JLG 340AJ, Service And Maintenance Manual

Page: 118 / 370

SECTION 3 - CHASSIS & TURNTABLE
3-76 – JLG Lift – 3121259
PROPORTIONAL FUEL RACK ACTUATOR
The Proportional Fuel Rack Actuator controls engine speed
whenever the Control System calls for an engine RPM between
Idle and High Engine. It is energized by the J1-1 terminal on
the Ground Control Module. When the terminal is de-ener-
gized, the actuator fully extends and shuts down the engine.
Engine Start
To engage the engine starter, the Ground Module energizes
the J1-11 terminal to activate the start relay, which in turn,
energizes the starter solenoid.
Alternator Excitation
For the alternator to charge, it must be rotating and the alter-
nator excitation terminal must be energized by an external
power source. This power is supplied by the Ground Module
through terminal J1-32 to the D+ terminal on the alternator.
This terminal includes a one-way blocking diode that prevents
reverse energy flow into the Ground Module during engine
power-down. This terminal is continuously energized after
startup.
Fuel Pump
The Kubota fuel pump is mechanical and has no interaction
with the JLG Control System.
Shutdown
If the JLG Control System determines that the engine should
be shut down and not allowed to run, the Ground Module
takes the following steps to shut down the engine.
1. Remove power and prevent power from flowing to the
Proportional Fuel Rack Actuator by turning off output
terminal J1-1.
2. Remove power and prevent power from flowing to the
Engine Throttle Actuator by turning off output terminal
J1-2.
VBatt
J1-1 put Out
J3-1
Current
Sense
Proportional Fuel Rack Actuator
Ground Module
Fuel Rack
Actuator
Figure 3-59. Proportional Fuel Rack Actuator Sche-
matic
VBatt
J1-11
put Out
Starter
VBatt
Start Relay
Ground Module
- +
Figure 3-60. Engine Starter Schematic
VBatt
J1-32 put Out
Alternator
Ground Module
D+
Figure 3-61. Alternator Schematic