1986 TOYOTA SUPRA check engine

KNOCK SENSORS INSPECTION
1. REMOVE THROTTLE BODY
(See throttle body removal)
2. REMOVE STARTER
(See starter removal in Starting System)
3. REMOVE KNOCK SENSORS
(a) Disconnect the knock sensor connector.
(b) Using SST, remove the knock sensor.
SST 09816±30010
4. INSPECT KNOCK SENSORS
Using an ohmmeter, check that there is no continuity be-
tween the terminal and body.
If there is continuity, replace the sensor.
5. REINSTALL KNOCK SENSORS
(a) Using SST, install the knock sensor.
SST 09816±30010
Torque: 44 NVm (450 kgfVcm, 33 ftVlbf)
(b) Connect the knock sensor connector.
6. REINSTALL STARTER
(See starter installation in Starting System)
7. REINSTALL THROTTLE BODY
(See throttle body installation)
± ENGINESFI SYSTEM (2JZ±GTE)EG±317

(See page EG±788)
(See page EG±788)
Warm up the oxygen sensor with the engine
at 2,500 rpm for approx. 120 seconds.
Connect terminals TE1 and E1 of the data link connector 1.
And maintain engine speed at 2,500 rpm.
Check the number of times the voltmeter needle fluctuates in 10 seconds.
Less than 8 times
Warm up the oxygen sensor with the engine at
2,500 rpm for approx. 120 seconds. And maintain
engine at 2,500 rpm.
Check the number of times the voltmeter needle
fluctuates in 10 seconds.
Less than 8 times
Disconnect terminates TE1 and E1 of the data link connector1. And maintain engine speed at 2,500 rpm.
Measure voltage between terminals VF1 (VF2) and E1.
More than 0 V
Read and record diagnostic trouble codes. (See page EG±788)
Normal code, codes Nos.
21, 25, 26 and 26Malfunction code(s)
(Except code Nos. 21, 25, 26 and 26)
Repair the relevant diagnostic trouble code.
Malfunction code(s)
(Except code Nos. 21, 25, 26)
Read and record diagnostic trouble codes. (See page EG±788)
Normal code, codes Nos. 21, 25, 26
Disconnect terminals TE1 and E1 of the data link connector 1.
And maintain engine speed at 2,500 rpm.
Measure voltage between terminals VF1 (VF2) and E1.
Repair
(Over rich)
More
than 0 V
Disconnect the PCV hose.
Measure voltage between terminals VF1 and E1.
Disconnect the ECT sensor connector, and connect resistor
with a resistance of 4 ± 8k
or send an equivalent simulation
signal.
Connect terminals TE1 and E1 of the data link connector 1.
Warm up the oxygen sensor with the engine at
2,500 rpm for approx. 120 seconds. And maintain engine
speed at 2,500 rpm.
Measure voltage between terminals VF1 and E1.
Repair (Over lean)Replace the oxygen sensor.
After replacing
the oxgen
sensor.
Replace he ECM.
± ENGINESFI SYSTEM (2JZ±GTE)EG±319

FUEL CUT RPM
FUEL CUT RPM INSPECTION
1. WARM UP ENGINE
Allow the engine to warm up to normal operating tempera-
ture.
2. CONNECT TACHOMETER TO ENGINE
Connect the tester probe of a tachometer to terminal IG
of
the DLC1.
NOTICE:
wNever allow the tachometer terminal to touch ground as
it could result in damage to the igniter and/or ignition
coil.
wAs some tachometers are not compatible with this igni-
tion system, we recommend that you confirm the compat-
ibility of your unit before use.
3. INSPECT FUEL CUTOFF OPERATION
(a) Increase the engine speed to at least 3,000 rpm.
(b) Check for injector operating noise.
(c) Check that when the throttle lever is released, injector
operation noise stops momentarily and then resumes.
HINT: Measure with the A/C OFF.
Fuel return speed:
1,400 rpm
(Vehicle speed less than 25 km/h (16mph), with
brake OFF)
4. DISCONNECT TACHOMETER EG±326
± ENGINESFI SYSTEM (2JZ±GTE)

09843±18020 Diagnostic Check Wire
09990±01000Engine Control Computer Check
Harness ªAº
RECOMMENDED TOOLS
09082±00050 TOYOTA Electrical Tester Set
09200±00010Engine Adjust Kit
09258±00030 Hose Plug SetPlug for vacuum hose, fuel
hose etc.
EQUIPMENT
 Carburetor cleaner 
 
 Graduated cylinder 
 Injector
 Soft brush 
 Sound scope Injector
 Tachometer 
 Torque wrench 
 
 Vacuum gauge
 
 
COOLANT 
 Item
 
 Capacity
 
 Classification
 
 
Engine coolant (w/ Heater) M/T
A/T 
 
7.3 liters (7.7 US qts, 6.4 lmp. qts)
8.3 liters (8.8 US qts, 7.3 lmp. qts) 
 
Ethylene±glycol base
EG±188± ENGINESFI SYSTEMS (2JZ±GE)

