Service manual

3-30 FUEL SYSTEM (DFI)
DFI System Troubleshooting Guide
Symptoms or possible Causes Actions (chapter)
Valvespringbrokenorweak
Inspect and replace (see chapter 5).
Valve not seating properly (valve bent, worn or
carbon accumulating on seating surface)
Inspect and repair or replace (see chapter 5).
Poor Running at Low Speed
Symptoms or Possible Causes Actions (chapter)
Spark weak:
Battery voltage low
Inspect and charge (see chapter 16).
Spark plug dirty, broken or gap maladjusted Replace (see chapter 2).
Ignition coil trouble Inspect the ignition coil (see chapter 16).
Ignition coil shorted or not in good contact Reinstall or inspect ignition coil (see chapter 16).
Spark plug incorrect Replace it with the correct plug (see chapter 16).
IC igniter in ECU trouble Inspect (see c hapter 16).
Crankshaft sensor trouble Inspect (see c hapter 16).
Igni
tion coil trouble
Inspect (see chapter 16).
Fuel/air mixture incorrect:
Little fuel in tank Supply fuel (see Owner’s Manual).
Air cleaner clogged, poorly sealed, or missing Clean element or inspect sealing (see chapter
2, 3).
Air cleaner duct loose Reinstall (see chapter 3).
Air c leaner O-ring damaged Replace (see chapter 3).
Fuel tank air vent obstructed Inspect and repair (see chapter 3).
Throttle body assy loose
Reinstall (see chapter 3).
Fuel filter or pump screen clogged Inspect and replace fuel pump (see chapter 3).
Fuel pressure regulator clogged
Inspect fuel pressure and replace fuel pump (see
chapter 3).
Fuel line clogged
Inspect and repair (see chapter 3).
Inlet air pressure sensor trouble Inspect (see chapter 3).
Inlet air temperature sensor trouble Inspect (see chapter 3).
Unstable (rough) idling:
ISC valve trouble Inspect (see chapter 3).
Fuel injector trouble
Inspect (see chapter 3).
Throttle sensor trouble
Inspect (see chapter 3).
Crankshaft sensor trouble Inspect (see chapter 3).
Throttle valves not synchronizing Inspect (see chapter 2).
Inlet air temperature sensor trouble Inspect (see chapter 3).
Water temperature sensor trouble Inspect (see chapter 3).
Fuel pressure too low or too high
Inspect (see chapter 3).
Battery voltage low
Inspect and charge (see chapter 16).
Incorrect idle speed:
Water temperature sensor trouble
Inspect (see chapter 3).
Throttle sensor trouble
Inspect (see chapter 3).
ISC valve trouble Inspect (see chapter 3).
Engine stalls easily:
Fuel pump trouble
Inspect (see chapter 3).