5B.25
Section 5B
EFI Fuel System
4. Verify that the governor has been set correctly.
With the linkage still retained in the “Full Throttle”
position (Step 2), unsnap the bushing clip,
separate the linkage from the bushing, and remove
the bushing from the lever. Follow Steps 3 and 4 in
‘‘Checking the Initial Adjustment’’.
5. Reconnect the dampening spring into its governor
lever hole from the bottom. Reinstall the bushing
and reattach the throttle linkage. See Figure
5B-34. Reattach the governor spring in the marked
hole.
6. Start the engine and allow it to fully warm up and
establish closed loop operation (approximately
5-10 min.). Check the speed settings and adjust
as necessary, first the low idle speed, and then the
high-speed setting.
Troubleshooting
General
When troubleshooting a problem on an engine with
EFI, basic engine operating problems must be
eliminated first before faulting the EFI system
components. What appears to be an EFI problem
could be something as simple as a fuel tank with
debris in the bottom or a plugged vent. Be sure the
engine is in good mechanical operating condition and
all other systems are operating properly before
attempting to troubleshoot the EFI system.
Troubleshooting Guide
Engine starts hard or fails to start when cold
1. Fuel pump not running
2. Faulty spark plugs
3. Old/stale fuel
4. Incorrect fuel pressure
5. Speed sensor loose or faulty
6. TPS offset incorrect (initialization)
7. TPS faulty
8. Engine temp sensor faulty
9. Faulty coils
10. Low system voltage
11. Faulty injectors
Engine starts hard or fails to start when hot
1. Faulty spark plugs
2. Fuel pump not running
3. Fuel pressure low
4. Insufficient fuel delivery
5. TPS offset incorrect (Initialization)
6. Speed sensor loose or faulty
7. TPS faulty
8. Engine temp sensor faulty
9. Faulty injectors
Engine stalls or idles roughly (cold or warm)
1. Faulty spark plugs
2. Insufficient fuel delivery
3. TPS offset incorrect
4. TPS faulty
5. Faulty engine temperature sensor
6. Faulty injectors
Engine misses, hesitates, or stalls under load
1. Fuel injector(s), fuel filter, fuel line, or fuel pick-up
dirty/restricted
2. Dirty air cleaner
3. Insufficient fuel pressure or fuel delivery
4. Vacuum (intake air) leak
5. Improper governor setting, adjustment or operation
6. Speed sensor malfunction
7. TPS faulty, mounting problem or "TPS Initialization
Procedure" incorrect
8. Bad coil(s), spark plug(s), or wires
Low Power
1. Faulty/malfunctioning ignition system
2. Dirty air filter
3. Insufficient fuel delivery
4. Improper governor adjustment
5. Plugged/restricted exhaust
6. One injector not working
7. Basic engine problem exists
8. TPS faulty or mounting exists
9. Throttle plates in throttle body/intake manifold not
fully opening to WOT stop (if so equipped)
Electrical System
The EFI system is a 12 VDC negative ground system,
designed to operate down to a minimum of 7.0 volts. If
system voltage drops below this level, the operation of
voltage sensitive components such as the ECU, fuel
pump, and injectors will be intermittent or disrupted,
causing erratic operation or hard starting. A fully
charged, 12 volt battery with a minimum of 350 cold
cranking amps is important in maintaining steady and
reliable system operation. Battery condition and state
of charge should always be checked first when
troubleshooting an operational problem.
Kohler Engine Parts Call K&T 606-678-9623 or 606-561-4983
www.mymowerparts.com
