Mercedes W124

since 1985-1995 of release

Repair and car operation



W124 Mercedes
+ Governing bodies and control devices
+ MAINTENANCE
+ 2. Maintenance (diesel engines)
+ ENGINE
+ 4. Repair of 6-cylinder petrol SOHC engines
+ 5. Repair of 6-cylinder petrol DOHC engines
+ 6. Repair of the diesel engine established in the car
+ 7. Major maintenance of engines
+ COOLING SYSTEM
+ FUEL SYSTEM
+ 10. System of injection of BOSCH CIS-E fuel (KE-JETRONIC)
+ 11. System of injection of BOSCH HFM fuel
+ 12. Fuel system of diesel engines
+ 13. Fuel system of diesel engines
+ SYSTEMS OF START, IGNITION
+ 15. System of ignition of 4-cylinder petrol engines
+ 16. System of ignition of four-cylinder petrol engines
+ PRESTARTING HEATING
+ TRANSMISSION
+ 19. Mechanical transmission
+ 20. Automatic transmission
+ POWER SHAFTS
+ BRAKE SYSTEM
+ SUSPENSION BRACKET
+ BODY
+ ELECTRIC EQUIPMENT
- CHECK OF MALFUNCTIONS
   26.2. Cooling system
   26.3. Fuel and exhaust systems
   26.4. Coupling
   26.5. Mechanical transmission
   26.6. Automatic transmission
   26.7. Differential and driveshaft
   26.8. Brake system
   26.9. Suspension bracket and steering
   26.10. Electric equipment



8-499-391-38-82 .



CHECK OF MALFUNCTIONS

26. Determination of malfunctions

26.1. Engine

GENERAL INFORMATION

The cranked shaft of the engine does not rotate or rotates very slowly at engine start by a starter

• Unreliable connections of plugs of the accumulator.
• The accumulator is discharged or faulty.
• Electroconducting in a starter power-supply circuit is unreliably connected or faulty.
• The traction relay or contacts of the switch of a starter is faulty.
• Starter damage.
• There is no gearing of a gear wheel of a starter to a gear wreath of a flywheel.
• The tire of grounding of the engine is damaged or unreliably connected.

The cranked shaft of the engine rotates, but the engine is not started

• There is no fuel.
• The accumulator is discharged. Thus the cranked shaft of the engine rotates very slowly.
• Accumulator plugs are unreliably connected.
• On models with petrol engines elements of system of ignition are damaged or on them there are pairs of moisture.
• On models with petrol engines electroconducting in ignition system is faulty.
• On models with petrol engines spark plugs are faulty or the interelectrode gap of a candle is not adjusted.
• On models with diesel engines the system of prestarting heating is faulty.
• On models with petrol engines with the carburetor the mechanism of a zaslonka is faulty or incorrectly adjusted or the zaslonka of the valve of an otsechka of fuel is faulty.
• On models with diesel engines the valve of a stop of the engine is faulty.
• On models with diesel engines there is an air at fuel system.
• Serious mechanical defect of the engine.

The complicated start of the cold engine

• The accumulator is discharged.
• Unreliable connection or oxidation of plugs of the accumulator.
• On models with petrol engines spark plugs are faulty or the interelectrode gap of a candle is not adjusted.
• On models with diesel engines the system of prestarting heating is faulty.
• On models with petrol engines with the carburetor the mechanism of a zaslonka is faulty or incorrectly adjusted or the zaslonka of the valve of an otsechka of fuel is faulty.
• On models with petrol engines the system of injection of fuel is faulty.
• On models with petrol engines electroconducting in ignition system is faulty.
• On models with diesel engines the valve of the raised turns of idling is incorrectly adjusted.
• A low compression in engine cylinders.

The complicated start of the hot engine

• The filtering element of the air filter is polluted.
• On models with petrol engines with the carburetor the mechanism of a zaslonka is faulty or incorrectly adjusted or the zaslonka of the valve of an otsechka of fuel is faulty.
• On models with petrol engines the system of injection of fuel is faulty.
• A low compression in engine cylinders.

Strong noise at starter work

• Teeths of a gear wheel of a starter or a gear wreath of a flywheel are worn-out or broken.
• Bolts of fastening of a starter are weakened or are absent.
• Internal details of a starter are worn-out or damaged.

The engine is started, but at once stops

• On models with petrol engines contacts in electric sockets are faulty or weakened.
• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.

