Fuel Components - Kohler ECV940 Service Manual

EFI SYSTEM-ELECTRONIC THROTTLE BODY (ETB)
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.
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
8000-18000 Ω.
d. If secondary resistance is not within specifi ed
range, coil is faulty and needs to be replaced.
Ignition coils can be tested using KOHLER
System (KDS) Gen 2, see Tools and Aids. Select Ignition
Coil test #1 or #2 and follow instructions in help (?) area
of test.
42

FUEL COMPONENTS

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, fuses are good. If
required, testing of fuel pump may be conducted.
FPM can be tested using KOHLER
(KDS) Gen 2, see Tools and Aids. Select Fuel Pump Test
and follow instructions in help (?) area of test.
NOTE: Fuel pump module pins are coated with a thin
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/
power down 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
4. If pump did not activate (step 3), confi 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
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WARNING
Explosive Fuel can cause fi res and severe
burns.
Fuel system ALWAYS remains under HIGH
PRESSURE.
layer of electrical grease to prevent fretting and
corrosion. Do not attempt to remove electrical
grease from fuel pump module pins.
troubleshooting.
on key switch and confi rm battery voltage is
present during six second prime process.
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