ENGINE AND EMISSION CONTROL SYSTEM 6E1-17
IDLE MIXTURE INSPECTION / ADJUSTMENT (VEHI-
CLE WITHOUT HEATED OXYGEN SENSOR)
All vehicles not equipped with heated oxygen sensor are shipped
with their CO % factory adjusted as follows.
Engine idle mixture (CO %)
0.5 – 1.5 % at specified idle speed
Idle mixture adjustment should never be changed from the origi-
nal factory setting. However, if during diagnosis, the check indi-
cates idle mixture to be the cause of a driver performance
complaint or emission failure, the idle mixture can be adjusted
using the following procedures.
1) Check idle speed according to “Idle Speed Inspection” sec-
tion.
2) Using exhaust gas tester, check that idle mixture CO % is
within above specification. If it is out of specification, adjust it
to specification by turning resistor knob.
3) If idle mixture has been adjusted, confirm that idle speed is
within specification. NOTE:
For this inspection and adjustment, exhaust gas tester
(CO meter) and engine tachometer are necessary.
NOTE:
Turning CO adjusting resistor knob to “A” increases CO
% (A/F mixture becomes rich) and turning it to “B”
decreases CO % (A/F mixture becomes lean).
1. CO adjusting resistor
