37
19 690 01 Rev. --
KohlerEngines.com
EFI SYSTEM
Injector problems due to dirt or clogging are generally
unlikely due to design of injectors, high fuel pressure,
and detergent additives in gasoline. Symptoms that
could be caused by dirty/clogged injectors include
rough idle, hesitation/stumbling during acceleration, or
triggering of fault codes related to fuel delivery. Injector
clogging is usually caused by a buildup of deposits
on director plate, restricting
fl
ow of fuel, resulting in
a poor spray pattern. Some contributing factors to
injector clogging include higher than normal operating
temperatures, short operating intervals, and dirty,
incorrect, or poor quality fuel. Cleaning of clogged
injectors is not recommended; they should be replaced.
Additives and higher grades of fuel can be used as a
preventative measure if clogging has been a problem.
Ignition Coils
This engine is equipped with dual-plug coils. Either they
both
fi
re or neither will
fi
re. If a coil is determined to be
faulty, replacement is necessary. An ohmmeter may be
used to test wiring and coil windings.
NOTE: Do not ground primary coil with ignition ON as
they may overheat or spark.
NOTE: Always disconnect both spark plug leads from
spark plugs before performing following tests.
NOTE:
If ignition coil(s) are disabled and an ignition
fault is registered, system will automatically
disable corresponding fuel injector drive
signal.
Fault must be corrected to ignition coil
and ECU power (switch) must be turned OFF for
10 seconds for injector signal to return. This is a
safety measure to prevent bore washing and oil
dilution.
Testing
Using an ohmmeter set on Rx1 scale, check resistance
in circuits as follows:
1. To check cylinder coil 1 (starter side), disconnect
Black connector from ECU and test between Black
pins 1 and 15. To check cylinder coil 2 (oil
fi
lter side),
disconnect Grey connector from ECU and test
between Grey pins 10 and 17. Wiring and coil
primary circuits are OK if readings are 0.85-1.15
2. If reading(s) are not within speci
fi
ed range, check
and clean connections and retest.
3. If reading(s) are still not within speci
fi
ed range, test
coils separately from main harness as follows:
a. Remove mounting screws retaining coil and
disconnect primary leads connector.
b. Connect an ohmmeter set on Rx1 scale to
primary terminals of coil. Primary resistance
should be 0.85-1.15
Ω
.
c. Connect ohmmeter leads (set on Rx200K scale)
between both spark plug boot terminals.
Secondary resistance should be 15000-25000
Ω
.
d. If either primary or secondary resistance is not
within speci
fi
ed range, coil is faulty and needs to
be replaced.
FUEL COMPONENTS
WARNING
Explosive Fuel can cause
fi
res and severe
burns.
Fuel system ALWAYS remains under HIGH
PRESSURE.
Wrap a shop towel completely around fuel pump
module connector. Press release button(s) and slowly
pull connector away from fuel pump module allowing
shop towel to absorb any residual fuel in high pressure
fuel line. Any spilled fuel must be completely wiped up
immediately.
Fuel Pump Module (FPM)
FPM is not serviceable and must be replaced if
determined to be faulty. If a FPM problem is suspected,
make certain pump is being activated, all electrical
connections are properly secured and fuses are good. If
required, testing of FPM may be conducted.
1. Relieve fuel pressure at FPM. FPM may need to be
loosened or pulled away from engine. Press release
button(s) and slowly pull connector away from FPM
allowing shop towel to absorb any residual fuel in
high pressure fuel line. Insert pressure test jumper
(from Kohler EFI Service Kit) between high pressure
fuel line and FPM.
2. Connect black hose of Pressure Tester. Route clear
hose into a portable gasoline container or equipment
fuel tank.
3. Turn on key switch to activate pump and check
system pressure on gauge. It may take several key
cycles to compress air introduced into system and
reach regulated pressure. System pressure of 39 psi
± 3 should be present. Turn key switch OFF and
depress valve button on tester to relieve system
pressure.
a. If pressure is too high or too low, proceed to
troubleshooting.
4. If pump did not activate (step 3), con
fi
rm that safety
system on equipment is not active. One potential
cause of unnecessary FPM replacement may
involve measuring voltage at FPM electrical
connector. Using a Digital Volt Ohm Meter (DVOM)
will provide a reading near battery voltage, even
when ECU is not grounding FPM circuit.
a. Connect a DVOM across terminals in plug, turn
on key switch and con
fi
rm battery voltage is
present during six second prime process.
b. Test light con
fi
rmation: Turn key off. Disconnect
DVOM. Connect 12 volt test light across terminals
in plug. Key needs to remain off for a minimum of
30 seconds before proceeding. Turn key on.
Con
fi
rm test light illuminates for approximately 6
seconds. After approximately 6 seconds, test light
will remain off unless another prime cycle is
initiated.
