ENGINE ELECTRICAL 6D – 21
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9. Through Bolt
1. Place a pilot bar into the through bolt hole to align the
front cover and the rear cover.
2. Install the through bolts and tighten them to the
specified torque.
Through Bolt Torque Nm (kgm/lbft)
3.1 3.9 (0.32 0.41 / 2.6 3.5)
11. Vaccum Pump
To install the generator -
1. Note the direction of the arrow on the vacuum pump.
2. Look forward from the base of the arrow to locate the
3 generator fixing points.
3. Twist the fixing points down and to the left to align
them with the middle of the center plate and the rotor.
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Install vanes into slits in rotor.
The vanes should be installed with the chamfered side
facing outward.
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Install the vacuum pump housing.
Make sure that the O-ring is not projecting beyond the
slots of the center plate.
Take care so that no scratching takes place on the vane
resulted by contact with the housing.
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Install the housing in the generator and fix it with the three
bolts.
Supply engine oil (5cc or so) from the oil port and check
that the generator pulley can be turned smoothly with your
hand.
Generator Housing Bolt Torque Nm (kgm/lbft)
5.9 6.9 (0.6 0.7 / 5.2 6.1)
ENGINE ELECTRICAL 6D – 27
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6. Use the circuit tester to check the armature for
continuity.
1 Hold the circuit tester probes against two
commutator segments.
2 Repear Step 1 at different segments of the
armature core.
There should be continuity between all segments of
the commutator.
If there is not, the armature must be replaced.
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YOKE
1. Use a circuit tester to check the field winding ground.
1 Hold one circuit tester probe against the field
winding end or brush.
2 Hold the other circuit tester probe against the bare
surface of the yoke body.
There should be no continuity.
If there is continuity, the field coil is grounded.
The yoke must be replaced.
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2. Use the circuit tester to check the field winding
continuity.
1 Hold one circuit tester probe against the “M”
terminal lead wire.
2 Hold the other circuit tester probe against the field
winding brush.
There should be continuity.
If there is no continuity, the yoke must be replaced.
6D – 32 ENGINE ELECTRICAL
MAGNETIC SWITCH
The following tests must be performed with the starter
motor fully assembled.
The yoke lead wire must be disconnected from the “M”
terminal.
To prevent coil burning, complete each test as quickly as
possible (within three to five seconds).
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Temporarily connect the solenoid switch between the
clutch and the housing and run the following test.
Complete each test within three to five seconds.
1. Pull-in Test
Connect the battery negative terminal with the solenoid
switch body and the M terminal. When current is applied to
the S terminal from the battery positive terminal, the pinion
should flutter.
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2. Hold-in Maintenance Test
Disconnect the lead at the M terminal. The pinion should
continue to flutter.
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3. Return Test
Disconnect the battery positive lead at the S terminal.
The pinion should return to its home position.
6E–66 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Throttle Position Sensor (TPS)
The TPS is a potentiometer connected to throttle shaft
on the throttle body. It is installed to the main TPS and
idle switch.
The engine control module (ECM) monitors the voltage
on the signal line and calculates throttle position. As the
throttle valve angle is changed when accelerator pedal
moved. The TPS signal also changed at a moved
throttle valve. As the throttle valve opens, the output
increases so that the output voltage should be high.
The engine control module (ECM) calculates fuel
delivery based on throttle valve angle.
Crankshaft Position (CKP) Sensor
The CKP sensor is located on top of the flywheel
housing of the flywheel and fix ed with a bolt.
The CKP sensor is of the magnet coil type. The
inductive pickup sensors four gaps in the flywheel
ex citer ring and is used to determine the engine speed
and engine cylinder top dead center (TDC). (1) Throttle Position Sensor (TPS)
(2) Idle Switch
1 2
Characteristic of TPS -Reference-
0 0.51 1.52 2.53 3.54 4.5
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Pedal Position (%) (Tech2 Readin
g
Output Voltage (V)
(1) Crankshaft Position (CKP) Sensor
(2) Fly wheel with sensor slot
1 2
4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–73
The pump camshaft speed sensor signal is utilized for
the following purposes.
