JLG 340AJ Service Manual - Manual (Page 115)

SECTION 3 - CHASSIS & TURNTABLE
3121259 – JLG Lift – 3-75
The Ground Module calculates the length of time the glow
plugs are energized prior to startup based upon ambient tem-
perature, engine coolant temperature, and battery voltage.
Refer to Table 3-6, Glow Plug Conditions.
The glow plugs are deenergized if:
• The Engine State is Engine Cranking, Engine Starting,
Engine running
or
• The Emergency Descent Mode is activated and Lift Down,
Tower Lift Down, or Jib Lift Down are active.
If the STARTER LOCKOUT option is enabled in the Machine
Setup, the Ground Module will not allow an engine start
attempt until the glow plug time has expired. If this option is
not enabled, the glow plug time can be interrupted and an
engine start attempt can be made. Starter Lockout is only
applicable for the first glow plug cycle.
Engine Speed Actuators
Engine speed on the Kubota engine is controlled by two actu-
ators; a throttle actuator that is On/Off operated (moves the
throttle arm between the Idle and High Engine positions) and
a proportional fuel rack actuator that limits the opening of the
fuel rack to control speeds between the Idle and High Engine
positions. The two actuators function together to achieve
smooth engine speed transitions. Refer to Table 3-7, Engine
Actuator Conditions.
ENGINE THROTTLE ACTUATOR
The Ground Module energizes the Throttle Actuator Relay
through terminal J1-2 if the engine is cranking or starting and
the Control System is calling for Idle RPM.
Table 3-6. Glow Plug Conditions
Engine Coolant
Temperature
Battery
Voltage Ambient
Temperature
Glow Plug
Time On
Greater than or
equal to
122 º F (50 º C)
- - - - Off
- - Less than 11V - - Off
Less than
122 º F (50 º C)
Greater than
11V
Greater than
59ºF(15ºC)
Off
Less than
122 º F (50 º C)
Greater than
11V
Temp Between
23ºF and 59ºF
(-5ºC and 15ºC)
On for
10 sec.
Less than
122 º F (50 º C)
Greater than
11V
Temp Between
5ºF and 23ºF
(-15ºC and -5ºC)
On for
15 sec.
Less than
122 º F (50 º C)
Greater than
11V
Temp Less
Than
5ºF (-15ºC)
On for
20 sec.
Table 3-7. Engine Actuator Conditions
Engine RPM
Level
Throttle
Actuator
Fuel Rack Actuator
Idle Off Energized/Fully Retracted
Between Idle RPM
and
High Engine RPM
On Energized/Control Loop
High Engine On Energized/Fully Retracted
VBatt
J1-2 put Out
30A Fuse
Throttle
Actuator
Throttle
Actuator Relay
Ground Module
- +
Figure 3-58. Engine Throttle Actuator Schematic