Toyota MR2 1988 Repair Manual page 55

EM-12 ENGINE MECHANICAL - Engine Tune-up
5. FURTHER CHECK IDLE SPEED
Idle speed: 800 rpm
If the idle speed is not within this value carry out either of
the belowlisted procedures and then recheck the idle
speed.
Carry out a driving test, including stop-go several times at
a speed above 1 0 km/h, or start the engine, idle for 30
seconds and then turn the engine off repeatedly. By doing
this, idle data will be stored in the ISC and the idle rpm will
be at specified value.
IDLE HC/CO CONCENTRATION CHECK
METHOD
NOTE: This check is used only to determine whether or
not the idle HC/CO complies with regulations.
1. INITIAL CONDITIONS
2.
3.
(a) Engine at 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
NOTE: All vacuum hoses for EGR systems, etc. should
be properly connected.
(f) EFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in N range
(i) Tachometer and HC/CO meter calibrated and at
hand.
START ENGINE
CHECK OXYGEN SENSOR OPERATION
(a) Using a service wire, short the terminals T and E
1
of
the check connector.
(b)
(c)
Connect the positive ( +) probe of a voltmeter to ter-
minal VF of the check connector, and negative (-)
probe to terminal E
1 .
Hold the engine speed at 2,500 rpm for 90 seconds.
(d) Then, maintaining engine at 2,500 rpm, count how
many times needle of voltmeter fluctuates between 0
and 5 V.
Minimum needle fluctuation:
8 times for every 1 0 seconds
If the fluctuation is less than minimum, check the air
induction system. If necessary, see EFI SYSTEM.