TOYOTA SUPRA 1995 Service Repair Manual

THROTTLE BODY REMOVAL
Installation is in the reverse order of removal.
1. DRAIN ENGINE COOLANT
2. REMOVE THROTTLE BODY
(a) Disconnect the hose, cables and connectors from the throttle
body:
(1) Air hose
(2) Accelerator cable
(3) Cruise control actuator cable
(4) Throttle position sensor connector
(5) Sub±throttle position sensor connector
(6) Sub±throttle actuator connector
(b) Remove the 2 bolts and 2 nuts, and disconnect the throttle
body from the air intake chamber.
Torque: 21 NVm (210 kgfVcm, 15 ftVlbf)
(c) Remove the gasket.
INSTALLATION HINT: Use a new gasket.
(d) Disconnect these hoses from the throttle body, and remove
the throttle body:
(1) EVAP hose
(2) Water bypass hose (from No.4 water bypass pipe)
(3) Water bypass hose (from cylinder head)
(4) PS air hose
THROTTLE BODY INSPECTION
Throttle Body
1. CLEAN THROTTLE BODY
(a) Using a soft brush and carburetor cleaner, clean the cast
parts.
(b) Using compressed air, clean all the passages and apertures.
NOTICE: To prevent deterioration, do not clean the throttle
position sensors, actuator, dashpot and throttle opener.
2. INSPECT THROTTLE VALVE
(a) Disconnect the throttle opener vacuum hose from the throttle
body.
(b) Apply vacuum to the throttle opener.
(c) Check that there is no clearance between the throttle stop
screw and throttle lever when the throttle valve is fully closed.
(d) Reconnect the vacuum hose to the throttle body.
± ENGINESFI SYSTEM (2JZ±GTE)EG±291

Throttle Position Sensor
1. INSPECT THROTTLE POSITION SENSOR
(a) Disconnect the throttle opener vacuum hose from the throttle
body.
(b) Apply vacuum to the throttle opener.
(c) Insert a 0.54 mm (0.021 in.) or 0.70 mm (0.028 in.) feeler
gauge between the throttle stop screw and stop lever.
(d) Using an ohmmeter, measure the resistance between each
terminal.
 
 
Clearance between
lever and stop screw 
 Between terminals 
 Resistance
 0 mm (0 in.) VTA±E2 0.34±6.3

 0.54 mm (0.021 in.) IDL±E2 0.5 k
or less 0.70 mm (0.028 in.) IDL±E2 Infinity 
 
 
Throttle valve fully
Open
 
 
 
VTA±E2
 
 
 
2.4±11.2 k

 ± VC±E2 3.1±7.2 k

2. IF NECESSARY, ADJUST THROTTLE POSITION
SENSOR
(a) Loosen the 2 set screws of the sensor.
(b) Insert a 0.65 mm (0.026 in.) feeler gauge between the throttle
stop screw and stop lever.
(c) Connect the tester probe of an ohmmeter to the terminals IDL
and E2 of the sensor. EG±292
± ENGINESFI SYSTEM (2JZ±GTE)

(d) Gradually turn the sensor clockwise until the ohmmeter
deflects, and secure it with the 2 set screws.
(e) Recheck the continuity between terminals IDL and E2.
 
 
Clearance between
lever and stop screw 
 Continuity (IDL±E2)
 0.54 mm (0.021 in.) Continuity
 0.70 mm (0.028 in.) No continuity
(f) Reconnect the vacuum hose to the throttle body.
Sub±Throttle Actuator, Sub±Throttle
Valve and Throttle Position Sensor
1. INSPECT SUB±THROTTLE ACTUATOR
Using an ohmmeter, measure the resistance between the ter-
minals (ACM to A and A±, BCM to B and B±).
Resistance:
0.82±0.98
at 20°C (68°F)
If the resistance is not as specified, replace the actuator.
2. REMOVE SUB±THROTTLE ACTUATOR
Remove the 4 screws and sub±throttle actuator.
± ENGINESFI SYSTEM (2JZ±GTE)EG±293

3. INSPECT SUB±THROTTLE VALVE
Check that there is no clearance between the throttle stop
screw and throttle valve gear when the subthrottle valve is ful-
ly closed.
4. INSPECT SUB±THROTTLE POSITION SENSOR
(a) Set the sub±throttle valve to fully closed position.
(b) Insert a 0.41 mm (0.016 in.) or 0.48 mm (0.019 in.) feeler
gauge between the throttle stop screw and throttle valve
gear.
(c) Using an ohmmeter, measure the resistance between
terminals.
 
 Clearance between
lever and stop screw 
 Between terminals
 
 Resistance
 0 mm (0 in.) VTA±E2 0.3±6.3 k
 0.41 mm (0.016 in.) IDL±E2 0.5 k
or less 0.48 mm (0.019 in.) IDL±E2 Infinity 
 Throttle valve fully
open 
 VTA±E2
 
 2.0±10.8 k

 ± VC±E2 3.5±6.5 k

5. IF NECESSARY, ADJUST SUB±THROTTLE POSITION
SENSOR
(a) Loosen the 2 set screws of the sensor.
(b) Set the sub±throttle valve to fully closed position.
(c) Insert a 0.45 mm (0.018 in.) feeler gauge, between the
throttle stop screw and throttle valve gear. EG±294
± ENGINESFI SYSTEM (2JZ±GTE)

(d) Connect the tester probe of an ohmmeter to the terminals IDL
and E2 of the sensor.
(e) Gradually turn the sensor clockwise until the ohmmeter
deflects, and secure it with the 2 set screws.
(f) Recheck the continuity between terminals IDL and E2.
 
