9
SERVICE TECH Vol.465 03-4
This session describes the construction and operation of the ECD-V3 pump with respect to the pumping and injection of fuel.
• Solenoid Spill Valve (SPV) - - - - - - - - - - - - - - This actuator, which performs the function of the spill ring of the
previous distributor type pump, controls the injection quantity.
• NE Sensor (NE) - - - - - - - - - - - - - - - - - - - - - - This sensor, which detects the camshaft position of the pump,
also inputs the number of revolutions of the pump (one-half the
number of revolutions of the engine) to the engine ECU.
• Fuel Temperature Sensor (THF) - - - - - - - - - - This sensor detects the temperature of the fuel.
• Correction Resistor or ROM - - - - - - - - - - - - -
This part makes corrections to the injection quantity and injection timing.
• Timing Control Valve (TCV)- - - - - - - - - - - - - - This actuator, which performs the function of the timer of the
previous distributor type pump, controls the injection timing.
1
1
Composition and Construction of ECD-V3 Pump System
Feed
Pump
Fuel Filter
Fuel Temperature
Sensor
NE Sensor
Overflow
Valve
Solenoid Spill
Valve
Nozzle
Pressure Chamber
Delivery Valve
Timing Control Valve
Plunger

Fuel Tank
Sensor Signal
(NE Signal)
Solenoid Spill Valve Actuation Signal
Intake
Temperature
Sensor
Throttle
Coolant
Temperature
Sensor
Intake
Pressure Sensor
Crankshaft
Position
Sensor
Accelerator
Position
Sensor
Sensor Signal
Crankshaft
Position Sensor
Sensor Position
Engine

ECU
Timing Control Valve
(TCV)
Timer Piston
Solenoid Spill Valve (SPV)

Pressure Chamber
Delivery Pump
Plunger
Cam Plate
Regulating Valve
NE Sensor (NE)
Fuel Temperature Sensor (THF)
10
SERVICE TECH Vol.465 03-4
The mechanism for the suction and pumping/distribution of the fuel is basically the same as for the previous
distributor type pump. However, it differs in the aspect that it controls the fuel injection
quantity
by opening and
closing a solenoid spill valve by way of electric signals. The solenoid spill valve is provided in the passage that
links the pump chamber with the pressure chamber.
As the plunger descends, it draws fuel from the suction port into the pressure chamber. At this time, the solenoid
spill valve is energized and closed.
The plunger ascends while rotating, in order to pressurize and pump the fuel in the pressure chamber.
When the solenoid spill valve is no longer energized, the spill valve opens. Then, the high-pressure fuel in the
pressure chamber spills into the pump chamber, thus reducing its pressure and ending the injection of fuel.
Suction Port : open
Distribution Port : closed
Solenoid Spill Valve: closed
Suction Port : closed
Distribution Port : open
Solenoid Spill Valve: closed
Suction Port : closed
Distribution Port : open
Solenoid Spill Valve: open
2

2
Operation of ECD-V3 Pump
2-1 Fuel Suction and Injection
Suction Stroke
Solenoid Spill Valve
(closed)
Speed Sensor
Plunger Distribution Port (closed)
Suction Port (open)
to Nozzle
Cam Plate
Roller Ring
Pulsar
Drive Shaft
Pressure Chamber
Pump Chamber
Pumping Stroke (Injection)
Solenoid Spill Valve
(closed)
Distribution Port (open)
Suction Port (closed)
End of Injection
Solenoid Spill Valve
(open)
Suction Port (closed)
Distribution Port (open)
SERVICE TECH Vol.465 03-4
11
The solenoid spill valve, which is located in the passage that links the pump chamber of the injection pump with the
pressure chamber, is a type of solenoid valve that turns ON/OFF (opens and closes) in accordance with the signals

from the engine ECU.
When the coil of the solenoid spill valve is energized, the spill valve closes, thus closing the passage that links the
pressure chamber with the pump chamber. As a result, the plunger pressurizes the fuel in the pressure chamber and
pumps it into the nozzles through which the fuel is injected.
When the solenoid spill valve is no longer energized, the spill valve opens, thus opening the passage between the
pressure chamber and pump chamber. The pressurized fuel spills into the pump chamber, thus decreasing the
pressure in the pressure chamber and ending the pumping of fuel.
The solenoid spill valve is directly related to the control of the fuel injection volume. Therefore, it must provide high
levels of precision, quick response, and pressure resistance, as well as a large spill volume.
There are two types of solenoid spill valves: the pilot valve type, and the direct-acting solenoid valve type. The
direct-acting solenoid valve type is widely used today.
The pumps are classified into the ECD-V3, ECD-V3 (ROM), and ECD-V3 direct-acting valve types, depending on
the type of solenoid spill valve and the injection volume correction method that are being used.
Coil energized ........ valve closed
(during suction or injection)
Coil non-energized . valve open
(end of injection)
Type Characteristic
Correction
Method
Solenoid Spill Valve (SPV)
ECD-V3
An externally mounted correction
resistor is able to correct the final
injection
quantity
.
Correction
Resistor
ECD-V3

(ROM)
The data of an externally mounted
ROM is used to correct the final injection
quantity
. It realizes a higher precision
level of correction than the previous type
(correction resistor).
ROM
ECD-V3
Direct-Acting Valve

Types
A direct-acting SPV is used to achieve
high levels of response and spill
performance.
ROM
3
3
Solenoid Spill Valve (SPV)
Solenoid Spill Valve
Plunger
Pressure
Chamber
Coil
to Nozzle
Pump Chamber
Valve
3-1 Types of Solenoid Spill Valves
Pilot Valve Type
Direct-Acting Type

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SERVICE TECH Vol.465 03-4
This solenoid spill valve provides a quick response at a higher level of precision. It consists of a spool valve and
a solenoid coil. The spool valve, which acts directly in accordance with electric signals, opens and closes the
passage that links the pressure chamber and the pump chamber.
This type consists of a main valve, pilot valve, and a solenoid coil. When the solenoid coil is energized, it pulls on
the pilot valve (downward in the diagram), thus closing the pilot spill port.
At this time, the high-pressure fuel, which flowed in from the pressure chamber via the restriction, fills the main
valve. The resulting hydraulic pressure firmly closes the main valve.
When the solenoid coil is no longer energized, the pilot valve opens, allowing the fuel in the main valve to spill
through the pilot spill port. Thus, the pressure in the main valve decreases suddenly. This pressure difference
causes the main valve to open considerably, effectively ending the injection of fuel.
Pilot Valve Type
Solenoid Spill Valve
Coil
Pilot Valve
Main Valve
Pressure Chamber
Plunger
Main Spring
Control Spring
Pilot Spring
Pilot Valve Type
Direct-Acting Solenoid Valve Type
Spool Valve
Spring Armature
CoilCore
Coil
Spring
Valve Body

Valve Body
Spool Valve
Cross Section View
Enlargement View