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Diesel
fuel contains varying degrees of
entrained air in the form of foam on
the surface or suspended in the bulk
fluid as tiny bubbles. Additionally,
fuel is driven into the fuel pump by
atmospheric pressure, which is
usually only enough pressure flow to
fill the pump at idle speeds.
Consequently, at higher operating
RPM’s, the stock pump cavitates
producing vapor.
Air
and vapor are compressible. The
presence of air/vapor in the fuel
injector delays the pressure
build-up. |
This
delays the injection, resulting in
Retarded Injection Timing.
Retarded injection timing in a
diesel, just like bad spark plugs in
a gasoline engine, causes lost
power, poor fuel mileage, and an
increase in exhaust emissions.
Retarded Injection Timing caused by
air/vapor is the primary source of
the rough idle, lost power,
increased fuel consumption and
excessive exhaust emissions of the
diesel engine. |
Air/vapor in the injector can also
cause permanent damage in the form
of galling and pitting of the
barrel/plunger assembly and tip
erosion.
The
conventional vacuum feed fuel supply
system does nothing to remove
entrained air from the fuel. In
fact, it only makes things worse. As
the filter plugs with use, the
already inadequate fuel flow to the
engine is further reduced,
increasing cavitation and retarding
injection timing even more. |