Unstable operation of the engine on idling turns

• The filtering element of the air filter is polluted.
• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• On models with petrol engines spark plugs are faulty or the interelectrode gap of a candle is not adjusted.
• A low compression in engine cylinders.
• Camshaft cams are worn-out.
• The driving chain is incorrectly established.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.
• On models with diesel engines fuel nozzles are faulty.

Ignition admissions on idling turns

• On models with petrol engines spark plugs are faulty or the interelectrode gap of a candle is not adjusted.
• On models with petrol engines high-voltage wires are faulty.
• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.
• On models with diesel engines fuel nozzles are faulty.
• On models with petrol engines there are cracks on a cover of the distributor of ignition.
• A non-uniform or low compression in engine cylinders.
• Hoses of ventilation of a case are unreliably connected or damaged.

Ignition admissions on all turns of the engine

• Pollution of the fuel filter.
• The fuel pump is faulty or submits fuel under low pressure.
• Pollution of a fuel tank or fuel tubes.
• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• On models with petrol engines spark plugs are faulty or the interelectrode gap of a candle is not adjusted.
• On models with petrol engines high-voltage wires are faulty.
• On models with diesel engines fuel nozzles are faulty.
• On models with petrol engines the ignition coil is faulty.
• On models with petrol engines there are cracks on a cover of the distributor of ignition.
• A non-uniform or low compression in engine cylinders.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.

Acceleration of the engine occurs to a delay

• On models with petrol engines spark plugs are faulty or the interelectrode gap of a candle is not adjusted.
• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.
• On models with diesel engines fuel nozzles are faulty.

The engine stops

• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• Pollution of the fuel filter.
• The fuel pump is faulty or submits fuel under low pressure.
• Pollution of a fuel tank or fuel tubes.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.
• On models with diesel engines fuel nozzles are faulty.

Engine capacity reduction

• The driving chain is incorrectly established.
• Pollution of the fuel filter.
• The fuel pump is faulty or submits fuel under low pressure.
• On models with petrol engines spark plugs are faulty or the interelectrode gap of a candle is not adjusted.
• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.
• On models with diesel engines fuel nozzles are faulty.
• On models with diesel engines the moment of injection of fuel is incorrectly adjusted.
• Pritormazhivaniye of wheels at car movement.
• Incomplete inclusion of coupling (coupling slips).

Fire of a control lamp of pressure of oil at the working engine

• Low level of oil in the engine or oil of not demanded type is filled in.
• The sensor of pressure of oil is faulty.
• Radical bearings of a cranked shaft and/or the oil pump are worn-out.
• Engine overheat.
• The safety valve of the oil pump is faulty.
• Pollution of the mesh filter of a maslopriyemny tube of the oil pump.

The engine continues to work after its switching off

• A thick layer of a deposit in combustion chambers.
• Engine overheat.
• On models with petrol engines with the carburetor the winding of the electromagnetic valve of an otsechka of fuel is faulty.
• On models with petrol engines with system of injection of fuel damage to system of injection of fuel.
• On models with diesel engines the electromagnetic valve of a stop of the engine is faulty.

Extraneous noise in the engine

Detonation or knocks at acceleration or at a full load of the car

• On models with petrol engines the corner of an advancing of ignition is incorrectly adjusted.
• On models with petrol engines spark plugs not that type are established.
• Fuel with low octane number is used.
• On models with petrol engines additional подсос air in the case of the carburetor or an inlet collector.
• A thick layer of a deposit in combustion chambers.
• On models with petrol engines with the carburetor jets or internal channels of the carburetor are hammered.
• On models with petrol engines with system of injection of fuel the system of injection of fuel or an injector is damaged or hammered.

Whistling or rattling noise

• On models with petrol engines laying of an inlet collector or the carburetor/throttle case is not tight.
• Laying of a final collector or connection of a final collector with a reception exhaust pipe is not tight.
• Damage of a vacuum hose of the vacuum amplifier of brakes.
• Burn-out of laying of a head of the block of cylinders.

Insignificant knock or jingle

• Wear of the mechanism of a drive of valves or camshaft.
• Wear or damage of auxiliary units of the engine (water pump, generator etc.).

Loud or deaf knock

• Shatunny bearings of a cranked shaft (the continuous strong knock decreasing at increase in loading) are worn-out.
• Radical bearings of a cranked shaft (the strong knock increasing at increase in loading) are worn-out.
• Piston damage (it is especially notable at operation of the cold engine).