Page 97 of 192
COMPONENT INSPECTION
Adjustment resistor
Check resistance between terminalsV2andV6.
Resistance: Approximately 0.2 - 15.0 kW[at 25ÉC
(77ÉF)]
Resistance value varies with adjustment sensor num-
bers.
If NG, replace adjustment resistor.
Always replace adjustment resistor with a new one which has same
number on label.
SEF683V
TROUBLE DIAGNOSIS FOR ``ADJUST RESISTOR'' (DTC 17)
Adjustment Resistor (Cont'd)
EC-95
Page 98 of 192

Electric Governor
The electric governor is built into the electronic fuel injection pump.
It moves the control sleeve to increase or decrease the amount of
fuel injected.
When current ¯ows through the coil, a magnetic force is produced,
rotating the rotor. The rotor shaft is installed to the control sleeve
via a ball pin which is eccentrically situated in relation to the rotor
shaft. With this arrangement, the control sleeve can be moved in
relation to rotor rotation.
The rotor's rotating angle is determined by a balanced condition of
magnetic force (generated by current ¯ow regulated by means of
the ECM) and tension of return spring (installed to rotor). The larger
the current ¯ow through the coil, the greater the rotor's rotating
angle. This means that the control sleeve moves to the right,
increasing the amount of fuel injected.
The ECM regulates the current ¯ow through the coil by changing
the duty ratio which controls the ON-OFF operation of the electric
governor grounding circuit.
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
4 B/Y ECCS relay (Self-shutoff)Ignition switch ``ON''
Ignition switch ``OFF''
For a few seconds after turning ignition switch
``OFF''0 - 1.5V
Ignition switch ``OFF''
A few seconds passed after turning ignition
switch ``OFF''BATTERY VOLTAGE
(11 - 14V)
101
107R/B Electric governorEngine is running.
Idle speedBATTERY VOLTAGE
(11 - 14V)
SEF632S
SEF633S
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
EC-96
Page 99 of 192
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
102
108G/Y Electric governor groundEngine is running.
Idle speedApproximately 10V
SEF727V
Engine is running.
Engine speed is 2,000 rpm.Approximately 10V
SEF728V
11 6
11 7W Power supply for ECM Ignition switch ``ON''BATTERY VOLTAGE
(11 - 14V)
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Items
(Possible cause)
18, 22, 25+Fuel injection feedback system does not operate prop-
erly. (This system consists essentially of ECM, electric
governor and control sleeve position sensor.)+Main power supply circuit (ECM terminals
11 6,11 7)
and fuse
+Harness or connectors
(Electric governor and control sleeve position sensor
circuit)
+Electric governor
+Electronic fuel injection pump
+ECM
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
Electric Governor (Cont'd)
EC-97
Page 100 of 192

DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
Note: If DTC 18, 22, 25 and DTC 15 are displayed, perform
TROUBLE DIAGNOSIS FOR DTC 15. (See EC-87.)
1) Turn ignition switch ``ON'' and select ``DATA MONITOR''
mode with CONSULT.
2) Start engine and warm it up to normal operating tem-
perature.
3) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Start engine and warm it up to normal operating tem-
perature.
2) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
3) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
4) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
Note: If a malfunction occurs intermittently, conduct suitable
driving pattern for 10 minutes. This makes it possible to
determine DTC.SEF751V
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
Electric Governor (Cont'd)
EC-98
Page 101 of 192
TEC429
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
Electric Governor (Cont'd)
EC-99
Page 102 of 192

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
Refer to EC-63.
CHECK POWER SUPPLY CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect ECM harness connector
and electronic fuel injection pump har-
ness connector.
3. Check harness continuity between ter-
minal
V1and ECM terminals101,107.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK GROUND CIRCUIT.
Check harness continuity between termi-
nal
V5and ECM terminals102,108.
Continuity should exist.
If OK, check harness for short to ground
and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK COMPONENT
(Electric governor).
Refer to ``COMPONENT INSPECTION''
below.
OK
cNG
Take proper action.
Disconnect and reconnect harness connec-
tors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness con-
nector. Reconnect ECM harness connector
and retest.
INSPECTION END
COMPONENT INSPECTION
Electric governor
1. Disconnect electronic fuel injection pump harness connector.
2. Check continuity between terminals
V1andV5.
Resistance: Approximately 0.68W[at 23ÉC (73ÉF)]
If NG, take proper action.
SEF679VA
SEF752V
SEF753V
SEF684V
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``F/INJ F/B 2'' (DTC 18),
``F/INJ F/B'' (DTC 22), ``ELECTRIC GOV'' (DTC 25)
Electric Governor (Cont'd)
EC-100
Page 103 of 192

Injection Timing Control Valve
The injection timing control valve is built into the electronic fuel
injection pump. It controls the timer piston to change the fuel injec-
tion timing.
The timing control valve is a solenoid valve located in the line
between high-pressure chamber and low-pressure chamber. It
changes fuel pressure in the high-pressure chamber.
When current ¯ows through the solenoid (the solenoid turns ON),
the timing control valve opens, advancing fuel injection timing.
When current does not ¯ow through it, the timing control valve
closes, retarding injection timing.
The ECM emits an ON-OFF duty signal. The longer the OFF-
duration, the greater the advance angle. The longer the
ON-duration, the greater the retard angle. This means that chang-
ing the ON-OFF duty ratio makes it possible to achieve an optimal
advance angle and accurately control fuel injection timing.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Speci®cation data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
ACT INJ TIMG+Engine: After warming up
+Air conditioner switch: ``OFF''
+Shift lever: ``N''
+No-loadIdle þ9.5 to þ12.0É
2,000 rpm þ10.0 to þ15.5É
INJ TIMG C/V+Engine: After warming up, idle the engine. Approx. 50%
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC Voltage and Pulse
Signal)
104
11 0L/WInjection timing control
valveEngine is running.
(Warm-up condition)
Idle speedBATTERY VOLTAGE
(11 - 14V)
SEF729V
Engine is running.(Warm-up condition)
Engine speed is 2,000 rpm.BATTERY VOLTAGE
(11 - 14V)
SEF730V
SEF638S
TROUBLE DIAGNOSIS FOR ``F/INJ TIMG F/B'' (DTC 21)
EC-101
Page 104 of 192

ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble Code
No.Malfunction is detected when ....Check Items
(Possible cause)
21+Injection timing feedback system does not operate
properly. (This system consists essentially of ECM,
injection timing control valve and needle lift sensor.)+Harness or connectors
[Injection timing control valve, needle lift sensor,
crankshaft position sensor (TDC) circuits]
+Injection timing control valve
+Needle lift sensor
+Crankshaft position sensor (TDC)
+Air in fuel line
DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
Note: If both DTC 21 and 34 or 47 are displayed, perform
TROUBLE DIAGNOSIS FOR DTC 34 or 47. (See EC-126
or EC-144.)
1) Turn ignition switch ``ON'' and select ``DATA MONITOR''
mode with CONSULT.
2) Start engine and warm it up to normal operating tem-
perature.
3) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Start engine and warm it up to normal operating tem-
perature.
2) Run engine for 2 seconds at 3,000 rpm. Return engine
speed to idle, then increase to 3,000 rpm under no load.
3) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
4) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
Note: If a malfunction occurs intermittently, conduct suitable
driving pattern for 10 minutes. This makes it possible to
determine DTC.
SEF751V
TROUBLE DIAGNOSIS FOR ``F/INJ TIMG F/B'' (DTC 21)
Injection Timing Control Valve (Cont'd)
EC-102