To determine the momentary angular position of the
cam ring.
To calculate the actual speed of the fuel injection pump.
To determine the actual timing plunger position.
The pump camshaft sensor signal has a tooth gap, and
the crankshaft position (CKP) sensor on the flywheel
housing is used as a reference signal of engine top
dead center (TDC) for the start timing of fuel delivery or
injection which is to be set.High Pressure Solenoid Valve
Fuel injection quantity control is performed from the
beginning of pressure delivery at the beginning of cam
lift until the high pressure solenoid valve opens at the
end of pressure delivery.
This interval is called the pressure delivery interval.
Accordingly, the interval that the high pressure solenoid
valve is closed determines the fuel injection quantity
(high pressure fuel supply ends when the high pressure
solenoid valve opens).
-Cam Ring Angle
Sensor -Pump Speed
Wheel -Timer PositionPump
Control
Unit
(PSG)Pump
Camshaft
Speed
Sensor
(1) Valve Needle
(2) Magnet Anchor
(3) Coil
(4) High Pressure Passage
6E–74 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
When current from the pump control unit (PSG) flows to
the high pressure solenoid valve coil, the magnet
anchor (a movable iron core) pushes the valve needle,
toward the valve seat.
When the valve seat is completely closed by the valve
needle, the way, of the fuel in the high pressure
passage to the low pressure circuit is closed.
The pressure of the fuel in the high pressure passage is
rapidly increased by radial plunger lift, and the high
pressure fuel is delivered through the constant pressure
valve (CPV) to the nozzle holder assembly and is
injected into the engine cylinder.
When the fuel injection quantity demanded by the
engine is reached, the current to the coil is cut and the
valve needle re-opens the valve seat.
As a result of this, a path is opened for the fuel in the
high pressure passage to the low pressure circuit and
the pressure decreases. With a decrease in injection
pressure the nozzle closes and injection ends.Timing Control Valve (TCV)
The pressure of the fuel fed from the feed pump is
adjusted in accordance with speed by the regulating
valve. This delivery pressure acts on the hydraulic
stopper's annular chamber as control pressure.
The chamber pressure of the annular chamber is
controlled by the timing control valve (TCV).
The timing plunger is connected to the cam ring by a
ball pin. Ax ial movement of the timing plunger is
transferred to the cam ring in the form of rotational
movement. Movement to the right of the timing plunger
(to the spring side) advances injection timing. (1) Valve Needle
(2) Coil
(1) Cam Ring
(2) Servo Valve
(3) Timer Piston
(4) Outlet
(5) Feed Pump
(6) Inlet
(7) Fuel Suction
(8) Ball Pin
(9) Annular Chamber
(10) Hydraulic Stopper
(11) Return Passage
(12) Timing Control Valve (TCV)
4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–75
When control current flows to the timing control valve
(TCV) coil, the valve needle opens and the fuel annular
chamber flows through the orifice to the feed pump inlet.
Consequently, the pressure of the annular chamber
decreases and the hydraulic stopper is moved to the
retard side.
The timing control valve (TCV) acts as a variable
throttle, using the rapid opening and closing (cycling) of
the valve needle in the timing control valve (TCV).
At normal operation, the TCV controls the pressure
acting on the annular chamber so that the hydraulic
stopper cam move to any position, from the retard
position to the advance position. At this time, the duty
ratio is set by the pump control unit (PSG).
Duty ratio is the ratio of the time that the timing control
valve (TCV) is opened to one complete timing control
valve (TCV) operating cycle. A duty ratio change of
100% to 0% is an advance in injection timing. (The
VP44 displays an ON duty ratio.)The engine control module (ECM) contains
characteristic maps of the start of injection,
corresponding to engine operating conditions (engine
load, engine speed and engine coolant temperature).
