Engine Stalls At Idle - Mazda MX-5 1990 Workshop Manual

F
TROUBLESHOOTING GUIDE
15 ENGINE STALLS AT IDLE - ALWAYS
DESCRIP·
TION
• Engine starts normally but vibrates excessively and stalls at idle in every condition
[TROUBLESHOOTING HINTS]
CD
Incorrect idle speed
• Idle speed misadjustment
-Idle speed control malfunction
STEP INSPECTION
®
Air/Fuel mixture too rich or lean
-Injector clogged or inoperative
- Low fuel line pressure
• Low intake air amount or air leakage
@
Poor ignition spark
ACTION
Check for correct intake manifold vacuum at idle Yes Go to next step
Vacuum: More than 450 mmHg (17.7 inHg)
,
2 Check if air cleaner element is clean
c:r page F-75
3 Check if "00" is displayed on Self-Diagnosis
Checker with ignition switch ON
c::r
page F-78
SELECT SW A
SYSTEM SELECT 1
4 Check switches for correct operation with Self-
Diagnosis Checker Monitor Lamp and ignition
switch ON
CT'
page F-89
SELECT SW A
F-42
No Check for air leakage of intake air sys-
tem components
c:r page F-93
Yes Go to next step
No Replace air cleaner element
Yes Go to next step
No Malfunction Code No. displayed
Check for cause (Refer to specified
check sequence)
, '88" flashes
Check ECU terminal
1 F
voltage
Voltage: Approx. 12V
(Ignition switch ON)
c::r page F-92
c::r
page F-80
CT'
page
F-128
c:::>
If OK. replace ECU
c::r
page F-127
c::::>
If not OK. check wiring between
ECU and Self-Diagnosis Checker
c:::r page F-7
Yes Go to next step
No
Lamp not ON/OFF with specified
switch
Check for cause (Refer to specified
check sequence)
Lamp always ON
Check wiring between ECU terminal 1 D
CT'
page
F-90
and Self-Diagnosis Checker
CT'
page F-7