1986 TOYOTA SUPRA check engine

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

VSV FOR FUEL PRESSURE CONTROL
COMPONENTS FOR REMOVAL AND
INSTALLATION
VSV INSPECTION
1. REMOVE VSV
2. INSPECT VSV
A. Inspect VSV for open circuit
Using an ohmmeter, check that there is continuity between
the terminals.
Resistance:
At 20°C (68°F) 33±39

If there is no continuity, replace the VSV.
B. Inspect VSV for ground
Using an ohmmeter, check that there is no continuity be-
tween each terminal and the body.
If there is continuity, replace the VSV.
± ENGINESFI SYSTEM (2JZ±GTE)EG±301

C. Inspect VSV operation
(a) Check that air flows from port E to G.
(b) Apply battery voltage across the terminals.
(c) Check that air flows from port E to the filter.
If operation is not as specified, replace the VSV.
3. REINSTALL VSV
VSV FOR INTAKE AIR CONTROL VALVE
COMPONENTS FOR REMOVAL AND
INSTALLATION
EG±302± ENGINESFI SYSTEM (2JZ±GTE)

VSV INSPECTION
1. REMOVE VSV
2. INSPECT VSV
A. Inspect VSV for open circuit
Using an ohmmeter, check that there is continuity between
the terminals.
Resistance:
At 20°C (68°F) 38.5±44.5

If there is no continuity, replace the VSV.
B. Inspect VSV for ground
Using an ohmmeter, check that there is no continuity be-
tween each terminal and the body.
If there is continuity, replace the VSV.
C. Inspect VSV operation
(a) Check that air flows from port E to the filter.
(b) Apply battery voltage across the terminals.
(c) Check that air flows from port E to F.
If operation is not as specified, replace the VSV.
3. REINSTALL VSV
± ENGINESFI SYSTEM (2JZ±GTE)EG±303

VSV FOR WASTE GATE VALVE
COMPONENTS FOR REMOVAL AND
INSTALLATION
VSV INSPECTION
1. REMOVE VSV ASSEMBLY
2. INSPECT VSV
A. Inspect VSV for open circuit
Using an ohmmeter, check that there is continuity between
the terminals.
Resistance:
At 20°C (68°F) 22±26

If there is no continuity, replace the VSV.
B. Inspect VSV for ground
Using an ohmmeter, check that there is no continuity be-
tween each terminal and the body.
If there is continuity, replace the VSV. EG±304
± ENGINESFI SYSTEM (2JZ±GTE)