The engine crankshaft does not rotate or rotates very slowly when the engine is started by the starter
- Insecure battery terminal connections.
- Discharged or defective battery.
- Loose or faulty wiring in the starter power circuit.
- Faulty traction relay or starter switch contacts.
- Starter damage.
- The starter gear does not mesh with the flywheel ring gear.
- Motor ground bus broken or loose.
The engine crankshaft rotates, but the engine does not start
- There is no fuel.
- Discharged battery. In this case, the crankshaft of the engine rotates very slowly.
- Battery terminals not securely connected.
- On models with gasoline engines, elements of the ignition system are damaged or moisture vapor is present on them.
- On models with gasoline engines, the wiring in the ignition system is faulty.
- On models with gasoline engines, the spark plugs are faulty or the spark plug gap is not adjusted.
- On models with diesel engines, the preheating system is faulty.
- On models with gasoline engines with a carburetor, the throttle mechanism is faulty or incorrectly adjusted, or the throttle of the fuel cut-off valve is faulty.
- On models with diesel engines, the engine stop valve is faulty.
- Diesel models have air in the fuel system.
- Serious mechanical defect in the engine.
Difficulty starting a cold engine
- Discharged battery.
- Unreliable connection or oxidation of battery terminals.
- On models with gasoline engines, the spark plugs are faulty or the spark plug gap is not adjusted.
- On models with diesel engines, the preheating system is faulty.
- On models with gasoline engines with a carburetor, the throttle mechanism is faulty or incorrectly adjusted, or the throttle of the fuel cut-off valve is faulty.
- On models with gasoline engines, the fuel injection system is faulty.
- On models with gasoline engines, the wiring in the ignition system is faulty.
- On diesel models, the high idle valve is incorrectly adjusted.
- Low compression in the engine cylinders.
Difficulty starting a hot engine
- The air filter element is dirty.
- On models with gasoline engines with a carburetor, the throttle mechanism is faulty or incorrectly adjusted, or the throttle of the fuel cut-off valve is faulty.
- On models with gasoline engines, the fuel injection system is faulty.
- Low compression in the engine cylinders.
Loud noise during starter operation
- Worn or broken starter gear teeth or flywheel ring gear.
- Loose or missing starter mounting bolts.
- Worn or damaged starter internals.
Engine starts but stops immediately
- On models with gasoline engines, the contacts in the electrical connectors are faulty or loose.
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
Unstable operation of the engine at idle speed
- The air filter element is dirty.
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- On models with gasoline engines, the spark plugs are faulty or the spark plug gap is not adjusted.
- Low compression in the engine cylinders.
- Worn camshaft lobes.
- Drive chain incorrectly installed.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
- On models with diesel engines, the fuel injectors are faulty.
Ignition misfires at idle
- On models with gasoline engines, the spark plugs are faulty or the spark plug gap is not adjusted.
- On models with gasoline engines, high-voltage wires are faulty.
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
- On models with diesel engines, the fuel injectors are faulty.
- On models with gasoline engines, there are cracks on the ignition distributor cap.
- Uneven or low compression in the engine cylinders.
- Loose or damaged crankcase breather hoses.
Misfiring at all engine speeds
- Fuel filter dirty.
- The fuel pump is faulty or delivers fuel at low pressure.
- Fuel tank or fuel lines dirty.
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- On models with gasoline engines, the spark plugs are faulty or the spark plug gap is not adjusted.
- On models with gasoline engines, high-voltage wires are faulty.
- On models with diesel engines, the fuel injectors are faulty.
- On models with gasoline engines, the ignition coil is faulty.
- On models with gasoline engines, there are cracks on the ignition distributor cap.
- Uneven or low compression in the engine cylinders.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
Engine acceleration is delayed
- On models with gasoline engines, the spark plugs are faulty or the spark plug gap is not adjusted.
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
- On models with diesel engines, the fuel injectors are faulty.
Engine stops
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- Fuel filter dirty.
- The fuel pump is faulty or delivers fuel at low pressure.
- Fuel tank or fuel lines dirty.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
- On models with diesel engines, the fuel injectors are faulty.
Engine power reduction
- Drive chain incorrectly installed.
- Fuel filter dirty.
- The fuel pump is faulty or delivers fuel at low pressure.
- On models with gasoline engines, the spark plugs are faulty or the spark plug gap is not adjusted.
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
- On models with diesel engines, the fuel injectors are faulty.
- On models with diesel engines, the fuel injection timing is incorrectly adjusted.
- Braking of the wheels when the car is moving.
- Incomplete engagement of the clutch (clutch slips).
Ignition of a control lamp of pressure of oil at the working engine
- The engine oil level is low or the wrong type of oil is filled.
- Defective oil pressure sensor.
- Worn crankshaft main bearings and/or oil pump.
- Engine overheating.
- Defective oil pump relief valve.
- Contamination of the mesh filter of the oil pick-up tube of the oil pump.
Engine continues to run after shutdown
- Thick layer of soot in combustion chambers.
- Engine overheating.
- On models with gasoline engines with a carburetor, the winding of the fuel cut-off solenoid valve is faulty.
- On models with gasoline engines with a fuel injection system, damage to the fuel injection system.
- On models with diesel engines, the engine stop solenoid valve is faulty.
Extraneous noises in the engine
Knocking or knocking sound when accelerating or when the vehicle is fully loaded
- On models with gasoline engines, the ignition timing is incorrectly adjusted.
- The wrong type of spark plugs are installed on models with petrol engines.
- Low octane fuel is used.
- On models with gasoline engines, additional air leakage in the carburetor body or intake manifold.
- Thick layer of soot in combustion chambers.
- On models with gasoline engines with a carburetor, the jets or internal channels of the carburetor are clogged.
- On models with gasoline engines with a fuel injection system, the fuel injection system or injector is damaged or clogged.
Whistling or wheezing noises
- On models with gasoline engines, the gasket of the intake manifold or the carburetor / throttle body is leaking.
- Leaky exhaust manifold gasket or connection between exhaust manifold and exhaust pipe.
- Damage to the vacuum hose of the vacuum brake booster.
- Burnt cylinder head gasket.
Minor knocking or rattling
- Deterioration of the valve drive mechanism or camshaft.
- Worn or damaged engine accessories (water pump, generator, etc).
Loud or dull thud
- Worn crankshaft connecting rod bearings (constant strong knocking, decreasing with increasing load).
- Worn crankshaft bearings (loud knocking that increases with increasing load).
- Piston damage (especially noticeable when running a cold engine).