 
Clearance between
lever and stop screw 
 Continuity (IDL±E2)
 0.41 mm (0.016 in.) Continuity
 0.48 mm (0.019 in.) No continuity
6. REINSTALL SUB±THROTTLE ACTUATOR
Install the sub±throttle actuator with the 4 screws.
± ENGINESFI SYSTEM (2JZ±GTE)EG±295

IDLE AIR CONTROL (IAC) VALVE
ON±VEHICLE INSPECTION
1. INSPECT IAC VALVE FOR OPERATING SOUND
Check that there is a clicking sound immediately after stop-
ping the engine.
If operation is not as specified, check the IAC valve, wiring
and ECM.
2. INSPECT IAC VALVE RESISTANCE
Using an ohmmeter, measure the resistance between the ter-
minals (B1 (or B2) to others).
Resistance:
At 20°C (68°F) 18±24

If resistance is not as specified, replace the IAC valve.
COMPONENTS FOR REMOVAL AND
INSTALLATION
EG±296± ENGINESFI SYSTEM (2JZ±GTE)

IAC VALVE REMOVAL
1. DRAIN ENGINE COOLANT
2. DISCONNECT IAC VAVE CONNECTOR
3. REMOVE IAC VALVE
(a) Remove the 2 bolts, and disconnect the IAC valve from the
air intake chamber.
(b) Remove the gasket.
(c) Disconnect these hoses from the IAC valve, and remove the
IAC valve:
(1) Air hose
(2) Water bypass hose (from No.2 water bypass pipe)
(3) Water bypass hose (from No.4 water bypass pipe)
(d) Remove the seal washer and check valve.
IAC VALVE INSPECTION
INSPECT IAC VALVE OPERATION
(a) Apply battery voltage to terminals B1 and B2, and while
repeatedly grounding S1±S2±S3±S4±S 1 in sequence, and
check that the valve moves toward the closed position.
(b) Apply battery voltage to terminals B1 and B2, and while
repeatedly grounding S4±S3±S2±S1±S 4 in sequence,
check that the valve moves toward the open position.
If operation is not as specified, replace the IAC valve.
± ENGINESFI SYSTEM (2JZ±GTE)EG±297

IAC VALVE INSTALLATION
1. INSTALL IAC VALVE
(a) Install the check valve and seal washer.
NOTICE: Be careful of the check valve and seal washer instal-
lation direction.
(b) Connect these hoses:
wAir hose
wWater bypass hose (from No.2 water bypass pipe)
wWater bypass hose (from No.4 water bypass pipe)
(c) Install a new gasket and the IAC valve with the 2 bolts.
Torque: 21 NVm (210 kgfVcm, 15 ftVlbf)
2. CONNECT IAC VALVE CONNECTOR
3. FILL WITH ENGINE COOLANT
EFI MAIN RELAY
EFI MAIN RELAY INSPECTION
1. REMOVE EFI MAIN RELAY
LOCATION: In the engine compartment relay box.
2. INSPECT EFI MAIN RELAY
A. Inspect relay continuity
(a) Using an ohmmeter, check that there is continuity between
terminals 1 and 2.
(b) Check that there is no continuity between terminals 3 and 5.
If continuity is not as specified, replace the relay.
B. Inspect relay operation
(a) Apply battery voltage across terminals 1 and 2.
(b) Using an ohmmeter, check that there is continuity between
terminals 3 and 5.
If operation is not as specified, replace the relay.
3. REINSTALL EFI MAIN RELAY EG±298
± ENGINESFI SYSTEM (2JZ±GTE)

EFI NO.2 RELAY
EFI NO.2 RELAY INSPECTION
1. REMOVE EFI NO.2 RELAY
LOCATION: In the engine compartment relay box.
2. INSPECT EFI NO.2 RELAY
A. Inspect relay continuity
(a) Using an ohmmeter, check that there is continuity between
terminals 1 and 2.
(b) Check that there is no continuity between terminals 3 and 5.
If continuity is not as specified, replace the relay.
B. Inspect relay operation
(a) Apply battery voltage across terminals 1 and 2.
(b) Using an ohmmeter, check that there is continuity between
terminals 3 and 5.
If operation is not as specified, replace the relay.
3. REINSTALL EFI NO.2 RELAY
± ENGINESFI SYSTEM (2JZ±GTE)EG±299

SOLENOID RESISTOR
COMPONENTS FOR REMOVAL AND
INSTALLATION
SOLENOID RESISTOR INSPECTION
1. DISCONNECT SOLENOID RESISTOR CONNECTOR
2. INSPECT SOLENOID RESISTOR
Using an ohmmeter, measure the resistance between termi-
nal +B and other terminals.
Resistance:
At 20°C (68°F) Approx. 6

If the resistance is not as specified, replace the resistor.
3. RECONNECT SOLENOID RESISTOR CONNECTOR EG±300
± ENGINESFI SYSTEM (2JZ±GTE)