| Condition | Possible Cause | Action |
|---|---|---|
|
Hard starting (Engine cranks OK)
|
Faulty spark plug
|
|
|
Leaky high-tension cord
|
||
|
Loose connection or disconnection of high tension cords or lead wires
|
||
|
Faulty ignition coil
|
||
|
Dirty or clogged fuel hose or pipe
|
||
|
Malfunctioning fuel pump
|
||
|
Air inhaling from intake manifold gasket or throttle body gasket
|
||
|
Faulty idle air control system
|
||
|
Faulty ECT sensor or MAF sensor
|
||
|
Faulty ECM
|
||
|
Low compression
|
||
|
Poor spark plug tightening or faulty gasket
|
||
|
Compression leak from valve seat
|
||
|
Sticky valve stem
|
||
|
Weak or damaged valve springs
|
||
|
Compression leak at cylinder head gasket
|
||
|
Sticking or damaged piston ring
|
||
|
Worn piston, ring or cylinder
|
||
|
Malfunctioning PCV valve
|
||
|
Camshaft position control (VVT) system out of order
|
||
|
Faulty EGR system
|
||
|
Engine has no power
|
Faulty spark plug
|
|
|
Faulty ignition coil with ignitor
|
||
|
Leaks, loose connection or disconnection of high-tension cord
|
||
|
Faulty knock sensor
|
||
|
Clogged fuel hose or pipe
|
||
|
Malfunctioning fuel pump
|
||
|
Air inhaling from intake manifold gasket or throttle body gasket
|
||
|
Engine overheating
|
“Overheating” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Malfunctioning EGR valve
|
||
|
Maladjusted accelerator cable play
|
||
|
Poor performance of TP sensor, ECT sensor or MAF sensor
|
||
|
Faulty fuel injector(s)
|
||
|
Faulty ECM
|
||
|
Dragging brakes
|
||
|
Slipping clutch
|
||
|
Low compression
|
||
|
Camshaft position control (VVT) system out of order
|
||
|
Improper engine idling or engine fails to idle
|
Faulty spark plug
|
|
|
Leaky or disconnected high-tension cord
|
||
|
Faulty ignition coil with ignitor
|
||
|
Fuel pressure out of specification
|
||
|
Leaky manifold, throttle body, or cylinder head gasket
|
||
|
Malfunctioning EGR valve
|
||
|
Faulty idle air control system
|
||
|
Faulty evaporative emission control system
|
||
|
Faulty EGR system
|
||
|
Faulty fuel injector(s)
|
||
|
Poor performance of ECT sensor, TP sensor or MAF sensor
|
||
|
Faulty ECM
|
||
|
Loose connection or disconnection of vacuum hoses
|
||
|
Malfunctioning PCV valve
|
||
|
Engine overheating
|
“Overheating” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Low compression
|
||
|
Camshaft position control (VVT) system out of order
|
||
|
Engine hesitates (Momentary lack of response as the accelerator is depressed. Can occur at all vehicle speeds. Usually most severe when first trying to make the vehicle move, as from a stop sign.)
|
Spark plug faulty or plug gap out of adjustment
|
|
|
Leaky high-tension cord
|
||
|
Fuel pressure out of specification
|
||
|
Malfunctioning EGR valve
|
||
|
Poor performance of TP sensor, ECT sensor or MAF sensor
|
||
|
Faulty fuel injector
|
||
|
Faulty ECM
|
||
|
Engine overheating
|
“Overheating” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Low compression
|
“Low Compression” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Camshaft position control (VVT) system out order
|
||
|
Surges (Engine power variation under steady throttle or cruise. Feels like the vehicle speeds up and down with no change in the accelerator pedal.)
|
Leaky or loosely connected high-tension cord
|
|
|
Faulty spark plug (excess carbon deposits, improper gap, burned electrodes, etc.)
|
||
|
Variable fuel pressure
|
||
|
Kinky or damaged fuel hose and lines
|
||
|
Faulty fuel pump (clogged fuel filter)
|
||
|
Malfunctioning EGR valve
|
||
|
Poor performance of MAF sensor
|
||
|
Faulty fuel injector
|
||
|
Faulty ECM
|
||
|
Excessive detonation (The engine makes continuously sharp metallic knocks that change with throttle opening. Sounds like pop corn popping.)
