1. Engine does not start.

1) Starter does not turn.

Starter

Defective battery-to-starter harness

B

Defective starter switch

C

Defective inhibitor switch or neutral switch

C

Defective starter

B

Battery

Improper connection of terminal

A

Run-down battery

A

Defective charging system

B

Excessive friction

Seizure of crankshaft and connecting rod bearing

C

Seized camshaft

C

Seized or stuck piston and cylinder

C

2) Initial combustion does not occur.

Starter

Defective starter

C

Engine control system

A

Fuel line

Defective fuel pump and relay

A

Clogged fuel line

C

Lack of or insufficient fuel

B

Timing belt

Degradation, etc.

B

Defective timing

B

Compression

Incorrect valve clearance

C

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective head gasket

C

Improper valve sealing

C

Defective valve stem

C

Worn or broken valve spring

B

Worn or stuck piston rings, cylinder and piston

C

Incorrect valve timing

B

Improper engine oil (low viscosity)

B

3) Initial combustion occurs.

Engine control system

A

Intake system

Defective intake manifold gasket

B

Defective throttle body gasket

B

Fuel line

Defective fuel pump and relay

C

Clogged fuel line

C

Lack of or insufficient fuel

B

Timing belt

Degradation, etc.

B

Defective timing

B

Compression

Incorrect valve clearance

C

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective head gasket

C

Improper valve sealing

C

Defective valve stem

C

Worn or broken valve spring

B

Worn or stuck piston rings, cylinder and piston

C

Incorrect valve timing

B

Improper engine oil (low viscosity)

B

4) Engine stalls after initial combustion.

Engine control system

A

Intake system

Loosened or cracked intake duct

B

Loosened or cracked PCV hose

C

Loosened or cracked vacuum hose

C

Defective intake manifold gasket

B

Defective throttle body gasket

B

Dirty air cleaner element

C

Fuel line

Clogged fuel line

C

Lack of or insufficient fuel

B

Timing belt

Degradation, etc.

B

Defective timing

B

Compression

Incorrect valve clearance

C

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective head gasket

C

Improper valve sealing

C

Defective valve stem

C

Worn or broken valve spring

B

Worn or stuck piston rings, cylinder and piston

C

Incorrect valve timing

B

Improper engine oil (low viscosity)

B

2. Rough idle and engine stall

Engine control system

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

Timing belt

Defective timing

C

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

B

Loosened cylinder head bolt or defective head 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

Others

Evaporative emission control system malfunction

A

Stuck or damaged throttle valve

B

Accelerator cable out of adjustment

C

3. Low output, hesitation and poor acceleration

Engine control system

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

Timing belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

B

Loosened cylinder head bolt or defective head 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

Others

Evaporative emission control system malfunction

A

4. Surging

Engine control system

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

Timing belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective head 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

Others

Evaporative emission control system malfunction

C

5. Engine does not return to idle.

Engine control system

A

Intake system

Loosened or cracked vacuum hose

A

Others

Stuck or damaged throttle valve

A

Accelerator cable out of adjustment

B

6. Dieseling (Run-on)

Engine control system

A

Cooling system

Overheating

B

Others

Evaporative emission control system malfunction

B

7. After burning in exhaust system

Engine control system

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

Timing belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective head 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

Others

Evaporative emission control system malfunction

C

8. Knocking

Engine control system

A

Intake system

Loosened oil filler cap

B

Timing belt

Defective timing

B

Compression

Incorrect valve clearance

C

Incorrect valve timing

B

Cooling system

Overheating

A

9. Excessive engine oil consumption

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 gasket

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

10. Excessive fuel consumption

Engine control system

A

Intake system

Dirty air cleaner element

A

Timing belt

Defective timing

B

Compression

Incorrect valve clearance

B

Loosened spark plug or defective gasket

C

Loosened cylinder head bolt or defective head 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