Fault Phenomenon-Extremely High Fuel Consumption - Benelli TNT125 Maintenance Manual

Fault phenomenon—Extremely high fuel consumption
a) Check whether the oxygen sensors of two
cylinders are assembled in place; if it is in the
loose state, the oxygen sensor may incorrectly
judge that the combustion in the cylinder is thin,
and then increase fuel, which may result in
unusually high fuel consumption.
b) After confirming that the engine mechanical parts
and oxygen sensor are in normal conditions, run
the engine to observe the oxygen sensor reading. If
the reading is always greater than 500 mV at
normal water temperature, check whether there is
leakage in fuel injector.
Notes
The vast majority of EFI parts cannot be repaired;

after the confirmation of damaged parts, generally
replacement is taken.
When starting the engine, do not operate any

mechanism (including the throttle, do not pull the
throttle for start) on the engine.
If engine fault lamp becomes on during the engine

operation, cause must be checked and eliminated
as soon as possible.
Do not use leaded gasoline, because lead may

damage the oxygen sensor and three-way catalytic
converter.
If oil consumption is abnormal, the problem

should be resolved as soon as possible, because
some of the substances in the oil may damage the
oxygen sensor and three-way catalytic converter.
Valve clearance should not be too small, if the

exhaust valve is not shut off tightly, exhaust
temperature may become too high and thus
shorten the life of three-way catalytic converter.
At the temperature of below 10°C, if the vehicle

and engine run at low speed for a long time, the
exhaust pipe may have carbon deposition and
become black, which is a normal phenomenon. It
will be eliminated after a period of high-speed
operation, or appropriate means should be taken to
keep the engine coolant temperature within the
specified temperature range.
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