Toyota 4A-FE Repair Manual page 23

ENGINE MECHANICAL - Idle HC/CO Concentration Method (w/ TWC) EM-33
Check Connector
1
.' \ 1 . .
j
Voltmeter
v+
....___~
IDLE HC/CO CONCENTRATION
CHECK METHOD
(w/
TWC)
HINT: This check is used only to determine whether or
not the idle HC/CO complies with regulations.
1. INITIAL CONDITIONS
(a)
Engine to reach normal operating temperature
(b) Air cleaner installed
(c)
All pipes and hoses of air induction system con-
nected
(d) All accessories switched off
{e) All vacuum lines properly connected
HINT:
All vacuum hoses for EGA systems, etc. should be
properly connected.
(f) EFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral range
(i) Tachometer and HC/CO meter calibrated and at
hand.
2. START ENGINE
3. CHECK IDLE SPEED
SST Idle speed: 800 rpm
EM7502
4.
CHECK OXYGEN SENSOR OPERATION
(a)
Using SST, connect the terminal TE 1 and E 1 of
the
check connector.
SST 09843-18020
(b)
Connect the positive
(+)
probe of
a
voltmeter to ter-
minal VF1 of the check connector, and negative (-)
probe to terminal
E1.
(c)
Hold the engine speed
at
2,500
rpm for approx.
90
seconds to warm up the oxygen sensor.
(d) Then, maintaining engine at
2,500
rpm. count how
many times the needle of the voltmeter fluctuates
between 0 and 5 V.
Minimum needle fluctuation:
4A-FE 8 times for every 10 seconds
If the fluctuation is less than minimum, check the air
induction system.
tf
necessary, see EFI SYSTEM.