TOYOTA SUPRA 1986 Service Repair Manual

MAS AIR FLOW (MAF) METER
COMPONENTS FOR REMOVAL AND
INSTALLATION
MAF METER REMOVAL
Installation is in the reverse order of removal.
1. REMOVE NO.1 AIR HOSE
2. REMOVE AIR CLEANER HOSE
3. REMOVE MAF METER
(a) Remove the 2 bolts, and disconnect the MAF meter from the
air cleaner case.
Torque: 6.9 NVm (70 kgfVcm, 61 in.Vlbf)
(b) Disconnect the MAF meter wire from the wire clamp on the
air cleaner case.
(c) Disconnect the MAF meter connector, and remove the MAF
meter.
± ENGINESFI SYSTEM (2JZ±GTE)EG±287

MAF METER INSPECTION
1. INSPECT MAF METER RESISTANCE
Using an ohmmeter, measure the resistance between termi-
nals THA and E2.
 
 
Between
terminals 
 Resistance
 
 Temperature
 THA±E2 10±20 k
 ±20°C (±4°F)
 THA±E2 4±7 k
 0°C (32°F)
 THA±E2 2±3 k
 20°C (68°F) THA±E2 0.9±1.3 k
 40°C (104°F) THA±E2 0.4±0.7 k
 60°C (140°F)
If the resistance is not as specified, replace the MAF meter.
2. INSPECT MAF METER OPERATION
(a) Connect the MAF meter connector.
(b) Connect the negative (±) terminal cable to the battery.
(c) Using a voltmeter, connect the positive (+) tester probe to
terminal VG, and negative (±) tester probe to terminal E21.
(d) Turn the ignition switch ON.
(e) Blow air into the MAF meter, and check that the voltage
fluctuates.
If operation is not as specified, replace the MAF meter.
(f) Turn the ignition switch OFF.
(g) Disconnect the negative (±) terminal cable from the battery.
(h) Disconnect the MAF meter connector. EG±288
± ENGINESFI SYSTEM (2JZ±GTE)

THROTTLE BODY
ON±VEHICLE INSPECTION
Throttle Body
INSPECT THROTTLE BODY
(a) Check that the throttle linkage moves smoothly.
(b) Check the vacuum at the purge port.
wStart the engine.
wCheck the vacuum with your finger.
 Port name At idle At 3,000 rpm
 Purge No vacuum Vacuum
Dashpot
1. WARM UP ENGINE
Allow the engine to warm up to normal operating tempera-
ture.
2. CHECK IDLE SPEED
Idle speed (Transmission in neutral position):
650
+ 50 rpm
3. CHECK AND ADJUST DASHPOT SETTING SPEED
(a) Disconnect the control cables from the throttle body.
(b) Turn the throttle linkage until the dashpot adjusting screw
starts to separate from the push rod. Then keep the throttle
linkage at that position.
(c) Check that the dashpot is set.
Dashpot setting speed:
2,300 + 400 rpm
(d) Reconnect the control cables to the throttle body.
4. CHECK VTV OPERATION
(a) Maintain the engine speed at 3,500 rpm.
(b) Release the throttle valve, and check that the engine returns
to idle in a few seconds.
± ENGINESFI SYSTEM (2JZ±GTE)EG±289

Throttle Opener
1. WARM UP ENGINE
Allow the engine to warm up to normal operating tempera-
ture.
2. CHECK IDLE SPEED
Idle speed (Transmission in neutral position):
650 + 50 rpm
3. CHECK THROTTLE OPENER SETTING SPEED
(a) Disconnect the throttle opener vacuum hose from the throttle
body, and plug the throttle body port.
(b) Maintain the engine speed at 2,500 rpm.
(c) Release the throttle valve.
(d) Check that the throttle opener is set.
Throttle opener setting speed:
1,500 + 200 rpm
(e) Adjust the throttle opener setting speed by turning the throttle
opener adjusting screw.
(f) Reconnect the throttle opener vacuum hose to the throttle
body.
COMPONENTS FOR REMOVAL AND
INSTALLATION
EG±290± ENGINESFI SYSTEM (2JZ±GTE)

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)