Troubleshooting engine problems (Mazda Capella GC)

The engine won't start

• Battery connections are loose or corroded (Section 5)
• The battery is discharged or faulty (Section 5)
• The wiring in the starter circuit is faulty, loose or open (Section 5)
• The traction relay or starter switch is faulty (Section 5)
• Starter faulty (Section 5)
• The starter pinion and flywheel ring gear teeth are loose or broken (Sections 2 and 5)
• The engine ground is damaged or disconnected (Section 5)

The engine turns over but does not start

• The fuel tank is empty
• The battery is dead (the engine rotates slowly) (Section 5)
• Battery connections are loose or corroded (Section 5)
• Wet or damaged ignition system components (Sections 1 and 5)
• The wiring in the ignition circuit is faulty, loose or open (Sections 1 and 5)
• Spark plugs are worn, faulty, or installed with the incorrect gap (Section 1)
• The choke mechanism is incorrectly adjusted, worn out or sticking (Section 4)
• Major mechanical failure (for example, the camshaft drive) (Section 2)

The engine is difficult to start from a cold state

• The battery is discharged (Section 5)
• Battery connections are loose or corroded (Section 5)
• Spark plugs are worn, faulty, or installed with the incorrect gap (Section 1)
• The choke mechanism is incorrectly adjusted, worn out or sticking (Section 4)
• Other damage to the ignition system (Sections 1 and 5)
• Low compression in engine cylinders (Section 1)

The engine is difficult to start when it is hot

• The air filter element is dirty or clogged (Section 1)
• The choke mechanism is incorrectly adjusted, worn out or sticking (Section 4)
• The carburetor float chamber is full (Section 4)
• Low compression in engine cylinders (Section 1)

The starter is noisy

• The starter pinion and flywheel ring gear teeth are loose or broken (Sections 2 and 5)
• Starter mounting bolts are loose or missing (Section 5)
• The internal components of the starter are worn or damaged (Section 5)

The engine starts but immediately stalls

• Not enough fuel is getting into the carburetor (Section 4)
• The ignition circuit connectors are loose or faulty (Sections 1 and 5)
• Vacuum leak in the carburetor body or intake manifold (Section 4)
• The jets or internal channels of the carburetor are clogged (Section 4)

Unstable operation in idle mode

• The idle speed and/or mixture ratio is incorrectly adjusted (Section 1)
• The air filter element is clogged (Section 1)
• Vacuum leak in the carburetor body, intake manifold or associated hoses (Section 4)
• Spark plugs are worn, faulty, or installed with the incorrect gap (Section 1)
• Uneven or low compression in engine cylinders (Section 1)
• The camshaft cams are worn out (Section 2)
• The drive belt is not tensioned correctly (Section 2)

Misfiring in idle mode

• Spark plugs are worn, faulty, or installed with the incorrect gap (Section 1)
• The high-voltage spark plug wiring is faulty (Section 1)
• The idle mixture is not adjusted correctly (Section 1)
• The ignition timing is incorrectly adjusted (Section 1)
• Vacuum leak in the carburetor body, intake manifold or associated hoses (Section 4)
• The distributor cap is cracked (Section 5)
• Uneven or low compression in engine cylinders (Section 1)
• The crankcase ventilation hoses are disconnected or damaged (Sections 1 and 4)

Misfires across the entire speed range

• The jets or internal channels of the carburetor are clogged (Section 4)
• The carburetor is worn out or improperly adjusted (Sections 1 and 4)
• The fuel filter is clogged (Section 1)
• The fuel pump is faulty or the supply pressure is low (Section 4)
• The fuel tank opening or fuel lines are clogged (Section 4)
• Vacuum leak in the carburetor body, intake manifold or associated hoses (Section 4)
• Spark plugs are worn, faulty, or installed with the incorrect gap (Section 1)
• The high-voltage spark plug wires are faulty (Section 1)
• The distributor cap is cracked (Section 1).
• The ignition coil is faulty (Section 5)
• Uneven or low compression in engine cylinders (Section 1)

The engine accelerates with a delay

• Spark plugs are worn, faulty, or installed with the incorrect gap (Section 1)
• The carburetor accelerator pump is faulty (Section 4)
• The jets or internal channels of the carburetor are clogged (Section 4)
• Vacuum leak in the carburetor body, intake manifold or associated hoses (Section 4)
• The carburetor is worn out or improperly adjusted (Sections 1 and 4)

The engine stalls

• The idle speed and/or mixture ratio are not adjusted correctly (Section 1)
• The jets or internal channels of the carburetor are clogged (Section 4)
• Vacuum leak in the carburetor body, intake manifold or associated hoses (Section 4)
• The fuel filter is clogged (Section 1)
• The fuel pump is faulty or the supply pressure is low (Section 4)
• The fuel tank opening or fuel lines are clogged (Section 4)

Insufficient engine power

• The ignition timing is incorrectly adjusted (Section 1)
• The carburetor is worn out or improperly adjusted (Section 1)
• The drive belt is installed or tensioned incorrectly (Section 2)
• The fuel filter is clogged (Section 1)
• The fuel pump is faulty or the supply pressure is low (Section 4)
• Uneven or low compression in engine cylinders (Section 1)
• Spark plugs are worn, faulty, or installed with the incorrect gap (Section 1)
• Vacuum leak in the carburetor body, intake manifold or associated hoses (Section 4)
• Wheel braking (Sections 1 and 9)
• Clutch slippage (Section 8)

The oil pressure warning light comes on when the engine is running

• Low oil level or incorrect oil type added (Section 1)
• The oil pressure sensor is faulty (Section 12)
• The engine bearings and/or oil pump are worn out (Section 2)
• High engine operating temperature (Section 3)
• The oil pressure reducing valve is faulty (Section 2)
• The mesh filter of the oil pump inlet pipe is clogged (Section 2)

The engine continues to run after being turned off

• Idle speed too high (Section 1)
• The fuel shut-off valve is faulty (Section 4)
• Excessive carbon deposits in the engine (Section 2)
• High engine operating temperature (Section 3)

Engine noises

Detonation or knocking during acceleration or when the vehicle is loaded

• Incorrect ignition timing (Section 1)
• The wrong type of fuel was filled (Section 4)
• Vacuum leak in the carburetor body, intake manifold or associated hoses (Section 4)
• Excessive carbon deposits in the engine (Section 2)
• The distributor or other components of the ignition system are worn or damaged (Section 5)
• The carburetor is worn out or improperly adjusted (Section 1)

Whistling or wheezing sounds

• The intake manifold or carburetor gasket is leaking (Section 4)
• The exhaust manifold gasket or the connection between the exhaust pipe and the manifold is leaking (Section 1)
• Vacuum hose leaking air (Sections 4 and 9)
• The cylinder head gasket has blown (Section 2)

A slight tapping or rattling sound

• Hydraulic tappets are faulty (Section 2)
• Worn valve train or camshaft (Section 2)
• The timing belt or its tensioning mechanism is worn out (Section 2)
• Auxiliary components are damaged (water pump, generator, etc) (Sections 3 and 5)

Loud or dull knocking sound

• The connecting rod bearings are worn out (a regular loud knocking sound, possibly decreasing when the vehicle is loaded) (Section 2)
• The main bearings are worn out (a loud knocking sound, possibly increasing when the vehicle is loaded) (Section 2)
• The piston is damaged (most noticeable when the engine is not warmed up) (Section 2)
• Auxiliary components are damaged (water pump, generator, etc) (Sections 3 and 5)