Toyota Supra 1990 Manual page 192

FI-18
EFI SYSTEM - Troubleshooting
SYMPTOM - HIGH ENGINE IDLE SPEED (NO DROP)
CHECK ACCELERATOR LINKAGE
BAD
Linkage - Stuck
1 0K
CHECK DIAGNOSIS SYSTEM
Malfunction
Diagnostic code(s) (See page FI-26)
Check for output of diagnostic code.
code(s)
(See page F 1-23)
!
Normal code
CHECK ISC SYSTEM
BAD
1. Wiring connection
(Air con, Throttle position sensor-ECU)
2. ISC valve
3. Air conditioner switch
1
OK
CHECK THROTTLE POSITION SENSOR
BAD
Throttle body
!
OK
CHECK FUEL PRESSURE
BAD
Fuel pressure regulator - High pressure
(See page FI-71)
t
OK
CHECK COLD START INJECTOR
BAD
Cold start injector - Leakage
(See page FI-77)
t
OK
CHECK INJECTORS (See page FI-83)
BAD
Injectors - Leakage, Injection quality
1
OK
CHECK EFI ELECTRONIC CIRCUIT
BAD
1. Wiring connection
USING VOLT/OHMMETER
2. Power to ECU
(See pages FI-30, 49)
(1) Fusible links
(2) Fuses (EFI 15A, IGN 7.5A)
(3) EFI main relay
3. Air flow meter
4. Water temp. sensor
5. Air temp. sensor
6. Injection signal circuit
(1) I njector wiring
(2) Resistor (7M-GTE)
(3) ECU