compression ratio SUBARU FORESTER 2004 Service Owner's Manual

ME(H4DOTC)-123
MECHANICAL
Engine Noise
26.Engine Noise
A: INSPECTION
NOTE*:
When disconnecting the fuel injector connector, Malfunction Indicator Light illuminates and DTC is stored in
ECM memory.
Therefore, carry out the CLEAR MEMORY MODE Mode.> and INSPECTION MODE after con-
necting the fuel injector connector.
Type of sound Condition Possible cause
Regular clicking soundSound increases as engine
speed increases. Valve mechanism is defective.
 Incorrect valve clearance
 Worn valve rocker
 Worn camshaft
 Broken valve spring
Heavy and dull clankOil pressure is low. Worn crankshaft main bearing
 Worn connecting rod bearing (big end)
Oil pressure is normal. Loose flywheel mounting bolts
 Damaged engine mounting
High-pitched clank (Spark
knock)Sound is noticeable when
accelerating with an overload. Ignition timing advanced
 Accumulation of carbon inside combustion chamber
 Wrong heat range of spark plug
 Improper octane number of gasoline
Clank when engine speed is
medium (1,000 to 2,000 rpm).Sound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*) Worn crankshaft main bearing
 Worn bearing at crankshaft end of connecting rod
Knocking sound when engine
is operating under idling speed
and engine is warmSound is reduced when fuel
injector connector of noisy cyl-
inder is disconnected.
(NOTE*) Worn cylinder liner and piston ring
 Broken or stuck piston ring
 Worn piston pin and hole at piston end of connecting rod
Sound is not reduced if each
fuel injector connector is dis-
connected in turn. (NOTE*) Unusually worn valve lifter
 Worn cam gear
 Worn camshaft journal bore in crankcase
Squeaky sound —  Insufficient generator lubrication
Rubbing sound —  Defective generator brush and rotor contact
Gear scream when starting
engine— Defective ignition starter switch
 Worn gear and starter pinion
Sound like polishing glass with
a dry cloth— Loose drive belt
 Defective water pump shaft
Hissing sound — Loss of compression
 Air leakage in air intake system, hoses, connections or mani-
folds
Timing belt noise — Loose timing belt
 Belt contacting case/adjacent part
Valve tappet noise —  Incorrect valve clearance

EN(H4DOTC)-168
ENGINE (DIAGNOSTIC)
Diagnostic Procedure with Diagnostic Trouble Code (DTC)
12 CHECK FUEL LEVEL.Is the fuel meter indication
higher than the “Lower” level?Go to step 13.Replenish fuel so
fuel meter indica-
tion is higher than
the “Lower”
level.After replen-
ishing fuel, Go to
step 13.
13 CHECK STATUS OF MALFUNCTION INDI-
CATOR LIGHT.
1) Clear the memory using Subaru Select
Monitor.
Mode.>
2) Start the engine, and drive the vehicle more
than 10 minutes.Does the malfunction indicator
light illuminate or blink?Go to step 15.Go to step 14.
14 CHECK CAUSE OF MISFIRE DIAGNOSED.Was the cause of misfire diag-
nosed when the engine is run-
ning?Finish diagnostics
operation, if the
engine has no
abnormality.Repair the poor
contact.
N
OTE:
In this case repair
the following:
 Poor contact in
ignition coil con-
nector
 Poor contact in
fuel injector con-
nector on faulty
cylinders
 Poor contact in
ECM connector.
 Poor contact in
coupling connector
15 CHECK AIR INTAKE SYSTEM.Is there any fault in air intake
system?Repair air intake
system.
N
OTE:
Check the follow-
ing items:
 Are there air
leaks or air suction
caused by loose or
dislocated nuts
and bolts?
 Are there cracks
or any disconnec-
tion of hoses?Go to step 16.
16 CHECK CYLINDER.Is there a fault in that cylinder? Repair or replace
the faulty par t.
N
OTE:
Check the follow-
ing items:
 Spark plug
 Fuel injector
 CompressionGo to DTC P0171
and P0172. to EN(H4DOTC)-
148, DTC P0171
SYSTEM TOO
LEAN (BANK 1),
Diagnostic Proce-
dure with Diagnos-
tic Trouble Code
(DTC).> Step Check Yes No