Toyota Celica Supra 1986 Service And Repair Manual page 120

FI· 1B
EFI SYSTEM - Troubleshooting
SYMPTOM - ENGINE BACKFIRES-Lean Fuel Mixture
CHECK DIAGNOSIS SYSTEM Diagnostic codolsl
Check for output of diagnostic code.
Malfunction
ISee page Fl-26)
ISoe page Fl-221
code lsi
Normal code
CHECK FOR VACUUM LEAKS IN AIR
1 • Oil f iller cop
INTAKE LINE BAD
2.
Oil level gauge
3.
Hose connections
4. PCV hoses
5.
EGA system - EGA valve stays open
OK
CHECK IGNITION TIMING Ignition system ISee page IG -21
1. Short both terminals of the
BAD
cheek connector.
2. Check ignition timing.
STD: 10° BTDC
l w/ehort terminal s of the
cMck coi'W\8Ctor)
OK
CHECK COLD START INJECTOR
1 . Cold st art Injector
!Sea page F 1 -491
BAD
2.
Stan injector time switch
(See page Fl· 7 11
OK
CHECK FUEL PRESSURE
1.
Fuel pump tSee page F1·441
{See page Fl-451 BAD
2.
Fuel filter
3. Fuel pressure regulator !See page F1· 521
OK
CHECK INJECTORS
!See page Fl-531
BAD
'InJectors - clogged
I
OK
CHECK EFI ELECTRONIC CIRCUIT
1.
W iring connoction
USING VOLT/ OHMMETER
BAD
2. Power to ECU
I 11 Fusible link
121 No. 1 end No. 2 main relay
3 . Air flow meter
4.
Water temp. sensor
5.
Air temp. sensor
6.
Throttle position sensor
7.
Injection
signet
circuit
(1)
Injection wirings
1 21 Resist or
1 31 ECU
1 41 Fuel cut sig<1al
8. Oxygen sensor