Rough Idling And/Or Missing - Toyota MR2 1988 Repair Manual

Fl-14
EFI SYSTEM - Troubleshooting
SYMPTOM - ROUGH IDLING AND/OR MISSING
CHECK DIAGNOSIS SYSTEM
Malfunction Diagnositic code(s) (See pages Fl-24 to 27)
Check for output of diagnositic code.
code
(See page Fl-21)
~
Normal code
CHECK FOR VACUUM LEAKS IN AIR
BAD
1. Oil filler cap
INTAKE LINE 2. Oil level gauge
3. Hose connections
4. PCV hose
5. EGR system - EGR valve stays open
~
OK
CHECK AIR FILTER ELEMENT
BAD
Element Clean or replace
!
OK
CHECK IDLE SPEED
NO
Idle speed - Adjust (4A-GE)
STD: 800 rpm ISC system (4A-GZE)
~
OK
CHECK IGNITION TIMING
NO
Ignition timing - Adjust
1. Short terminals T and E1 of the
(See page IG-11)
check connector.
2. Check ignition timing.
STD: 1 0° BTDC
@
Idling
(w/short-circuited T- E,)
~
OK
CHECK SPARK PLUGS
NO
1 . Spark plug
Plug gap: 1.1 mm (0.043 in.) 2. Compression pressure
-Note-
Limit (at 250 rpm):
Check compression pressure and valve 4A-GE 10.0 kg/cm2
clearance if necessary.
(142 psi, 981 kpa)
(See page EM-14) 4A-GZE
8.5 kg/cm 2
(120 psi, 834 kpa)
3. Valve clearance (Cold)
STD: IN 0.15- 0.25 mm
(0.006 - 0.010 in.)
EX 0.20 - 0.30 mm
(0.008 - 0.012 in.)
!
OK
CHECK AIR CONTROL VALVE (4A-GE)
NO
1. VSV for air control valve
Check that the air control valve is
2. Vacuum leaks
closed.
~
OK
CHECK ISC VALVE (4A-GZE)
BAD
1.1SC valve
(See page Fl-1 06)
2. Wiring connection (See page Fl-60)
3. A/C switch
~
OK
CHECK COLD START INJECTOR
BAD
1 . Cold start injector
(See page Fl- 73) 2. Start injector time switch.
(See page Fl-11 5)
~
OK CONTINUED ON PAGE Fl-15