The pump control unit (PSG) is constantly comparing
the set start of injection timing and the actual start of
injection timing. If there is a difference, the timing
control valve (TCV) is controlled by the duty ratio. (The
actual start of injection timing is determined from the
pump camshaft speed sensor.) (1) Coil
(2) From Annular Chamber
(3) To Feed Pump
(4) Orifice
(5) Valve Needle
Engine Load
Engine Speed
Engine Coolant
TemperatureEngine
Control
Module
(ECM)Pump
Control
Unit
(PSG)
Pump Camshaft
Speed Sensor
Timing
Control
Valve
(TCV)
4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–79
–Are there areas subjected to vibration or
movement (engine, transmission or
suspension)?
–Are there areas ex posed to moisture, road salt
or other corrosives (battery acid, oil or other
fluids)?
–Are there common mounting areas with other
systems/components?
–Have previous repairs been performed to wiring,
connectors, components or mounting areas
(causing pinched wires between panels and
drivetrain or suspension components without
causing and immediate problem)?
–Does the vehicle have aftermarket or dealer-
installed equipment (radios, telephone, etc.)
Step 2: Isolate the problem
At this point, you should have a good idea of what could
cause the present condition, as well as could not cause
the condition. Actions to take include the following:
Divide (and separate, where possible) the system or
circuit into smaller sections
Confine the problem to a smaller area of the vehicle
(start with main harness connections while removing
panels and trim as necessary in order to eliminate
large vehicle sections from further investigation)
For two or more circuits that do not share a common
power or ground, concentrate on areas where
harnesses are routed together or connectors are
shared (refer to the following hints)
Hints
Though the symptoms may vary, basic electrical failures
are generally caused by:
Loose connections:
–Open/high resistance in terminals, splices,
connectors or grounds
Incorrect connector/harness routing (usually in new
vehicles or after a repair has been made):
–Open/high resistance in terminals, splices,
connectors of grounds
Corrosion and wire damage:
–Open/high resistance in terminals, splices,
connectors of grounds
Component failure:
–Opens/short and high resistance in relays,
modules, switches or loads
Aftermarket equipment affecting normal operation of
other systems
You may isolate circuits by:
Unplugging connectors or removing a fuse to
separate one part of the circuit from another part
Operating shared circuits and eliminating those that
function normally from the suspect circuit
If only one component fails to operate, begin testingat the component
If a number of components do no operate, begin tests
at the area of commonality (such as power sources,
ground circuits, switches or major connectors)
What resources you should use
Whenever appropriate, you should use the following
resources to assist in the diagnostic process:
Service manual
Technical equipment (for data analysis)
Ex perience
Technical Assistance
Circuit testing tools
5d. Intermittent Diagnosis
By definition, an intermittent problem is one that does
not occur continuously and will occur when certain
conditions are met. All these conditions, however, may
not be obvious or currently known. Generally,
intermittents are caused by:
Faulty electrical connections and wiring
Malfunctioning components (such as sticking relays,
solenoids, etc.)
EMI/RFI (Electromagnetic/radio frequency
interference)
Aftermarket equipment
Intermittent diagnosis requires careful analysis of
suspected systems to help prevent replacing good
parts. This may involve using creativity and ingenuity to
interpret customer complaints and simulating all
ex ternal and internal system conditions to duplicate the
problem.
What you should do
Step 1: A cquire information
A thorough and comprehensive customer check sheet
is critical to intermittent problem diagnosis. You should
require this, since it will dictate the diagnostic starting
point. The vehicle service history file is another
source for accumulating information about the
complaint.
Step 2: A nalyze the intermittent problem
Analyze the customer check sheet and service history
file to determine conditions relevant to the suspect
system(s).
Using service manual information, you must identify,
trace and locate all electrical circuits related to the
malfunctioning system(s). If there is more than one
system failure, you should identify, trace and locate
areas of commonality shared by the suspect circuits.