattle sound noise: • Loose parts Hiss sound noise: • Air leakage from intake-air system • Loose spark plug • Vacuum leakage Rap or roar sound noise: • Dynamic damper looseness • Exhaust system looseness • Intake-air system looseness Other noise: • Tappet noise • Timing chain noise • PCM malfunction

Diagnostic Procedure

STEP	INSPECTION	ACTION
1	Is a squealing, click or chirping sound present?	Yes	Inspect the following: • Drive belt tension • Engine oil • Generator installation (alignment) • Splash shield or under cover looseness Repair or replace the malfunctioning part according to the inspection results.
1	Is a squealing, click or chirping sound present?	No	Go to the next step.
2	Is a rumbling or grinding sound present?	Yes	Inspect the drive belt. (See DRIVE BELT INSPECTION [MZR 1.6].) Replace the drive belt, if necessary. (See DRIVE BELT REMOVAL/INSTALLATION [MZR 1.6].)
2	Is a rumbling or grinding sound present?	No	Go to the next step.
3	Is a rattling sound present?	Yes	Inspect the rattling location for loose parts. Repair or replace the malfunctioning part according to the inspection results.
3	Is a rattling sound present?	No	Go to the next step.
4	Is a hissing sound present?	Yes	Inspect the following: • Intake-air system leakage • Spark plug looseness • Vacuum leakage Repair or replace the malfunctioning part according to the inspection results.
4	Is a hissing sound present?	No	Go to the next step.
5	Is a rapping or roaring sound present?	Yes	Inspect the following for looseness: • Dynamic chamber • Exhaust system • Intake-air system Repair or replace the malfunctioning part according to the inspection results.
5	Is a rapping or roaring sound present?	No	Go to the next step.
6	Is a knocking sound present?	Yes	Go to the symptom troubleshooting “NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE”. (See NO.13 KNOCKING/PINGING-ACCELERATION/CRUISE [MZR 1.6].)
6	Is a knocking sound present?	No	If the noise comes from engine internal: • Inspect for timing chain or tappet noise. • Repair or replace the malfunctioning part according to the inspection results. (See TIMING CHAIN REMOVAL/INSTALLATION [MZR 1.6].)
7	Verify the test results. • If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 1.6].) • If malfunction remains, inspect related Service information perform repair or diagnosis. ― If vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.6].)