KS Motorcycles K-LIGHT125, Maintenance Manual

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b) Disconnect the fuel pump connector and check whether the fuel pump supply voltage is around 12V.
c) If there is no problem in step b, the external battery is connected to supply 12V DC power to the fuel
pump to check whether the fuel pump is running.
d) If the fuel pump is running normally, use a gasoline pressure gauge to check whether the fuel tube
pressure at the front end of the injector is about 300Kpa when the engine is in idling state.
e) If the pipeline pressure is lower than 270Kpa, check whether there is leakage in the oil line, whether the
fuel pump is rotating in the reverse direction, and whether the filter is blocked.
18.2.10.4 Common Problems
a) The fuel pump assembly plug-in is reversed, which enables the fuel pump to reverse and fail to provide
the engine with sufficient fuel pressure, resulting in engine failure.
b) The fuel pump is damaged and fails to rotate.
Precautions:
1) Because there is no gasoline in the fuel tank of new motorcycle at the beginning, a lot of air is generated
at fuel pipe, so it needs to start it for several times to empty the air in the fuel line, and then the engine
can work properly, which is normal. Motorcycle will be started easily in the future.
2) Because gasoline can cool fuel pump, do not let fuel pump work little oil or no gasoline, which may
burn fuel pump.
18.2.10.5 Fault Determination:
1. Inspection of fuel pump: Measure the voltage between pin 1 and pin 2 of fuel pump with a multimeter;
Standard: Within 3S after the ignition key is inserted or during the start-up process: 12±2V.
2. Inspection of fuel pump circuit:
Fuel pump 1—ECU2 Standard: On
NG: Control-Open circuit
Fuel pump 2—ECU9 Standard: On
NG: Open circuit
Fuel pump 2—To ground Standard: Off
NG: Power+ Short circuit
18.3 Fault Maintenance and Diagnosis Method
The fault light is located on the meter panel with a FI mark below. Under normal circumstances, after the key
is turned, if the engine in the neutral position, and the fault light is on, it indicates that the electronic injection
system is powered and it can work; if the fault light is off, it indicates that the electronic injection system circuit is
disconnected, it will not work and the connection of positive and negative electrodes of fuse and battery should be
checked. If the fault light is off after the engine is started, it indicates that there is no fault; on the contrary, if the
fault light is still on after the engine is started, it indicates that the electronic injection system works abnormally
and the fault should be removed if any.
Table of fault code
Component
Fault
Code
Monitor Strategy Fault detection criteria
MI activation
Criteria
Chinese
description
Throttle
Position Sensor
P0123
Signal range check high for
throttle Position Sensor
Voltage of throttle position
sensor is higher than 4.9V.
1st cycle
Throttle position
sensor is
short-circuited to
power
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