Engine malfunctions (Skoda Favorit)

When trying to start the engine, it does not turn over

• The battery terminal connections are loose or oxidized (Section 1).
• The battery is discharged or defective (Section 1 or 12).
• The wiring in the starter circuit is broken, loose or disconnected (Section 12).
• The traction relay or starter switch is faulty (Section 12).
• The starter motor is faulty (Section 12).
• The teeth of the flywheel ring gear or the electric starter pinion are worn or broken (Section 2 or 12).
• The engine ground belt is broken or disconnected (Section 2or 12).

The engine turns over but does not start

• Empty fuel tank.
• The battery is discharged (the engine is turning slowly) (Section 12).
• The battery terminal connections are loose or oxidized (Section 1).
• Ignition components are bypassed or damaged (Section 1 or 5).
• Broken, loose or disconnected wiring in the ignition circuit (Section 1 or 5).
• The spark plugs are worn out or faulty, the interelectrode gap is set incorrectly (Section 1).
• The damper mechanism is jammed, improperly adjusted or faulty (Section 4).
• Mechanical damage (for example, camshaft drive) (Section 2).

A cold engine is difficult to start

• Battery is low (Section 12).
• The battery terminal connections are loose or oxidized (Section 1).
• The spark plugs are worn out or faulty, the interelectrode gap is set incorrectly (Section 1).
• The damper mechanism is jammed, incorrectly adjusted or faulty (Section 4).
• Other malfunction in the ignition system (Section 1 and 5).
• Low compression in the engine cylinder (Section 2).

Warm engine is difficult to start

• The air filter element is dirty or clogged (Section 1).
• The damper mechanism is jammed, improperly adjusted or faulty (Section 4).
• Flooding of the carburetor float chamber (Section 4).
• Low compression in the engine cylinder (Section 2).

The starter is noisy or engages roughly

• The teeth of the flywheel ring gear or the electric starter pinion are worn or broken (Section 2 or 12).
• Starter mounting bolts are loose or missing (Section 12).
• The internal components of the starter are worn or damaged (Section 12).

The engine starts but immediately stalls

• Not enough fuel is getting into the carburetor (Section 4).
• Loose or defective wiring in the ignition circuit (Section 1 or 5).
• Vacuum leak in carburetor or intake manifold (Section 4).
• The jets or internal passages of the carburetor are blocked (Section 4).

The engine runs erratically at idle

• The idle speed and/or mixture is not adjusted correctly (Section 1).
• The air filter element is clogged (Section 1).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).
• The spark plugs are worn out or faulty, the interelectrode gap is set incorrectly (Section 1).
• Valve clearances are not adjusted correctly (Section 1).
• Uneven or low compression in engine cylinders (Section 2).
• The camshaft cams are worn out (Section 2).
• The drive chain is excessively worn (Section 2).

Misfires at idle

• The spark plugs are worn out or faulty, the interelectrode gap is set incorrectly (Section 1).
• Defective high voltage spark plug wiring (Section 1).
• The idle mixture is incorrectly adjusted (Section 1).
• Incorrect ignition timing (Section 1).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).
• The distributor cap is cracked or otherwise damaged (Section 1).
• Valve clearances are not adjusted correctly (Section 1).
• Uneven or low compression in engine cylinders (Section 2).
• The crankcase ventilation hose is disconnected, loosely connected or punctured (Section 1 or 4).

(Article reprinted from the website skodabook.ru)

Misfires in all driving modes

• The jets or internal passages of the carburetor are blocked (Section 4).
• The carburetor is incorrectly adjusted or worn out (Section 1 or 4).
• The fuel filter is blocked (Section 1).
• The fuel pump is faulty or the supply pressure is low (Section 4).
• The drain hole in the fuel tank is blocked or the cross-section of the fuel lines has become smaller (Section 4).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).
• The spark plugs are worn out or faulty, the interelectrode gap is set incorrectly (Section 1).
• The high-voltage spark plug wiring is damaged (Section 1).
• The distributor cap is cracked or otherwise damaged (Section 1).
• Defective ignition coil (Section 5).
• Uneven or low compression in engine cylinders (Section 2).

Engine stalls when accelerator pedal is pressed

• The spark plugs are worn out or faulty, the interelectrode gap is set incorrectly (Section 1).
• The carburetor accelerator pump is faulty (Section 4).
• The jets or internal passages of the carburetor are blocked (Section 4).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).
• The carburetor is incorrectly adjusted or worn out (Section 1 or 4).

The engine stalls

• The idle speed and/or mixture is not adjusted correctly (Section 1).
• The jets or internal passages of the carburetor are blocked (Section 4).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).
• The fuel filter is blocked (Section 1).
• The fuel pump is faulty or the supply pressure is low (Section 4).
• The drain hole in the fuel tank is blocked or the cross-section of the fuel lines has become smaller (Section 4).

The engine does not develop full power

• Incorrect ignition timing (Section 1).
• The carburetor is incorrectly adjusted or worn out (Section 1 or 4)
• The drive chain is not installed correctly (Section 2).
• The fuel filter is blocked (Section 1).
• The fuel pump is faulty or the supply pressure is low (Section 4).
• Uneven or low compression in engine cylinders (Section 2).
• The spark plugs are worn out or faulty, the interelectrode gap is set incorrectly (Section 1).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).
• Wheel braking (Section 1 or 9).
• Clutch slippage (Section 6).

Engine backfires

• Incorrect setting of ignition timing (Section 1).
• The drive chain is not installed correctly (Section 2).
• The carburetor is incorrectly adjusted or worn out (Section 1 or 4).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).

Oil pressure warning light comes on when engine is running

• Low oil level or wrong grade (Section 1).
• Defective oil pressure sensor (Section 2).
• The crankshaft bearings and/or oil pump are worn out (Section 2).
• High engine operating temperature (Section 3).
• The oil pump bypass valve is faulty (Section 2).
• The mesh filter of the oil pump inlet pipe is clogged (Section 2).

The engine runs after the ignition is turned off

• Excessively high idle speed (Section 1).
• Excessive carbon deposits in the engine (Section 2).
• High engine operating temperature (Section 3).

Engine noises

Pre-ignition, detonation on acceleration or under load

• Incorrect setting of ignition timing (Section 1).
• Wrong fuel grade (Section 4).
• Vacuum leak in carburetor, intake manifold or associated hoses (Section 4).
• Excessive carbon deposits in the engine (Section 2).
• The distributor or other ignition system component is worn or damaged (Section 1 or 5).
• The carburetor is incorrectly adjusted or worn out (Section 1 or 4).

Whistling and hissing sounds can be heard

• Leak from the intake manifold or through the carburetor gasket (Section 4).
• Leak through the exhaust manifold gasket or at the joints of the pipe with the manifold (Section 1 or 4).
• Vacuum hose leak (Section 4 or 9).
• The cylinder head gasket has blown (Section 2).

A knocking or rattling sound is heard

• Incorrect valve clearances (Section 1).
• The valve mechanism or camshaft is worn out (Section 2)
• The drive chain is worn out (Section 2).
• Auxiliary components are damaged (cooling system pump, generator, etc.) (Section 3 or 12).

Muffled knock

• Connecting rod bearings are worn out (loud rumble, may weaken under load) (Section 2).
• The main bearings are worn out (rattling or knocking noise, may increase under load) (Section 2).
• Piston knock (more noticeable when the engine is not warmed up) (Section 2).
• Auxiliary components are damaged (generator, cooling system pump, etc.) (Section 3 or 12).