Mazda 121 - Rough Idle;Engine Stalls at Idle - Always

TBOUBLESHOOTING GUIDE
F
a ROUGH IDLE/EXGINE STALLS AT IDLE
_
ALWAYS
DESCBP-
|
.Engrne
sads
normalv
bul stalls or v,brares excessvey al
idle in
every co']d
ion
FROUALESHOOTTNG
HtitTSl
O
Air/Fuel mixlure loo lean
.
Fuel injeciion
conlrol
malluncUon
.Low
luel line
pressure
@
Low
intake air amount
rn r^^^-4r iira clEAd
.
ldle speed
misadiust'nent
@
One or more spark
plugs
nol firlng
O
Low engine compression
@
Carbon deposit
in injecton body
INSPECTION ACTION
1 ls
"0O
drsplayed
on SeJi-Diagnosis Checker
wilh
ignition
swltch ON?
Mallunclion Code No. dlsplayed
Check for caus€ lRete. to soecilied
check sequence)
.? page
F-70
"8a"
tlaEhes
Check ECI.J lerminal 1F
voltag€ c?
page
F-114
Voltage Appro!. 12v
(lgnltion
€wltch O
)
+
ll
OK,
replace ECU
o
p.ge
F-112
+
ll nol OK, check
wlring betw€en
ECU and Sell Diagnosis
Check€r
2
Are
ECU teminal
voltages
OK?
(Esp€cially
1K,
2M, 20 and 20)
-r
page
F-112
Check tor cause
F
page
F-115
F-117
F-l19
3 Disconn€€l each hightension lead
al
idlei
does
engine speed decrease
equally at each cylinde?
Go to Step
5
ls
slrong blue spark
visible
at disconnected high-
/
Ch€ck hrghlension lead
F
psge
G-23
+
ll OK, check distr buto.
cap and
rotor
c7
p.ge
G-23
+
It nol OK, replace highlenson
5
Arc
spark
plugs
OK?
c7
page
G-19
WE1AF AND
CARBON
BUTLDUP
(0.039-0.0,*l
AURNS
DETERIOFAIION
Check tof corect engine
compression
rt'page
8-10
+
lf OK, replace injeclor
c?
Page
F-96
+
lf not OK, check tor cause
F
psge
B-10
Cean or
replace
F
page
G-19
F-29