Thermo King SGCO 3000, Manual

Page: 101 / 144

Engine Maintenance
101
If you suspect that the engine does not operate
because the fuel solenoid is not operating
correctly, use the following procedure:
1. Check the operation of the fuel hold relay and
the fuel pull relay.
a. Go to the Commands Menu and use the
PTI submenu or the Manual Function Test
submenu to test the relays. See
“Commands Menu” on page 58, “PTI” on
page 59, and “Manual Function Test” on
page 60.
b. If a relay fail the test, replace the relay.
c. If the relays pass the tests, go to step 2.
2. Disconnect wire 8S from the starter solenoid.
3. Disconnect the fuel solenoid wire connector
from the main wire harness.
4. Place the Unit On/Off switch in the “ON”
position.
5. Check the voltage on 8D circuit in the main
wire harness connector for the fuel solenoid.
Refer to Figure 64 or the unit wiring diagram
to identify the pins in the wire harness and
fuel solenoid connectors.
a. If battery voltage is not present on the 8D
circuit, check the 8D circuit and related
components for a fault.
b. If battery voltage is present on the 8D
circuit, go to step 6.
6. Check CH circuit in the main wire harness at
the fuel solenoid connector for continuity to a
good chassis ground.
a. If there is no continuity between CH
circuit and a good chassis ground, check
the CH wire for an open circuit.
b. If there is continuity between CH circuit
and a good chassis ground, go to step 7.
7. Turn the unit off.
8. Place a jumper wire between the CH circuit in
the connector on the fuel solenoid and a good
chassis ground.
9. Test the pull-in coil by momentarily placing a
jumper between the 8DP circuit pin in the
connector on the fuel solenoid and the positive
battery terminal. The fuel solenoid should
make a definite click when the pull-in coil is
energized. It should click again when the
pull-in coil is de-energized.
NOTE: The pull-in coil may draw 35 to 45
amperes so do not leave the jumper
connected to pin 8DP for more than a few
seconds.
a. If the pull-in coil does not energize, check
the resistance of the pull-in coil by placing
an ohmmeter between 8DP circuit and the
CH circuit in the connector on the fuel
solenoid. The resistance of the pull-in coil
should be 0.2 to 0.3 ohms. Replace the
fuel solenoid if the resistance of the pull-in
coil is not in this range.
b. If the pull-in coil does energize, go to
step 10.
10. Test the hold-in coil.
a. Energize the hold-in coil by placing a
jumper between the 8D circuit in the
connector to the fuel solenoid and the
positive battery terminal.
b. Momentarily energize the pull-in coil by
placing a jumper between the 8DP circuit
in the connector to the fuel solenoid and
the positive battery terminal. The fuel
solenoid should make a definite click
when the pull-in coil is energized, but
should not click when the pull-in coil is
de-energized.
c. De-energize the hold-in coil by removing
the jumper from the 8D circuit and the
positive battery terminal. The fuel
solenoid should make a definite click
when the hold-in coil is de-energized.
d. If the hold-in coil does not function
properly, check the resistance of the
hold-in coil by placing an ohm-meter
between the 8D circuit and the CH circuit
in the connector to the fuel solenoid. The
resistance of the hold-in coil should be 24
to 29 ohms. If the resistance of the hold-in
coil is not in this range, replace the fuel
solenoid.