Fuel Components; Ignition Coil; Fuel Pump Module (Fpm) - Kohler command pro ECH749 Service Manual

7. Reverse appropriate procedures to install new
injector(s) and reassemble engine. Use new O-rings
and retaining clips any time an injector is removed
(new replacement injectors include new O-rings and
retaining clips). Lubricate O-rings lightly with clean
engine oil. Use installation tool provided with O-rings
to install new upper O-ring. Place tool into fuel
injector inlet. Place one side of O-ring into O-ring
groove and roll O-ring over tool onto fuel injector.
Torque screw securing fuel injector caps and blower
housing mounting screws to 7.3 N·m (65 in. lb.), and
intake manifold and air cleaner mounting screws to
10.5 N·m (93 in. lb.). An ECU Reset will need to be
completed.
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 Coil

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 spark plug lead from spark
plug 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 0.5-0.8 
2. If reading(s) are not within specifi ed range, check
and clean connections and retest.
3. If reading(s) are still not within specifi ed range, test
coils separately from main harness as follows:
a. Remove screw retaining coil to housing and
disconnect primary leads connector.
24 690 01 Rev. K
b. Connect an ohmmeter set on Rx1 scale to
primary terminals of coil. Primary resistance
should be 0.5-0.8 Ω.
c. Connect an ohmmeter set on Rx10K scale
between spark plug boot terminal and B+ primary
terminal. Secondary resistance should be 6400-
7800 Ω.
d. If secondary resistance is not within specifi ed
range, coil is faulty and needs to be replaced.

FUEL COMPONENTS

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)

Fuel pump module is not serviceable and must be
replaced if determined to be faulty. If a fuel pump
problem is suspected, make certain pump is being
activated, all electrical connections are properly secured,
fuses are good, and a minimum of 7.0 volts is being
supplied. If during cranking, voltage drops below 7.0
volts, a reduction of fuel pressure may occur resulting in
a lean starting condition. If required, testing of fuel pump
may be conducted.
1. Relieve fuel pressure at fuel pump module. Fuel
pump module may need to be loosened or pulled
away from engine. Disconnect fuel coupler from fuel
pump module and insert pressure test jumper (from
Kohler EFI Service Kit) between high pressure fuel
line and fuel pump module.
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. If system pressure of 39
psi ± 3 is observed, wiring, fuel pump, and regulator
are working properly. Turn key switch OFF and
depress valve button on tester to relieve system
pressure.
a. If pressure is too high or too low, replace fuel
pump module.
4. If pump did not activate (step 3), disconnect plug
from fuel pump. Connect a DC voltmeter across
terminals in plug, turn on key switch and observe if a
minimum of 7 volts is present during six second
prime process.
5. If no voltage is observed, connect red lead of meter
to red wire of plug and black lead to a good ground
while key is still ON.
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47