TOYOTA SUPRA 1986 Service Repair Manual

INSPECTION PROCEDURE
Remove AM2 fuse from R/B No.2.
Check continuity of AM2 fuse.
Continuity
Check voltage between terminals # 10 ~ 60 of engine control module and
body ground.
Check AM2 fuse.
(1) Connect SST (check harness ªAº).
See page EG±510)
SST 09990±01000
(2) Turn ignition switch ON.
Measure voltage between terminals # 10 ~ 60 of en-
gine control module and body ground.
Voltage: 9 Ð 14 V
Check for short in the harness and all the components
connected to AM2 fuse.
EG±584± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

(See page IN±30).
Disconnect solenoid resistor connector.
Measure resistance between terminals 1 and 2
~
4, 6 ~ 8 of solenoid resistor connector.
Resistance: Approx. 6
at 20°C (68°F)
Check resistance between terminals 1 and 2 ~ 4, 6 ~ 8 of solenoid resistor
connector.
Check for open in harness and connector between terminal E01, E02 of ECM
connector and body ground (See page IN±30).
Disconnect injector connector.
See page EG±273)
Measure resistance of injector.
Resistance: Approx. 1.95
at 20°C (68°F)
Check injection volume of injector.
(See page EG±279)

Injection volume
124
~ cm3/15 sec.
(7.6 Ð 8.8 cu in./15 sec.)
Difference between each injector:
Less than 10 cm
3 (0.6 cu in.)

Leakage
Fuel drop: One drop or less per minute
Replace solenoid resistor.
Check and repair harness and connector
between engine control module and battery.
Repair or replace harness or connector.
Replace injector.
Check and replace engine control module.
Check injectors.
Check and replace engine control module.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±585

CIRCUIT DESCRIPTION
The IAC valve is situated on the intake air chamber In-
take air bypassing the throttle valve is directed to the
IAC valve through a passage.
A step motor is built into the IAC valve. It consists of 4
coils, a magnetic rotor, valve shaft and a valve.
When the current flows to the coils due to signals from
the ECM, the rotor turns and moves the valve shaft for-
ward or backward, changing the clearance between
the valve and the valve seat.
In this way the intake air volume bypassing the throttle
valve is regulated, controlling the engine speed.
There are 125 possible positions to which the valve can
be opened.

With the engine idling measure wave forms
between terminals ISC1, ISC2, ISC3,
ISC4 and E01 of engine control module
when A/C switch ON or OFF.
HINT:
The correct waveforms are as shown.
INSPECTION USING OSCILLOSCOPEReference
IAC Valve Circuit
EG±586± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±587

INSPECTION PROCEDURE
(See page IN±30).
(See page EG±514).
Disconnect IAC valve connector.
Measure resistance between terminals shown be-
low.
Check IAC valve.
Check for open and short in harness and connector between EFI main relay
and IAC valve, IAC valve and engine control module (See page IN±30).
Repair or replace harness or connector.
Remove IAC Valve.
(1) Connect the battery positive lead to terminals
5 (B1) and 2 (B2), and the negative lead to ter±
minals 4(S1)Ð1(S2)Ð6(S3)Ð3(S4) in that or
der.
(2) Connect the battery positive lead to terminals
5 (B1) and 2 (B2) and the negative lead to ter±
minals 3(S4)Ð6(S3)Ð1(S2)Ð4(S1) in that or
der.
(1) The valve moves in the closing direction
(2) The valve moves in the opening direction.
Replace IAC valve.
Proceed to next circuit inspection shown on ma-
trix chart (See page EG±514).
TerminalResistance
EG±588± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

Turbo Control Circuit
CIRCUIT DESCRIPTION
[HINT]This turbocharger system has 3 control valves (Exhaust Bypass Valve, Exhaust Gas Control
Valve, Intake Air control Valve). Each valve is controlled by turbo pressure which is controlled
by VSV based on signals from ECM.
1.EXHAUST BYPASS VALVE
This valve controls the opening or closing of the exhaust bypass passage to ensure a smooth
transition from 1 turbo operation to 2 turbo operation.
2. EXHAUST GAS CONTROL VALVE
This valve controls the opening or closing of the No.2 exhaust passage in order to operate No.2
turbocharger.
3. INTAKE AIR CONTROL VALVE
This valve controls the opening or closing of the No.2 intake air passage in order to pass the
charged air from No.2 turbocharger.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±589

EG±590± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

INSPECTION PROCEDURE
(1) Remove VSV.
(2) Disconnect VSV connector.
(1) Measure resistance between terminals.
(2) Measure resistance between each terminal
and the body.
(1) Resistance: 22 Ð26
at 20°C (68°F)
(2) Resistance: 1 M
or higher
Check operation of VSV when battery positive volt-
age is applied and released to the VSV terminals.
Battery positive voltage is applied:
Air from port E is flowing out through port F.
Battery positive voltage is not applied:
Closed air passage from port E to F.
Check VSV for Exhaust Bypass Valve
Replace VSV for exhaust bypass valve.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±591

(1) Remove VSV.
(2) Disconnect VSV connector.
(1) Measure resistance between terminals.
(2) Measure resistance between each terminal
and the body.
(1) Resistance: 38 Ð 44
at 20°C (68°F)
(2) Resistance: 1 M
or higher
Check operation of VSV when battery positive volt-
age is applied and released to the VSV terminals.
Battery positive voltage is applied:
Air from port E is flowing out through port F.
Battery positive voltage is not applied:
Air from port E is flowing out through the air fil-
ter.
Check VSV for Exhaust Gas Control Valve
Replace VSV for exhaust gas control valve.
EG±592± ENGINE2JZ±GTE ENGINE TROUBLESHOOTING

(1) Remove VSV.
(2) Disconnect VSV connector.
(1) Measure resistance between terminals.
(2) Measure resistance between each terminal
and the body.
(1) Resistance: 38.5 Ð 44.5
at 20°C (68°F)
(2) Resistance: 1 M
or higher
Check operation of VSV when battery positive volt-
age is applied and released to the VSV terminals.
Battery positive voltage is applied:
Air from port E is flowing out through port F.
Battery positive voltage is not applied:
Air from port E is flowing out through the air
filter.
Check VSV for Intake Air Control Valve
Replace VSV for intake gas control valve.
± ENGINE2JZ±GTE ENGINE TROUBLESHOOTINGEG±593