Fuel system device (Mondeo 3)

With a modern accelerator, the Mondeo has become a rare guest at the petrol pump. Petrol engine variants burn Euro-Super – diesel Mondeos take fuel from the diesel pump.

The fuel tank of the Mondeo is located in the rear area of the floor under the rear seat. It is a low-lying plastic molding. Models with petrol engines have a fuel capacity of approximately 59 liters, both diesel versions load about 56 liters on board. In carburettor engines, a fuel level sensor (fuel reserve indicator) and a fuel pump are located directly in the tank. The 66 kW diesel version pours the "juice" from the tank via a feed pump built into the plunger distributor, in the 85 kW diesel unit this is taken care of by two pumps: the first, as in the 66 kW, sits directly in the fuel pump, the second pump works as an electric feed pump and is located outside under the car's floor. They ensure the supply of diesel fuel and prevent the formation of a low pressure limit of 0.2 bar at the inlet of the fuel pump.

The Mondeo fuel tank does not have a threaded drain plug - so before working on the fuel tanks, its contents must be emptied through the ventilation hole.

Clever - ventilation system

An electric fuel suction compressor (supply pump) in petrol models transports fuel through the fuel line system from the fuel tank to the engine. In order to "bind" impurities and water condensate, a fuel filter is located in the supply line. All Mondeos with petrol engines "carry" the filter under the base of the monocoque body near the right rear wheel, on the contrary, in diesel Mondeos it is located under the engine hood at the height of the right projection of the shock absorber strut. Ventilation and airing mainly ends in the filler neck of the tank. From here, the air that penetrates during filling the tank and in accordance with current fuel consumption is removed. In order not to excessively pollute the environment with toxic fuel vapors, the filter binds the removed fuel vapors with activated carbon and sends them back to the suction tract when the engine is running.




Fuel system of the four-cylinder Mondeo

1 — Fuel distribution pipe, 2 — Pressure damper, 3 - Low pressure pipeline, 4 — Fuel line, 5 — Pressure reducing valve,	6 - Drain pipe, 7 - Submersible fuel pump, 8 — Feed pipe (part of submersible fuel pump), 9 — Fuel filter, 10 — Fuel level sensor.

Main elements of the fuel system

Fuel pump: The Mondeo uses a silent electric submersible fuel pump. The pump and sensor are a single element, unused fuel and gases are returned to the tank through a pressure reducing valve in the pump body.

Two in one: submersible fuel pump in versions with petrol engines.

This valve maintains "petrol pressure" in the injection system even when the ignition is off.

Fuel filter: in petrol and diesel engines it is installed before the injection system. It binds liquid and solid ballast substances from the fuel.



Activated carbon filter: located in the engine compartment. Binds fuel vapors from the tank. When the engine is running, it opens the electromagnetic valve - gases from this filter enter the intake system and mix with the fresh fuel mixture.

Basic connection diagram of the activated carbon filter

1 - Fuel tank, 2 - Ventilation duct, 3 - Activated carbon tank, 4 - Fresh air vent,	5 — Regeneration valve, 6 - Connecting pipe to the suction pipe, 7 — Throttle valve, 8 — Suction pipe.