90
Seconds
ENGINE
MECHANICAL
- Engine Tune-up (4A-FE)
EM-23
Tachometer
rpm
EC0163
HC/CO
Meter
EM7454
INSPECTION'
AND
ADJUSTMENT
OF
IDLE SPEED
AND
IDLE
MIXTURE
(w/o
TWC)
1.
INITIAL
CONDITIONS
(a)
Air
cleaner installed
(b}
Normal engine operating temperature
(c)
All pipes and hoses
of
air induction
system con-
nected
{d)
All accessories switched
off
{e)
EFI
system wiring connectors
fully
plugged
{f)
Ignition timing set correctly
(g]
Transmission
in
"neutral"
range
(h}
HC/CO meter operates normally
2.
WARM
UP ENGINE
Allow
the
engine
to
reach normal operating temperature.
3.
CONNECT
TACHOMETER
(See
page
EM-20)
4.
CHECK
AIR
VALVE
OPERATION
(See page
Fl-131)
5. INSPECT
AND
ADJUST
IDLE SPEED
6.
Idle
speed:
800
rpm
(w/
Cooling
fan
OFF)
If
not
as
specified, adjust the idle speed
by
turning the
IDLE
SPEED
ADJUSTING
SCREW.
ADJUST
IDLE
MIXTURE
NOTICE:
Always
use
a HC/CO
meter
when
adjusting
the
idle
mixture.
It
is
not
necessary
to
adjust
with
the
idle
mixture
adjusting
screw
in
most
vehicles
if
they
are
in
good
condition.
If
a CO
meter
is
not
available#
DO
NOT
ATTEMPT
TO
ADJUST
IDLE
MIXTURE.
(a)
Race
the
engine
at
2,500
rpm
for
approx.
90
seconds.
(b)
Insert a testing probe
at
least
40
cm (1.3 ft} into the
tailpipe.
(c) Measure the concentration 1 - 3 minutes after racing
the engine to allow
the
concentration to stabilize.
Idle
CO
concentration:
1.5
±
0.5
%
(w/
Cooling
fan
OFF)
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