Kohler COMMAND CH18, Руководство по обслуживанию

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5B.20
Section 5B
EFI Fuel System
1. Connect the black hose of Pressure Tester (part of
EFI Service Kit, see Section 2), to the test valve in
the fuel rail. Route the clear hose into a portable
gasoline container or the equipment fuel tank.
2. Turn on the key switch to activate the pump and
check the system pressure on the gauge. If system
pressure of
39 psi ± 3 is observed, the relay, fuel
pump, and regulator are working properly. Turn
the key switch off and depress the valve button
on the tester to relieve the system pressure.
a. If the pressure is too high, and the regulator is
outside the tank (just down line from the
pump), check that the return line from the
regulator to the tank is not kinked or blocked.
If the return line is good, replace the regulator
(see ‘‘Regulator Service’’ on page 5B.21).
b. If the pressure is too low, install in-line ‘‘T’’
between the pump and regulator and retest
the pressure at that point. If it is too low there
also, replace the fuel pump.
3. If the pump did not activate (step 2), disconnect
the plug from the fuel pump. Connect a DC
voltmeter across the terminals in the plug, turn
on the key switch and observe if a minimum of 7
volts is present. If voltage is between 7 and 14,
turn key switch off and connect an ohmmeter
between the terminals on the pump to check for
continuity.
a. If there was no continuity between the pump
terminals, replace the fuel pump.
b. If the voltage was below 7, test the wiring
harness and relay as covered in the ‘‘Electrical
Relay’’ section.
4. If voltage at the plug was good, and there was
continuity across the pump terminals, reconnect
the plug to the pump, making sure you have a
good connection. Turn on the key switch and
listen for the pump to activate.
a. If the pump starts, repeat steps 1 and 2 to
verify correct pressure.
b. If the pump still does not operate, replace it.
Figure 5B-28. Internal Fuel Pressure Regulator.
General
The fuel pressure regulator assembly maintains the
required operating system pressure of
39 psi ± 3 . A
rubber-fiber diaphragm (see Figure 5B-29) divides the
regulator into two separate sections; the fuel chamber
and the pressure regulating chamber. The pressure
regulating spring presses against the valve holder
(part of the diaphragm), pressing the valve against the
valve seat. The combination of atmospheric pressure
and regulating spring tension equals the desired
operating pressure. Any time the fuel pressure against
the bottom of the diaphragm exceeds the desired (top)
pressure, the valve opens, relieving the excess
pressure, returning the excess fuel back to the tank.
Fuel Pressure Regulator
Figure 5B-27. External Fuel Pressure Regulators
with Base.