Kohler Command PRO ECH630 Service Manual page 49

The injectors have sequential fueling that open and
close once every other crankshaft revolution. The
amount of fuel injected is controlled by the ECU
and determined by the length of time the valve
needle is held open, also referred to as the injection
duration or pulse width. The time the injector is open
(milliseconds) may vary in duration depending on the
speed and load requirements of the engine.
2
3
5
6
8
1. Electrical Connection
2. Upper O-ring
3. Solenoid Winding
4. Armature
5. Valve Housing
Figure 5-13. Fuel Injector Details.
Service
Injector problems typically fall into three general
categories: electrical, dirty/clogged, or leakage. An
electrical problem usually causes one or both of the
injectors to stop functioning. Several methods may be
used to check if the injectors are operating.
1. With the engine running at idle, listen for a
buzzing or clicking sound.
2. Disconnect the electrical connector from an
injector and listen for a change in idle
performance (only running on one cylinder) or a
change in injector noise or vibration.
If an injector is not operating, it can indicate either a
bad injector, or a wiring/electrical connection problem.
Check as follows:
1
4
7
9
6. Valve Seat
7. Valve End
8. Lower O-ring
9. Director Plate
NOTE: Do not apply voltage to the fuel injector(s).
Excessive voltage will burn out the
injector(s). Do not ground the injector(s) with
the ignition ON. Injector(s) will open/turn on
if relay is energized.
1. Disconnect the electrical connector from both
injectors. Plug a 12 volt noid light (part of EFI
Service Kit, see Section 2) into one connector.
Figure 5-14. Volt Noid Light.
2. Make sure all safety switch requirements are met.
Crank the engine and check for fl ashing of the
test light. Turn key OFF for at least 10 seconds
between tests to allow ECU to go to sleep and
reawake. Repeat test at other connector.
NOTE: When cranking engine with injectors
disconnected, fault codes will be registered
in the ECU and will need to be cleared using
soft ware fault clear or an ECU Reset and TPS
Learn Procedure.
a. If fl ashing occurs, use an ohmmeter (Rx1
scale) and check the resistance of each injector
across the two terminals. Proper resistance is
11-13 . If injector resistance is correct, check
whether the connector and injector terminals
are making a good connection. If the
resistance is not correct, replace the injector.
Check all electrical connections, connectors, and
wiring harness leads if resistance is incorrect.
Section 5
EFI Fuel System
5.17
5