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). |
Stick coil trouble | Inspect the stick coil (see chapter 16). |
Stick coil shorted or not in good contact | Reinstall or inspect stick coil (see chapter 16). |
Spark plug incorrect | Replace it with the correct plug (see chapter 16). |
IC igniter in ECU trouble | Inspect (see chapter 16). |
Crankshaft sensor trouble | Inspect (see chapter 16). |
Stick 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 cleaner 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). |
Throttle body assy O-ring damage | Replace (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). |
Thermostat trouble | Inspect and replace (see chapter 4). |
Unstable (rough) idling: | |
Fuel injector trouble | Inspect (see chapter 3). |
Main 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). |
Main throttle sensor trouble | Inspect (see chapter 3). |
Engine stalls easily: | |
Fuel pump trouble | Inspect (see chapter 3). |
Fuel injector trouble | Inspect (see chapter 3). |
Main throttle sensor trouble | Inspect (see chapter 3). |
Fuel pressure too low or too high | Inspect (see chapter 3). |
Inlet air pressure sensor trouble | Inspect (see chapter 3). |
Water temperature sensor trouble | Inspect (see chapter 3). |
Inlet air temperature sensor trouble | Inspect (see chapter 3). |
Fuel line clogged | Inspect and repair (see chapter 3). |
Fuel pressure too low or too high | Inspect (see chapter 3). |
Fuel pressure regulator trouble | Inspect fuel pressure and replace fuel pump (see chapter 3). |
Crankshaft sensor trouble | Inspect (see chapter 16). |
Stick coil trouble | Inspect (see chapter 16). |
Compression Low: | |
Spark plug loose | Reinstall (see chapter 16). |
Cylinder head not sufficiently tightened down | Tighten (see chapter 5). |
No valve clearance | Adjust (see chapter 2). |
Cylinder, piston worn | Inspect and replace (see chapter 5). |
Piston ring bad (worn, weak, broken or sticking ) | Inspect and replace (see chapter 5). |
Piston ring/groove clearance excessive | Inspect and replace (see chapter 5). |
Cylinder head gasket damaged | Replace (see chapter 5). |
Cylinder head warped | Inspect and replace (see chapter 5). |
Valve guide worn or stem seal damaged | Inspect and replace (see chapter 5). |
Valve spring broken or weak | 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). |
Camshaft cam worn | Inspect and replace (see chapter 5). |
Hesitation: | |
Too low fuel pressure | Inspect (see chapter 3). |
Clogged fuel line | Inspect and repair (see chapter 3). |
Cracked or obstructed inlet air pressure sensor hose | Inspect and repair or replace (see chapter 3). |
Fuel pump trouble | Inspect (see chapter 3). |
Fuel injector trouble | Inspect (see chapter 3). |
Inlet air temperature sensor trouble | Inspect (see chapter 3). |
Main throttle sensor trouble | Inspect (see chapter 3). |
Subthrottle sensor trouble | Inspect (see chapter 3). |
Subthrottle valve actuator trouble | Inspect (see chapter 3). |
Water temperature sensor trouble | Inspect (see chapter 3). |
Inlet air pressure sensor trouble | Inspect (see chapter 3). |
Loose injector connectors | Remedy (see chapter 3). |
Crankshaft sensor trouble | Inspect and repair or replace (see chapter 16). |
Stick coil trouble | Inspect and repair or replace (see chapter 16). |
Loose terminal of battery (-) cable or engine ground lead | Inspect and repair (see chapter 16). |
Delay of ignition timing | Inspect crankshaft sensor and IC igniter in ECU (see chapter 16). |
Poor acceleration: | |
Too low fuel pressure | Inspect (see chapter 3). |
Water or foreign matter in fuel | Change fuel. Inspect and clean fuel system (see chapter 3). |
Clogged fuel filter or pump screen | Inspect and replace fuel pump (see chapter 3). |
Fuel pump trouble | Inspect (see chapter 3). |
Fuel injector trouble | Inspect (see chapter 3). |
Inlet air temperature sensor trouble | Inspect (see chapter 3). |
Water temperature sensor trouble | Inspect (see chapter 3). |
Subthrottle sensor trouble | Inspect (see chapter 3). |
Subthrottle valve actuator trouble | Inspect (see chapter 3). |
Stick coil trouble | Inspect and replace (see chapter 16). |
Engine oil level to high | Repair (see chapter 7). |
Spark plug dirty, broken or gap maladjusted | Replace (see chapter 2). |
Stumble: | |
Too low fuel pressure | Inspect (see chapter 3). |
Fuel injector trouble | Inspect (see chapter 3). |
Main throttle sensor malfunction | Inspect (see chapter 3). |
Subthrottle sensor trouble | Inspect (see chapter 3). |
Subthrottle valve actuator trouble | Inspect (see chapter 3). |
Water temperature sensor trouble | Inspect (see chapter 3). |
Inlet air pressure sensor trouble | Inspect (see chapter 3). |
Surge: | |
Unstable fuel pressure | Fuel pressure regulator trouble (Inspect and replace fuel pump) or kinked fuel line (Inspect and repair fuel line) (see chapter 3). |
Fuel injector trouble | Inspect (see chapter 3). |
Water temperature sensor trouble | Inspect (see chapter 3). |
Backfiring when deceleration: | |
Spark plug dirty, broken or gap maladjusted | Replace (see chapter 2). |
Too low fuel pressure | Inspect (see chapter 3). |
Fuel pump trouble | Inspect (see chapter 3). |
Main throttle sensor trouble | Inspect (see chapter 3). |
Inlet air temperature sensor trouble | Inspect (see chapter 3). |
Water temperature sensor trouble | Inspect (see chapter 3). |
Inlet air pressure sensor trouble | Inspect (see chapter 3). |
Air switching valve broken | Inspect and replace (see chapter 5). |
Air suction valve trouble | Inspect and replace (see chapter 5). |
After fire: | |
Crankshaft sensor trouble | Inspect (see chapter 16). |
Spark plug burned or gap maladjusted | Replace (see chapter 2). |
Inlet air temperature sensor trouble | Inspect (see chapter 3). |
Water temperature sensor trouble | Inspect (see chapter 3). |
Inlet air pressure sensor trouble | Inspect (see chapter 3). |
Fuel injector trouble | Inspect (see chapter 3). |
Run-on (dieseling): | |
Ignition switch trouble | Inspect and replace (see chapter 16). |
Engine stop switch trouble | Inspect and repair or replace (see chapter 2). |
Fuel injector trouble | Inspect (see chapter 3). |
Loose terminal of battery (-) cable or ECU ground lead | Inspect and repair (see chapter 16). |
Carbon accumulating on valve seating surface | Repair (see chapter 5). |
Engine overheating | (See Overheating) of Troubleshooting Guide, see chapter 17) |
Other: | |
Engine oil viscosity too high | Change (see chapter 2). |
Drive train trouble | Inspect drive chain (see chapter 2) and sprocket (see chapter 11). |
Brake dragging | Inspect caliper fluid seal damage or clogging of master cylinder relief and supply ports (see chapter 12). |
Clutch slipping | Inspect friction plates for wear (see chapter 6). |
Engine overheating | (See Overheating) of Troubleshooting Guide, see chapter 17) |
Air switching valve trouble | Inspect and replace (see chapter 5). |
Air suction valve trouble | Inspect and replace (see chapter 5). |
Intermittent any DFI fault and its recovery | Check that DFI connectors are clean and tight, and examine wires for signs of burning or fraying (see chapter 3). |