JLG 450A_AJ Series II Service Manual - Manual (Page 172)

SECTION 3 - CHASSIS & TURNTABLE
3-122 – JLG Lift – 3121180
HEATED COOLANT MAY SPILL OUT DUE TO AIR “BURPING” OUT
OF SYSTEM WITH RADIATOR CAP OFF WITH ENGINE RUNNING
OR WHEN SHUTTING OFF ENGINE.
5. Verify two coolant hoses on the EPR are warm. If
they are not warm repeat step 3 and 4, otherwise
continue to step 6.
A PROPERLY PURGED COOLING SYSTEM WILL YIELD A WARM
UPPER RADIATOR HOSE AND A WARM EPR HOSE. IF UPPER
RADIATOR HOSE AND/OR EPR HOSE ARE NOT WARM TO THE
TOUCH AFTER ENGINE HAS RUN FOR 5-8 MINUTES AFTER
REACHING OPERATING TEMPERATURE, SYSTEM MAY STILL
CONTAIN AIR. IT MAY BE NECESSARY TO REPEAT ABOVE STEPS.
6. Fill radiator with coolant as needed and install radia-
tor cap. Remove cap off coolant recovery bottle and
fill just below HOT FULL line. Reinstall caps.
3.18 GM ENGINE DUAL FUEL SYSTEM
The Dual Fuel system allows the operator to operate the
vehicle on either gasoline or LPG by positioning a selector
switch in the operator's platform. When the operator
places the selector switch in gasoline mode, the gasoline
fuel pump is energized. While in gasoline mode the LPG
fuel lock-off is isolated and will not energize. In addition,
the gasoline injector circuit is enabled and injector pulses
are provided to each injector and the ECM calibration for
gasoline is also enabled. When the operator selects the
LPG mode the Low Pressure LPG lock-off is energized
and fuel from the LPG tank flows to the Electronic Pres-
sure Regulator (EPR). The EPR receives an electronic sig-
nal to position the secondary lever for the start or run
positions and when the engine begins to crank the mixer
air valve will rise and fuel will begin flowing to engine. Dur-
ing this mode the gasoline fuel pump is isolated and will
not be activated.
Gasoline dual fuel system primary components are the
gasoline tank, electric fuel pump and filter, fuel supply line,
injector rail and injectors, and fuel pressure regulator.
The LPG dual fuel system primary components are the
LPG fuel tank, in-fuel filter, LPG Low Pressure lock-off,
Electronic Pressure Regulator (EPR), and fuel mixer mod-
ule. The LPG fuel system operates at pressures which
range from 14.0 inches (355.60 mm) of water column up
to 312 psi (21.5 BAR).
Components shared by both systems include the Elec-
tronic Throttle Control and ECM. The ECM contains a dual
calibration; one controls the gasoline fuel system during
gasoline operation and one controls the LPG fuel system
during LPG operation.
Fuel Filter
Propane fuel, like other fuels, is subject to contamination
from outside sources. Refueling and removal of the tank
from the equipment can inadvertently introduce dirt and
other foreign matter into the fuel system. It is therefore
necessary to filter the fuel prior to entering the fuel system
components downstream of the tank. An inline fuel filter is
installed in the fuel system to remove the dirt and foreign
matter from the fuel. The inline filter is replaceable as a
unit only. Maintenance of the filter is critical to proper fuel
system operation and should be replaced as Section 1. In
severe operating conditions more frequent replacement of
the filter may be necessary.
Electric Lock Off
The Electric Lock Off device is an integrated assembly.
When energized the solenoid opens the valve and allows
Propane fuel to flow through the device. The valve opens
during cranking and run cycles of the engine. Lock off
supply voltage is controlled by the ECM.
Figure 3-77. Electric Fuel Lock Off