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FUEL SYSTEM / FUEL INJECTION
4.19
TROUBLESHOOTING
FUEL STARVATION/LEAN MIXTURE
Symptoms: Hard start or no start, bog, backfire,
popping through intake / exhaust, hesitation,
detonation, low power, spark plug erosion, engine
runs hot, surging, high idle, idle speed erratic.
G No fuel in tank
G Restricted tank vent, or routed
improperly
G Fuel lines or fuel injectors restricted
G Fuel filter plugged
G Fuel pump inoperative
G Air leak in system
G Intake air leak (throttle shaft, intake
ducts, airbox or air cleaner cover)
G Incorrect throttle stop screw
adjustment
RICH MIXTURE
Symptoms: Fouls spark plugs, black, sooty exhaust
smoke, rough idle, poor fuel economy, engine runs
rough/ misses, poor performance, bog, engine loads
up, backfire.
G Air intake restricted (inspect intake
duct)
G Air filter dirty/plugged
G Poor fuel quality (old fuel)
G Fouled spark plug
G TPS setting incorrect
G Injector failure
POOR IDLE
Idle Too High (If greater than 1300 RPM when
engine is warm)
G Throttle stop screw set incorrect
G Throttle cable sticking, improperly
adjusted, routed incorrectly
Idle Too Low (If less than 900 RPM when engine
is warm)
G Plugged air filter
G Leaking injector (rich condition)
G Belt dragging
G Throttle stop screw set incorrect
Erratic Idle
G Throttle cable incorrectly adjusted
G Air leaks, dirty injector
G TPS damaged or adjusted
incorrectly
G Tight valves
G Ignition timing incorrect
G Belt dragging
G Dirty air cleaner
G Engine worn
G Spark plug fouled
G Throttle stop screw set incorrectly
(out of sync with ECU)