Electrical Maintenance
54
2. Disconnect wires RPM+ and RPM- from the
sensor.
Figure 28: RPM+ and RPM- Wires
3. Place the unit in Continuous Run. Run the unit
on low speed and high speed. Check the AC
voltage output across the sensor terminals.
Use a meter with a high ohms per volt internal
resistance. A Simpson 260, Fluke digital or
any good VOM will work. However, an
automotive type meter may not give an
accurate reading because the meter may load
the circuit heavily and cause the voltage level
to appear lower than it actually is.
a. The output voltage should be 1.0 to
2.0 Vac on low speed.
b. The output voltage should be 2.0 to
2.5 Vac on high speed.
NOTE: If the voltage is slightly off, the
voltage may be increased by turning the
sensor in more, and the voltage may be
lowered by turning the sensor out more.
4. Reconnect RPM+ and RPM- wires on RPM
sensor.
If the RPM sensor passes the above test, the
sensor may be considered good.
If the unit is not available, an alternate less
reliable test may be performed as follows:
Disconnect the sensor from all wires, and measure
the resistance across the terminals and from each
terminal to the aluminum case. The resistance
should be 250 to 300 ohms across the terminals,
and there should be no continuity from each
terminal to the case.
Glow Plugs
Glow plugs heat the combustion chamber to aid in
quick starting. The glow plugs are energized when
the microprocessor initiates unit start-up. A
defective glow plug (burned out) can be detected
by placing an external ammeter in series with the
plugs. Normal current draw is approximately
21 to 25 amps when preheating. A current draw of
21 to 25 amps means all three glow plugs are
working. If the current draw is less than 21 amps
on Preheat, at least one glow plug is bad.
To isolate an open circuit glow plug, remove the
jumper bar and test each glow plug individually
with an ohmmeter or a jumper wire and ammeter.
Each glow plug should have a resistance of
approximately 1.5 ohms or a current draw of
about 8 amps.
With an external ammeter connected in series, a
shorted glow plug will show excessive current
flow (more than 12 amps) when the Preheat
switch is pressed or when CB1 circuit breaker is
tripped, check each plug.
1.
Ohmmeter
2.
1.5 Ohms
3.
Remove Bar
Figure 29: Glow Plug Test
Summary of Contents for 919180
Page 4: ...4...
Page 10: ...Table of Contents 10...
Page 32: ...Unit Description 32 Unit Photographs Figure 3 Front View Figure 4 Back View AJA584 AJA585...
Page 33: ...Unit Description 33 Figure 5 Left Side View Figure 6 Right Side View AJA586 AJA58...
Page 35: ...Unit Description 35 Figure 8 North American Power Receptacle Box AJA58...
Page 38: ...Unit Description 38...
Page 58: ...Electrical Maintenance 58...
Page 66: ...Engine Maintenance 66 Figure 37 Fuel and Oil System Components...
Page 84: ...Engine Maintenance 84...
Page 96: ...Refrigeration Maintenance 96...
Page 118: ...Hilliard Clutch Maintenance 118...
Page 136: ...Cycle Diagrams 136...
Page 140: ...Wiring and Schematic Diagrams Index 140...
Page 141: ...141 Truck S Model SR 30 Schematic Diagram Page 1 of 2...
Page 142: ...142 Truck S Model SR 30 Schematic Diagram Page 2 of 2...
Page 143: ...143 Truck S Model 30 Units with P T Wiring Diagram Page 1 of 2...
Page 144: ...144 Truck S Model 30 Units with P T Wiring Diagram Page 2 of 2...
Page 145: ...145 Truck S Model 50 Schematic Diagram Page 1 of 2...
Page 146: ...146 Truck S Model 50 Schematic Diagram Page 2 of 2...
Page 147: ...147 Truck S Model 50 Units with P T Wiring Diagram Page 1 of 2...
Page 148: ...148 Truck S Model 50 Units with P T Wiring Diagram Page 2 of 2...