Idle Moves Up And Down/Idle Hunting - Mazda 121 Workshop Manual

TROUBLESHOOTING GUIDE
F
t 4
IDLE MOVES UP AI{O DOWN/IDLE HUNN G
DESCRIP. | .Engine spesds up and down periodically al idle
TroN I
5X?u68j*:SoorNG
HrNrsr
@ Throfle sensor misadjusted
@ Fuel injection amounl nconstant
@ Poor ignition
STEP INSPECTION
acrtot{
1
ls rhere a r leakaoe ar intake air svstem?
Repajr or replace leak€ge poinl
2
ls PCV valve OK?
cz page F-99
N O
3 ls arr cl€aner elemenl clean?
4 Disconnecl highlension lead at idle does en
gine speed decrease equally al each cylinder?
N o
Go 1o step 9
5
ls '00 displayed on SefDlagnosis Checker
wlh ignirion swtch oN?
e page F-57
TESi SWi SELF TEST
N O
Maltunction Code No. d|spl.ye.d
Check lor cause (Reler to speciied
check sequence) cr Page F-m
"84" flashes
Check ECU l€rminal lF voltage
17 Page F-114
vohage: Approx. 12v
(lgnition swilch ON)
+
lt OK, replace ECU
F page F-112
+
ll nol OK, check wins b€tween
ECU and Sell-Diagnosis Checker
6
Connecl Syslem Seleclor to diagnosis connector
and set Tesl Swilch to " SELF TEST'
Try known good ECU
F-39