Fuel Temperature Sensor; Fuel Volume Regulator - Yanmar BY Series Service Manual

ELECTRICAL AND ECU
Figure 12-15
Figure 12-15
1 – Pin 1 - Glow plug No. 1
2 – Pin 2 - Glow plug No. 2
3 – Pin 3 - Glow plug No. 3
4 – Pin 4 - Glow plug No. 4
5 – Pin 5 - Glow plug No. 5
6 – Pin 6 - Glow plug No. 6
7 – Pin 12 - Signal of measured value
(ECU pin 168)
8 – Pin 6 - Ground (ECU pin 170)
9 – Pin 5 - 12V (Fuse F5)
Connector X3
The control signals travel via connector X3. If the
glow control unit is not installed, connector X3 must
be protected by a cover.

Fuel Temperature Sensor

This sensor measures the temperature of the fuel
being supplied to the high-pressure fuel pump. It is
an NTC (negative temperature coefficient) type
sensor. It is mounted in the fuel line just upstream
from the high-pressure fuel pump.
The sensor output is used by the ECU for:
• Protecting the engine from overheating
• Calculation of the injection rate
• Calculation of the rate of the fuel pump
Results of Failed Sensor
Failure of the sensor results in:
• Limitation of the injection rate (See Engine Faults
and Torque Limitations on page 13-3.)
• Destruction of the sensor if short circuit to B+
If this sensor is defective, the following P-codes
may be generated:
• P0182 - short circuit to B+
12-18
0004172
© 2009 Yanmar Marine International
• P0183 - No connection / short to ground
Test Values
• Resistance at -20°C (-4°F): 20 to 24 k-ohm
• Resistance at 0°C (32°F): 16.5 to 8 k-ohm
• Resistance at 20°C (68°F): 2.4 to 3.2 k-ohm
• Resistance at 120°C (248°F): 0.5 to 0.6 k-ohm
Figure 12-16
(1)
Figure 12-16
1 – Pin 1 - Ground (ECU pin 111)
2 – Pin 2 - Out (ECU pin 183)

Fuel Volume Regulator

This component controls fuel volume in the fuel
injection system. The ECU uses values supplied by
several sensors and sends corresponding signals
to control fuel pressure. It is mounted on the rear of
the high-pressure fuel pump.
Results of Failed Regulator
Failure of the regulator results in:
• Limitation of the injection rate (See Engine Faults
and Torque Limitations on page 13-3.)
• All high-pressure fuel system control is provided
by the fuel rail pressure control valve.
NOTICE: If a fault code is generated, check the
fuel supply and delivery first.
If this regulator is defective, the following P-codes
may be generated:
• P0001 - not connected
• P0003 - short circuit to ground
• P0004 - short circuit to B+
• P0088 - fuel rail pressure out of range
BY Service Manual
Component Tests
(2)
0004168