Thermo King SB-210, Manual

Page: 89 / 159

Engine Maintenance
89
Testing the Fuel Solenoid
NOTE: The fuel solenoid pull-in coil will
require 35 to 45 amps to turn on the fuel. The
unit’s battery must be in good condition. If the
battery has enough power to crank the engine
over, it has enough power to energize the fuel
solenoid pull-in coil.
If you suspect that the engine does not run
because the fuel solenoid is not operating
correctly, use the following procedure:
1. Use the microprocessor keypad to enter the
Interface Board Test Mode. Refer to the
appropriate Microprocessor Diagnostic
Manual for specific information about the
Interface Board Test Mode.
2. Energize the run relay with the Interface
Board Test Mode. The fuel solenoid relay is
momentarily energized when the run relay is
energized with the Interface Board Test Mode.
This energizes the fuel solenoid, which makes
a definite click when energized.
3. De-energize the run relay with the Interface
Board Test Mode. This de-energizes the fuel
solenoid, which makes a definite click when
de-energized.
4. Repeat steps 2 and 3 a few times to check the
operation of the fuel solenoid.
NOTE: The fuel solenoid may be removed
from the injection pump to visually check its
operation. The fuel solenoid must be
energized when it is re-installed in the
injection pump. If it is not, the plunger and
the linkage may not line up correctly and the
fuel solenoid will not function properly.
5. If the fuel solenoid is not operating properly,
check the run relay (K1), the fuel solenoid pull
in relay (K6), their fuses, and the associated
circuits. If the relays, fuses and circuits are
acceptable, use steps 6 through 9 to isolate and
check the fuel solenoid.
6. Disconnect the fuel solenoid wire connector
from the main wire harness.
7. Place a jumper wire between the black wire
(CH—pin C) in the fuel solenoid connector
and a good chassis ground.
8. Test the pull-in coil by momentarily placing a
jumper between the white wire (8DP—pin B)
in the fuel solenoid connector and the positive
battery terminal. The fuel solenoid should
make a definite click when the pull-in coil is
energized and should click again when the
pull-in coil is de-energized.
NOTE: The pull-in coil will draw 35 to 45
amps so do not leave the jumper connected to
the white wire (8DP—pin B) 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 the white wire
(8DP—pin B) and the black wire (CH—
pin C) in the fuel solenoid connector. The
resistance of the pull-in coil should be 0.2
to 0.3 ohms. If the resistance of the pull-in
coil is not in this range, replace the fuel
solenoid.
b. If the pull-in coil does energize, go to
step 9.
9. Test the hold-in coil.
a. Energize the hold-in coil by placing a
jumper between the red wire (8D—pin A)
in the fuel solenoid connector and the
positive battery terminal.
1. Red (8D)
2. White (8DP)
3. Black (CH)
Figure 78: Fuel Solenoid
Connector Pin Identification
AEA633