Sym Fiddle III 50 Service Manual page 128

SYM
Engine temperature Sensor Illustration:
ET SENSOR
O
ACG/FLY
WHEEL
CPS
Basic Principle
Cylinder head temperature sensor is an NTC thermistor chip, its resistance changes with temperature
changes, so can the acquisition cylinder head temperature in real time.
Function description:
Use of ECU provide DC 5 v power supply, a total of two pin plug, 1 branch voltage output pin; 1 for the
●
grounding pin.
Its main composition is a negative temperature coefficient thermistor (smaller temperature rise of
●
resistance).
Device in the cylinder head, along with the engine temperature sensor resistance, with the induction to
●
the temperature change, and converted into a voltage signal is sent to the ECU to calculate the time of
the engine temperature, ECU again in accordance with the state of engine warming-up correction repair
time and ignition Angle.
Testing Procedures:
Resistance measurement:
●
Remove the engine temperature sensor.
●
Use "Multi-meter" ohms range, inspect the sensor resistance.
●
Detection judge:
The relationship between Resistance value and temperature：
Temperature(℃) Resistance value(KΩ)
-20
969.8±48.5
20
127.6±6.375
40
54.9±2.745
80
13.01±0.65
Treatment of abnormal phenomena:
The engine temperature sensor is damage, or adapter connector poor contact.
●
Check whether there is any abnormal on main distribution line.
●
When the engine temperature sensor is abnormal, suggestion is to replace new engine temperature
●
sensor.
4
. ELECTRONICALLY CONTROLLED CARBURETOR SYSTEM
TPS
SENSOR
2
ECU
BATTERY
IGN COIL
PLUG
4-9