Engine Maintenance
114
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
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.
b. Momentarily energize the pull-in coil by
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, 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 red wire (8D—pin A)
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 ohmmeter
between the red wire (8D—pin A) and the
black wire (CHF—pin C) in the fuel
solenoid connector. 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.
Fuel Solenoid Replacement
1. Disconnect the fuel solenoid wire connector
from the main/unified wire harness and
remove the old fuel solenoid.
2. Connect the new fuel solenoid wire connector
to the main wire harness.
3. Press the
O
N
key to turn the unit on.
4. Use the microprocessor keypad to enter the
Output Test Mode. Refer to the appropriate
Microprocessor Diagnostic Manual for
specific information about the Output Test
Mode.
5. Energize the fuel solenoid by energizing the
run relay with the Output Test Mode.
NOTE: The fuel solenoid must be energized
when it is installed. If not, the plunger and
the linkage may not line up correctly and the
fuel solenoid will not function properly.
6. Place the O-ring in the groove in the end of
the fuel injection pump. Make sure that the
O-ring is positioned correctly during
installation to avoid damage and leaks.
7. Install the new fuel solenoid.
8. Press the
O
FF
key to turn the unit off after
installing the fuel solenoid.
Trochoid Feed Pump
The TK486V25 engine has a trochoid feed pump
on the fuel injection pump. The trochoid feed
pump supplies fuel to the injection pump at a
pressure of 65 to 87 psi (450 to 600 kPa). Check
the outlet pressure of the trochoid feed pump by
removing the plug and attaching a pressure gauge
to the port shown in Figure 189. The plug has
M12x1.25 threads. You will have to make an
adaptor to attach a pressure gauge. Replace the
trochoid feed pump if the outlet pressure is below
the pressure specifications in the following table.
1.
Fuel Solenoid
2.
O-ring
3.
Groove in Fuel Injection Pump
Figure 188: Fuel Solenoid Components
Trochoid Feed Pump Outlet Pressure
Cranking
15-30 psi (103-206 kPa)
Low Speed
30-50 psi (206-345 kPa)
High Speed
65-87 psi (450-600 kPa)
AEA635
