Injector Inspection Points - Kohler command pro ECH749 Service Manual

Injector Inspection Points

A Check for Leaks
1. Engine must be cool. Depressurize fuel system
through test valve in fuel rail.
2. Disconnect spark plug leads from spark plugs.
3. Remove air cleaner outer cover, inner wing nut,
element cover and air cleaner element/precleaner.
Service air cleaner components as required.
4. Remove screws securing air cleaner base to throttle
body manifold. Remove air cleaner base to permit
access to injectors. Check condition of air cleaner
base gasket, replace if necessary.
5. Remove fl ywheel screen if it overlaps blower
housing.
6. If engine has a radiator-type oil cooler mounted to
blower housing, remove oil cooler mounting screws.
7. Remove blower housing mounting screws. Note
location of plated (silver) screw attaching rectifi er/
regulator ground lead. Remove blower housing.
8. Thoroughly clean area around and including throttle
body/manifold and injectors.
9. Disconnect throttle linkage and damper spring from
throttle lever. Disconnect TPS lead from harness.
10. Remove manifold mounting bolts and separate
throttle body/manifold from engine leaving TPS, fuel
rail, air baffl e, injectors and line connections intact.
Discard old gaskets.
11. Position manifold assembly over an appropriate
container and turn key switch ON to activate fuel
pump and pressurize system. Do not turn switch to
START position.
12. If either injector exhibits leakage of more than two to
four drops per minute from tip, or shows any sign of
leakage around outer shell, turn ignition switch off
and replace injector as follows.
13. Depressurize fuel system following procedure in fuel
warning on page. Remove fuel rail mounting screws.
14. Clean any dirt accumulation from sealing/mounting
area of faulty injector(s) and disconnect electrical
connector(s).
15. Pull retaining clip off top of injector(s). Disconnect
fuel rail and remove injector(s) from manifold.
24 690 01 Rev. K
A
KohlerEngines.com
16. Reverse appropriate procedures to install new
injector(s) and reassemble engine. Use new
O-Rings any time an injector is removed (new
replacement injectors include new O-Rings).
Lubricate O-Rings lightly with oil. Torque fuel rail and
blower housing mounting screws to 3.9 N·m (35 in.
lb.), and intake manifold and air cleaner mounting
screws to 9.9 N·m (88 in. lb.).
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/stumble 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.
NOTE: Do not ground coils with ignition ON, as they
may overheat or spark.
Ignition Testing
1. Disconnect main harness connector from ECU.
"24 Pin" (MSE 1.0) Plastic-Cased ECU: Locate
pins #22 and #23 in 24 pin connector. See page .
"32 Pin" (MSE 1.1) Plastic Cased ECU: Locate
pins #30 and #31 in 32 pin connector. See page.
2. Disconnect connector from relay and locate terminal
#87 in connector.
3. Using an ohmmeter set on the Rx1 scale, check
resistance in circuits as follows:
"24 Pin" (MSE 1.0) Plastic-Cased ECU: Check
between terminal #87 and pin #22 for coil #1.
Repeat test between terminal #87 and pin #23 for
coil #2.
"32 Pin" (MSE 1.1) Plastic-Cased ECU: Check
between terminal #87 and pin #30 for coil #1.
Repeat test between terminal #87 and pin #31 for
coil #2.
A reading of 1.8-4.0 Ω in each test indicates that
wiring and coil primary circuits are OK.
a. If reading(s) are not within specifi ed range, check
and clean connections and retest.
b. If reading(s) are still not within specifi ed range,
test coils separately from main harness as
follows:
1. Disconnect red and black primary leads from
coil terminals.
2. Connect an ohmmeter set on the Rx1 scale to
primary terminals. Primary resistance should
be 1.8-2.5 Ω.
EFI SYSTEM-BOSCH
69