PRECAUTION
1. Before working on the fuel system, disconnect the
negative (±) terminal cable from the battery.
HINT: Any diagnostic trouble code retained by the computer
will be erased when the negative (±) terminal cable is discon-
nected.
Therefore, if necessary, read the diagnosis before discon-
necting the negative (±) terminal cable from the battery.
2. Do not smoke or work near an open flame when working
on the fuel system.
3. Keep gasoline away from rubber or leather parts.
MAINTENANCE PRECAUTIONS
1. PRECAUTION WHEN CONNECTING GAUGE
(a) Use ba tte ry as th e po we r so u rce fo r th e timin g lig h t,
tachometer, etc.
(b) Connect the tester probe of a tachometer to the terminal IG

of the DLC1.
2. IN EVENT OF ENGINE MISFIRE, FOLLOWING
PRECAUTIONS SHOULD BE TAKEN
(a) Check proper connection of battery terminals, etc.
(b) Handle high±tension cords carefully.
(c) After repair work, check that the ignition coil terminals and all
other ignition system lines are reconnected securely.
(d) When cleaning the engine compartment, be especially
careful to protect the electrical system from water.
3. PRECAUTIONS WHEN HANDLING OXYGEN SENSOR
(a) Do not allow oxygen sensor to drop or hit against an object.
(b) Do not allow the sensor to come into contact with water.
± ENGINESFI SYSTEM (2JZ±GE)EG±189

IF VEHICLE IS EQUIPPED WITH MOBIL
RADIO SYSTEM (HAM, CB, ETC.)
If the vehicle is equipped with a mobile communication sys-
tem, refer to the precaution in the IN section.
AIR INDUCTION SYSTEM
1. Separation of the engine oil dipstick, oil filler cap, PCV hose,
etc. may cause the engine to run out of tune.
2. Disconnection, looseness or cracks in the parts of the air
induction system between the throttle body and cylinder
head will cause air suction and cause the engine to run out
of tune.
ELECTRONIC CONTROL SYSTEM
1. Before removing SFI wiring connectors, terminals, etc., first
disconnect the power by either turning the ignition switch
OFF or disconnecting the negative (±) terminal cable from the
battery.
HINT: Always check the diagnostic trouble code before dis-
connecting the negative (±) terminal cable from the battery.
2. When installing the battery, be especially careful not to
incorrectly connect the positive (+) and negative (±) cables.
3. Do not permit parts to receive a severe impact during removal
or installation. Handle all SFI parts carefully, especially the
ECM.
4. Do not be careless during troubleshooting as there are
numerous transistor circuits and even slight terminal contact
can cause further troubles.
5. Do not open the ECM cover.
6. When inspecting during rainy weather, take care to prevent
entry of water. Also, when washing the engine compartment,
prevent water from getting on the SFI parts and wiring
connectors.
7. Parts should be replaced as an assembly.
8. Care is required when pulling out and inserting wiring
connectors.
(a) Release the lock and pull out the connector, pulling on the
connectors.
(b) Fully insert the connector and check that it is locked. EG±190
± ENGINESFI SYSTEMS (2JZ±GE)

3. Observe the following precautions when removing and
installing the injectors.
(a) Never reuse the O±ring.
(b) When placing a new O±ring on the injector, take care not to
damage it in any way.
(c) Coat a new O±ring with spindle oil or gasoline before
installing±never use engine, gear or brake oil.
4. Install the injector to the delivery pipe and intake manifold as
shown in the illustration.
5. Check that there are no fuel leaks after doing maintenance
anywhere on the fuel system.
(a) Using SST, connect terminals +B and FP of the DLC 1.
SST 09843±18020
(b) With engine stopped, turn the ignition switch ON.
(c) Pinch the fuel return hose.
The pressure in the high pressure line will rise to approx. 392
kPa (4 kgf/cm
2, 57 psi). In this state, check to see that there
are no leaks from any part of the fuel system.
NOTICE: Always pinch the hose. Avoid bending as it may
cause the hose to crack.
(d) Turn the ignition switch OFF.
(e) Remove the SST from the DLC1.
SST 09843±18020 EG±192
± ENGINESFI SYSTEM (2JZ±GE)

FUEL PUMP
ON±VEHICLE INSPECTION
1. CHECK FUEL PUMP OPERATION
(a) Using SST, connect terminals +B and FP of the DLC 1.
SST 09843±18020
(b) Turn the ignition switch ON.
NOTICE: Do not start the engine.
(c) Check that there is pressure in the fuel inlet hose from the fuel
filter.
HINT: If there is fuel pressure, you will hear the sound of fuel
flowing.
If there is no pressure, check the following parts:
wFuse
wEFI main relay
wFuel pump
wECM
wWiring connections
(d) Turn the ignition switch OFF.
(e) Remove the SST from the DLC1.
SST 09843±18020
2. CHECK FUEL PRESSURE
(a) Check the battery voltage is above 12 V.
(b) Disconnect the negative (±) terminals cable from the battery.
(c) Remove the 2 nuts, and disconnect the No.2 vacuum pipe
from the air intake chamber and intake manifold.
(d) Remove the union bolt and 2 gaskets, disconnect the fuel
inlet pipe from the delivery pipe.
CAUTION:

Put a shop towel under the delivery pipe.

Slowly loosen the union bolt.
(e) Install the fuel inlet pipe and SST (pressure gauge) to the
delivery pipe with the 3 gaskets and SST (union bolt).
SST 09268±45012
Torque: 42 NVm (420 kgfVcm, 30 ftVlbf)
(f) Wipe off any splattered gasoline.
(g) Using SST, connect terminals +B and FP of the DLC 1.
SST 09843±18020
± ENGINESFI SYSTEM (2JZ±GE)EG±193