Subaru Legacy (2005 year). Manual — part 288

ME(H4DOTC)-95

MECHANICAL

Engine Trouble in General

2. Rough idle and engine
stall

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Intake system

Loosened or cracked intake duct

A

Loosened or cracked PCV hose

A

Loosened or cracked vacuum hose

A

Defective intake manifold gasket

B

Defective throttle body gasket

B

Defective PCV valve

C

Loosened oil filler cap

B

Dirty air cleaner element

C

Fuel line

Defective fuel pump and relay

C

Clogged fuel line

C

Lack of or insufficient fuel

B

Belt

Defective timing

C

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

B

Loosened cylinder head bolt or defective gasket

B

Improper valve sealing

B

Defective valve stem

C

Worn or broken valve spring

B

Worn or stuck piston rings, cylinder and piston

B

Incorrect valve timing

A

Improper engine oil (low viscosity)

B

Lubrication system

Incorrect oil pressure

B

Defective rocker cover gasket

C

Cooling system

Overheating

C

Other

Evaporative emission control system malfunction

A

Stuck or damaged throttle valve

B

Symptom

Problem parts, etc.

Possible cause

Rank

ME(H4DOTC)-96

MECHANICAL

Engine Trouble in General

3. Low output, hesitation and
poor acceleration

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Intake system

Loosened or cracked intake duct

A

Loosened or cracked PCV hose

A

Loosened or cracked vacuum hose

B

Defective intake manifold gasket

B

Defective throttle body gasket

B

Defective PCV valve

B

Loosened oil filler cap

B

Dirty air cleaner element

A

Fuel line

Defective fuel pump and relay

B

Clogged fuel line

B

Lack of or insufficient fuel

C

Belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

B

Loosened cylinder head bolt or defective gasket

B

Improper valve sealing

B

Defective valve stem

C

Worn or broken valve spring

B

Worn or stuck piston rings, cylinder and piston

C

Incorrect valve timing

A

Improper engine oil (low viscosity)

B

Lubrication system

Incorrect oil pressure

B

Cooling system

Overheating

C

Over-cooling

C

Other

Evaporative emission control system malfunction

A

4. Surging

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Intake system

Loosened or cracked intake duct

A

Loosened or cracked PCV hose

A

Loosened or cracked vacuum hose

A

Defective intake manifold gasket

B

Defective throttle body gasket

B

Defective PCV valve

B

Loosened oil filler cap

B

Dirty air cleaner element

B

Fuel line

Defective fuel pump and relay

B

Clogged fuel line

B

Lack of or insufficient fuel

C

Belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective gasket

C

Improper valve sealing

C

Defective valve stem

C

Worn or broken valve spring

C

Worn or stuck piston rings, cylinder and piston

C

Incorrect valve timing

A

Improper engine oil (low viscosity)

B

Cooling system

Overheating

B

Other

Evaporative emission control system malfunction

C

Symptom

Problem parts, etc.

Possible cause

Rank

ME(H4DOTC)-97

MECHANICAL

Engine Trouble in General

5. Engine does not return to
idle.

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Intake system

Loosened or cracked vacuum hose

A

Other

Stuck or damaged throttle valve

A

6. Dieseling (Run-on)

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Cooling system

Overheating

B

Other

Evaporative emission control system malfunction

B

7. After burning in exhaust
system

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Intake system

Loosened or cracked intake duct

C

Loosened or cracked PCV hose

C

Loosened or cracked vacuum hose

B

Defective PCV valve

B

Loosened oil filler cap

C

Belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective gasket

C

Improper valve sealing

B

Defective valve stem

C

Worn or broken valve spring

C

Worn or stuck piston rings, cylinder and piston

C

Incorrect valve timing

A

Lubrication system

Incorrect oil pressure

C

Cooling system

Over-cooling

C

Other

Evaporative emission control system malfunction

C

8. Knocking

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Intake system

Loosened oil filler cap

B

Belt

Defective timing

B

Compression

Incorrect valve clearance

C

Incorrect valve timing

B

Cooling system

Overheating

A

9. Excessive engine oil con-
sumption

Intake system

Loosened or cracked PCV hose

A

Defective PCV valve

B

Loosened oil filler cap

C

Compression

Defective valve stem

A

Worn or stuck piston rings, cylinder and piston

A

Lubrication system

Loosened oil pump attaching bolts and defective gas-
ket

B

Defective oil filter o-ring

B

Defective crankshaft oil seal

B

Defective rocker cover gasket

B

Loosened oil drain plug or defective gasket

B

Loosened oil pan fitting bolts or defective oil pan

B

Symptom

Problem parts, etc.

Possible cause

Rank

ME(H4DOTC)-98

MECHANICAL

Engine Trouble in General

10. Excessive fuel consump-
tion

Engine control system <Ref. to EN(H4DOTC)(diag)-2, Basic Diagnostic Procedure.>

A

Intake system

Dirty air cleaner element

A

Belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective gasket

C

Improper valve sealing

B

Defective valve stem

C

Worn or broken valve spring

C

Worn or stuck piston rings, cylinder and piston

B

Incorrect valve timing

B

Lubrication system

Incorrect oil pressure

C

Cooling system

Over-cooling

C

Symptom

Problem parts, etc.

Possible cause

Rank