,..,,...
CHECKING THE AIR INDUCTION SYSTEM
Air Injection
The air induction system burns unburned ex-
haust gases
by
in
jecting fresh air (secondary air)
into the exhaust port, reduc
in
g the emission
of
hydrocarbons. When there is negative pressure
at
t
he
ex
haust port, the reed valve opens, a
ll
ow-
ing secondary air to flow into the exhaust port.
The requir
ed
temperature for burning the un-
burned exhaust gases is approximately
600 to
700
•c (1112
to
1292 °F).
Air cut-off valve
The a
ir
cut-off val
ve
is con
tr
o
ll
ed by the signals
from the ECU in accordance with the combus-
tion conditions. Ordinarily, the air cut-off valve
opens to a
ll
ow the air to flow during idle and
closes to cut-off the flow when the vehicle is be-
ing driven. However, if the coolant temperature
is below the specified value, the air cut-off valve
remains open and a
ll
ows the air to flow into the
exhau
st
pipe until the temperatu
re
becomes
higher than the specified va
lu
e.
A. From the air
fi
lter case
B.
To
the cylinder head
1. Check:
• Hoses
Loose connections
-t
Connect proper
ly.
Cracks/damage
-t
Replace.
2. Check:
• Reed valve
• Reed valve stopper
• Reed valve seat
AIR INDUCTION SYSTEM
Cracks/damage
-t
Replace the reed valve
assembl
y.
3. Measure:
• Reed valve bending limit "a"
Ou1
of specification
-t
Replace the reed
val
ve
assembl
y.
~:
.
4. Check:
Reed valve bending limit
0.4 mm (0.02 in)
• Air cul-off valve
Cracks/damage
-t
Replace.
5.
Check
• A
ir
induction system solenoid
a
!
f
Refer to "CHECKING THE AIR INDUCTION
SYSTEM SOLENOID" on page 8
-1
08.
7-18
To Next Page
