Engine Stalls On Deceleration - Mazda MX-5 1990 Workshop Manual

F
TROUBLESHOOTING GUIDE
19 ENGINE STALLS ON DECELERATION
DESCRIP·
TION
• Engine unexpectedly stops running while decelerating or after deceleration -
[TROUBLESHOOTING HINTS]
Engine speed drops too much when releasing accelerator
CD
Idle speed control malfunction
®
Fuel cut control malfunction
STEP INSPECTION
1 Check if "00" is displayed on Self-Diagnosis
Checker with ignition switch ON
2
c:::T
page F-78
~-=
__
~ SYSTEM SELECT 1
TEST SW
.........:::::;;:;m=;;::;;f~SELF
TEST
Check switches for correct operation with 5elf-
Diagnosis Checker Monitor Lamp and ignition
switch
ON
SELECT SW A
c:7'
page F-89
SYSTEM SELECT 1
TEST SW
SELF TEST
3 Disconnect oxygen sensor connector and check
if condition improves
4 Check if ECU terminal voltages are
OK
(2D, 20, 2U, 2V and 20)
Yes
No
®
Engine feedback control malfunction
@)
Idle speed misadjustment
ACTION
Go to next step
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-80
c:7'
page F-128
¢
If OK, replace ECU c:::r page F-127
<=:>
If not
OK,
check wiring between
ECU and Self-Diagnosis Checker
c::::r page F-7
Yes
No
Go to next step
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
c:::T
page F-90
and Self-Diagnosis Checker
c::r
page F-7
Yes Check oxygen sensor
c:::r page F-138
No Go to next step
Yes Go to next step
c:7'
page F-129 No Check for cause (Refer to "Check Point
for Each Terminal") c:::r page
F-132
F-48
-,