Rough Idle/Engine Stalls At Idle - Always - Mazda 121 Workshop Manual

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