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Electrical Relay
Electrical relay is used to supply power to electric fuel
pump. When key switch is turned ON and all safety
switch requirements met, relay provides 12 volts to fuel
pump circuit. Fuel pump circuit is continuously grounded,
so pump is immediately activated and pressurizes
system.
Service
A malfunctioning relay can result in starting or operating
diffi culties. Relay and related wiring can be tested as
follows:
1. Disconnect relay connector plug from relay.
2. Connect black lead of VOA meter to a chassis
ground location. Connect red lead to #86 terminal in
relay connector. Set meter to test resistance (Rx1).
Turn key switch from OFF to ON. Meter should
indicate continuity (ground circuit is completed) for 1
to 3 seconds. Turn key switch back off .
a. Clean connection and check wiring if circuit was
not completed.
3. Set meter for DC voltage. Touch red tester lead to
#30 terminal in relay connector. A reading of 12 volts
should be indicated at all times.
4. Connect red lead of meter to #85 terminal in relay
connector. Turn key switch to ON position. Battery
voltage should be present.
a. No voltage present indicates a problem with key
switch, in wiring, or at connector.
b. If voltage is present, wiring to connector is good.
Turn ignition switch OFF and proceed to Step 5 to
test relay.
5. Connect an ohmmeter (Rx1 scale) between #85 and
#86 terminals in relay. There should be continuity.
6. Attach ohmmeter leads to #30 and #87 terminals in
relay. At fi rst, there should be no continuity. Using a
12 volt power supply, connect positive (+) lead to
#85 terminal and touch negative (–) lead to #86
terminal. When 12 volts is applied, relay should
activate and continuity should exist (circuit made)
between #30 and #87 terminals. Repeat test several
times. If, at any time relay fails to activate circuit,
replace relay.
66 690 14 Rev. A
Fuel Injectors
Explosive Fuel can cause fi res and severe
burns.
Fuel system ALWAYS remains under HIGH
PRESSURE.
Wrap a shop towel completely around fuel connector.
Press release button and slowly pull connector away
allowing shop towel to absorb any residual fuel in high
pressure fuel line. Any spilled fuel must be completely
wiped up immediately.
Details
B
C
E
H
A
Connection
C
Solenoid Winding
E
Valve Housing
G
Valve End
I
Director Plate
NOTE: Do not apply voltage to fuel injector(s).
Excessive voltage will burn out injector(s). Do
not ground injector(s) with ignition ON.
Injector(s) will open/turn on if relay is energized.
NOTE: When cranking engine with injectors
disconnected, fault codes will be registered in
ECU and will need to be cleared using software
fault clear or an ECU Reset and TPS Learn
Procedure.
Injector problems typically fall into three general
categories: electrical, dirty/clogged, or leakage. An
electrical problem usually causes one or both of injectors
to stop functioning. Several methods may be used to
check if injectors are operating.
1. With engine running at idle, listen for a buzzing or
clicking sound.
KohlerEngines.com
WARNING
D
F
G
I
Electrical
B
D
F
H
EFI System
A
Upper O-ring
Armature
Valve Seat
Lower O-ring
39
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