Fuel System - Mercedes-Benz 212 Sedan E-Class Service Manual

Fuel system

Fuel supply
Gasoline engines
An electric fuel pump with different performance is
used for fuel delivery in engines 272 and 273. In these
systems the fuel is pumped from the fuel tank into the
fuel distributor (fuel rail) by the pump according to
demand, in order to supply the injection valves. This is
done with the aid of a pump governor which regulates
the quantities in relation to the system pressure. The
two gasoline engines are equipped with a non-return
fuel system.
Fuel system in E 250 CDI with OM 651
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Introduction of the New E-Class, Model Series 212 Sedan
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– This printout will not be recorded by the update service. Status: 01 / 2009 –
Diesel engines
The fuel supply in engines 651 and 642 is provided via
a high-pressure pump, which is supplied by an electri-
cally controlled fuel pump in the fuel tank.
The electric fuel pump used is a positive-displacement
pump based on the roller cell principle which has been
adapted to suit the volume requirements and system
pressure of the high-pressure pump.
The fuel supply system is equipped with one feed line
and one return line, and it is via the feed line that the
electric fuel pump delivers the scavenging quantity of
the high-pressure pump and the full-load consumption
of the engine. The surplus fuel is directed back to the
tank via the return line.
P47.00-2170-00