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17-20 APPENDIX
Troubleshooting Guide
NOTE
○
Refer to the Fuel System chapter for most
of DFI t
rouble shooting guide.
○
This is not an exhaustive list, giving every
possible cause for each problem listed. It
is mea
nt simply as a rough guide to assist
the troubleshooting for some of the more
common difficulties.
Engine Doesn’t Start, Starting
Difficulty:
Starter motor not rotating:
Starter lockout switch or neutral switch trou-
ble
Starter motor trouble
Battery voltage low
Starter relay not contacting or operating
Starter button not contacting
Wiring open or shorted
Ignition switch trouble
Engine stop switch trouble
Fuse blown
Starter motor rotating but engine doesn’t
turn over:
Starter clutch trouble
Vehicle-down sensor (DFI) coming off
Engine won’t turn over:
Valve seizure
Valve lifter seizure
Cylinder, piston seizure
Crankshaft seizure
Connecting rod small end seizure
Connecting rod big end seizure
Transmission gear or bearing seizure
Camshaft seizure
Starter idle gear seizure
No fuel flow:
No fuel in tank
Fuel pump trouble
Fuel tank air vent obstructed
Fuel filter clogged
Fuel line c logged
Engine flooded:
Clean spark plug and adjust plug gap
Starting technique faulty
(When flooded, do not crank the engine with
the throttle fully opened. This promotes
engine flood because more fuel is supplied
automatically by DFI.)
No spark; spark weak:
Vehicle-down sensor (DFI) coming off
Ignition switch not ON
Engine stop switch turned OFF
Clutch lever not pulled in or gear not in neu-
tral
Battery voltage low
Spark plug dirty, broken, or gap malad-
justed
Stick c
oil shorted or not in good contact
Stick coil trouble
Spark plug incorrect
IC igni
ter in ECU trouble
Camshaft position sensor trouble
Neutral, starter l ockout, or side stand switch
troubl
e
Crankshaft sensor trouble
Ignition switch or engine stop switch
shorted
Wiring shorted or open
Fuse blown
Fuel/ai
r mixture incorrect:
Bypass screw and/or idle adjusting screw
maladjusted
Air pass
age clogged
Air cleaner clogged, poorly sealed, or miss-
ing
Compres
sion Low:
Spark plug loose
Cylinder head not sufficiently tightened
down
No valve clearance
Cylinder, piston worn
Piston ri
ng bad (worn, weak, broken, or
sticking)
Piston ring/groove clearance excessive
Cylinde
r head gasket damaged
Cylinder head warped
Valvespringbrokenorweak
Valve not
seating properly (valve bent,
worn, or carbon accumulation on the
seating surface)
Poor Running at Low Speed:
Spark weak:
Battery voltage low
Spark plug dirty, broken, or maladjusted
Stick coil wiring trouble
Stick coil not in good contact
Spark plug incorrect
IC igniter in ECU trouble
Camshaft position sensor trouble
Crankshaft sensor trouble
Stick coil trouble
Fuel/air mixture incorrect:
Bypass screw maladjusted
Air passage clogged
Air bleed pipe bleed holes clogged
Pilot passage clogged
Air cleaner clogged, poorly sealed, or miss-
ing
Fuel tank air vent obstracted
Fuel pump trouble
Throttle body assy holder loose