Toyota 4A-FE Repair Manual page 92

EFI SYSTEM - Troubleshooting Fl-21
~OK
CONTINUED FROM PAGE Fl-20
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CHECK FUEL PRESSURE
Fuel pressure regulator - High pressure
(See page Fl-97)
BAD
i
OK
I
Cold start injector - Linkage
CHECK COLD START INJECTOR
I
(See page Fl-105)
BAD
CHECK INJECTORS
Injectors - Leakage, Injection quantity
(See page Fl-111)
BAD
i
OK
CHECK EFI ELECTRONIC CIRCUIT 1. Wiring connection
-
USING VOLT/OHMMETER BAD 2. Power to ECU
(See page Fl-34)
{1} Fusible link(s)
(2) Fuse(s)
(3)
EFI main relay
3 . Air flow meter
(w/
Air flow meter)
4 . Vacuum sensor (w/o Air flow meter)
5. Water temp. sensor
6 . Intake air temp. sensor
7. Injection signal circuit
(1) Injector wiring
(2) ECU
SYMPTOM - ENGINE BACKFIRES-Lean Fuel Mixture
CHECK DIAGNOSIS SYSTEM Diagnostic code(s)
Check for output of diagnostic code. Malfunction 4A-FE (See page Fl-28)
(See page Fl-25) code(s)
!
Normal code
CHECK FOR VACUUM LEAKS IN AIR
-
1. Oil dipstick
INTAKE LINE
BAD 2. Hose connection(s)
3. PCV hose(s)
4. EGA system - EGR valve stays open
!
OK
CHECK IGNITION TIMING
Ignition timing - Adjust
1. Connect terminals TE1 and E1 of the
NO
4A-FE (See page EM-20)
check connector
2. Check ignition timing .
Standard:
1 0° BTDC
@
idle
i
OK
CHECK IDLE SPEED (AND IDLE CO
------
.
1. Idle speed - Adjust
CONCENTRATION) NO 4A-FE (See pages EM-22, 23)
Standard: 800 rpm
2. Idle CO concentration - Adjust
l
OK
CONTINUED ON PAGE Ft-22