|
Faulty spark plug
|
|
|
Loose connection of high-tension cord
|
||
|
Engine overheating
|
“Overheating” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Clogged fuel filter (faulty fuel pump) or fuel lines
|
||
|
Air inhaling from intake manifold or throttle body gasket
|
||
|
Malfunctioning EGR valve
|
||
|
Poor performance of knock sensor, ECT sensor or MAF sensor
|
||
|
Faulty fuel injector(s)
|
||
|
Faulty ECM
|
||
|
Excessive combustion chamber deposits
|
||
|
Camshaft position control (VVT) system out of order
|
||
|
Overheating
|
Inoperative thermostat
|
|
|
Poor water pump performance
|
||
|
Clogged or leaky radiator
|
||
|
Improper engine oil grade
|
||
|
Clogged oil filter or oil strainer
|
||
|
Poor oil pump performance
|
||
|
Faulty A/C condenser fan control system
|
||
|
Faulty radiator cooling fan clutch
|
||
|
Dragging brakes
|
||
|
Slipping clutch
|
||
|
Blown cylinder head gasket
|
||
|
Poor gasoline mileage
|
Leaks or loose connection of high-tension cord
|
|
|
Faulty spark plug (improper gap, heavy deposits and burned electrodes, etc.)
|
||
|
Malfunctioning EGR valve
|
||
|
High idle speed
|
“Improper Engine Idling or Engine Fails to Idle” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Poor performance of TP sensor, ECT sensor or MAF sensor
|
||
|
Faulty fuel injector(s)
|
||
|
Faulty ECM
|
||
|
Low Compression
|
“Low Compression” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Poor valve seating
|
||
|
Dragging brakes
|
||
|
Slipping clutch
|
||
|
Thermostat out of order
|
||
|
Improper tire pressure
|
“Replacement Tires” under
Tires Description
|
|
|
Camshaft position control (VVT) system out of order
|
||
|
Excessive engine oil consumption – Oil leakage
|
Blown cylinder head gasket
|
|
|
Leaky camshaft oil seals
|
||
|
Sticky piston ring
|
||
|
Worn piston and cylinder
|
||
|
Worn piston ring groove and ring
|
||
|
Improper location of piston ring gap
|
||
|
Worn or damaged valve stem seal
|
||
|
Worn valve stem
|
||
|
Low oil pressure
|
Improper oil viscosity
|
|
|
Malfunctioning oil pressure switch
|
||
|
Clogged oil strainer
|
||
|
Functional deterioration of oil pump
|
||
|
Worn oil pump relief valve
|
||
|
Excessive clearance in various sliding parts
|
||
|
Engine noise – Valve noise
NOTE:
Before checking mechanical noise, make sure that: Specified spark plug is used. Specified fuel is used.
|
Improper valve lash
|
|
|
Worn valve stem and guide
|
||
|
Weak or broken valve spring
|
||
|
Warped or bent valve
|
||
|
Engine noise – Piston, ring and cylinder noise
NOTE:
Before checking mechanical noise, make sure that: Specified spark plug is used. Specified fuel is used.
|
Worn piston, ring cylinder bore
|
|
|
Engine noise – Connecting rod noise
NOTE:
Before checking mechanical noise, make sure that: Specified spark plug is used. Specified fuel is used.
|
Worn piston, ring cylinder bore
|
|
|
Worn rod bearing
|
||
|
Worn crank pin
|
||
|
Loose connecting rod nuts
|
||
|
Low oil pressure
|
“Low Oil Pressure” under
Engine Symptom Diagnosis:M13A with VVT
|
|
|
Engine noise – Crankshaft noise
NOTE:
Before checking mechanical noise, make sure that: Specified spark plug is used. Specified fuel is used.
|
Low oil pressure
|
“Low Oil Pressure” under
Engine Symptom Diagnosis:M13A with VVT
|
|
Worn bearing
|
||
|
Worn crankshaft journal
|
||
|
Loose bearing cap bolts
|
||
|
Excessive crankshaft thrust play
|
||
|
Excessive hydrocarbon (HC) emission or carbon monoxide (CO)
|
Faulty spark plug
|
|
|
Leaky or disconnected high-tension cord
|
||
|
Faulty ignition coil with ignitor
|
||
|
Low compression
|
||
|
Lead contamination of three way catalytic converter
|
Check for absence of filler neck restrictor
|
|
|
Faulty evaporative emission control system
|
||
|
Fuel pressure out of specification
|
||
|
Closed loop system (A/F feed back compensation) fails
– Faulty TP sensor
– Poor performance of ECT sensor or MAF sensor
|
||
|
Faulty injector(s)
|
||
|
Faulty ECM
|
||
|
Engine not at normal operating temperature
|
||
|
Clogged air cleaner
|
||
|
Vacuum leaks
|
||
|
Camshaft position control (VVT) system out of order
|
||
|
Excessive nitrogen oxides (NOx) emission
|
Improper ignition timing
|
|
|
Lead contamination of catalytic converter
|
Check for absence of filler neck restrictor
|
|
|
Faulty EGR system
|
||
|
Fuel pressure out of specification
|
||
|
Closed loop system (A/F feed back compensation) fails
– Faulty TP sensor
– Poor performance of ECT sensor or MAF sensor
|
||
|
Faulty injector(s)
|
||
|
Faulty ECM
|
||
|
Camshaft position control (VVT) system out of order
|