Mercedes of the S-class W202

1993-2000 of release

Repair and operation of the car

Mercedes W202
+ 1.2. General information
+ 2. Maintenance
+ 3. Engines
+ 4. Lubrication system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. System of ignition
- 8. Fuel system
   + 8.1.1. Introduction
   - 8.2. System of injection of petrol engines Principle of work of PMS Principle of work of HFM
      8.2.2. Self-diagnosing of a condition of system of ignition and injection of fuel
      8.2.3. Air flowmeter
      8.2.4. Thermal sensor of cooling liquid
      8.2.5. The sensor of the soaked-up air
      8.2.6. System of vacuum pipelines
      8.2.7. The fuel distributor with valvate nozzles
      8.2.8. Valvate nozzles
      8.2.9. Oxygen sensor (lambda probe)
      8.2.10. Diagnostics of malfunctions of system of injection of gasoline
      8.2.11. What should be known to the owner of the car with the injector engine
      8.2.12. Turbo doctor
   + 8.3. System of injection and power supply of diesel engines
   + 8.4. System of production of exhaust gases
+ 9. Transmission
+ 10. Running gear
+ 11. Steering
+ 12. Brake system
+ 13. Body
+ 14. Electric equipment
+ 14.2. Electrical circuitries

8.2.10. Diagnostics of malfunctions of system of injection of gasoline


Before on the basis of diagnostics of malfunctions the malfunction is found, the following control prerequisites have to be executed: correctly start the engine. Both for cold, and for the heated-up engine fairly following: do not press an accelerator pedal during start, squeeze out a coupling pedal. In a tank there has to be a fuel, in the mechanical relation the engine also has to be as it should be, the rechargeable battery is charged, the starter rotates with a sufficient frequency, system of ignition as it should be, the power supply system is tight and is not polluted, ventilation of a case as it should be, reliable electric connection with the car case is provided (the engine – the transmission – a body). In auto repair shop charge to interview memory of malfunctions.


If fuel-supply lines unscrew, they need to be washed out with use of means for cold cleaning (cleaners) or gasoline in advance.

The engine is not started
At inclusion of a starter the fuel pump with the electric drive is not started (noise during the work is not heard)
Slightly knock on a pump housing that perhaps frozen up pump could separate. Check whether tension on the pump moves. Check electric contacts for good conductivity.
The safety lock is faulty
Check a safety lock of the fuel pump.
The relay of the fuel pump is faulty
Check the relay.
To valvate nozzles tension does not move
Snimimte shtekkerny sockets from nozzles, connect a control bulb and press a starter. The control bulb has to blink poorly. If the bulb gleams: replace the actuation device. If the control bulb does not shine: check the relay of the fuel pump.
The cold engine is badly started, works spasmodically
The thermal sensor is faulty
Check the thermal sensor.
The oxygen sensor is faulty
Charge to check the oxygen sensor, if necessary replace.
The engine stops (works with interruptions)
The electric connections relating to the fuel pump are periodically disconnected
Check for strong and faultless connection shtekkerny connections and connections of electric wires on the fuel pump and its relay. Check a safety lock and places of engagement for the relay of the fuel pump. Clean contacts.
Too low volume supply of fuel pump
Charge to auto repair shop to check volume supply of fuel.
The fuel filter is littered
Replace the fuel filter.
The fuel pump is faulty
Check the fuel pump.
The valvate nozzle is untight
Check a valvate nozzle.
The engine has defects during the work on the transitional modes
The system of an admission of air is untight
Check system of an admission of the engine. For this purpose leave to work the engine in the mode of idling and miss the mark with gasoline of the place of an uplrtneniye, and also connection in the soaking-up highway. If rotation frequency quickly increases, then it is necessary to eliminate the available leakage. Attention: vapors of gasoline are poisonous, do not inhale them!
The thermal sensor of cooling liquid is faulty
Check the thermal sensor.
The power supply system is untight
Examine all junctions in a zone of the engine and electric fuel pump.
The hot engine is not started
Too high pressure in a power supply system
Charge to check pressure in a power supply system, if necessary replace pressure regulator.
The drain line between the regulator of pressure and the fuel pump is littered or bent Clean or replace the line (pipeline).