Hyundai Sonata 1991 Shop Manual page 276

MPI SYSTEM
Check conditions
Test
Probable cause of malfunction
Check points
specification (or action)
EGR
temperature o Engine: warmed
Engine
Temperature o Check the EGR temperatLire sen-
sensor (California)
up (Engine is condition
°C (OF)
SOT.
o Service data
maintained in a
750 rpm
o Check the EGR control system.
o Item No.43
constant state
100 (212)
o Check the EGR valve.
(idling)
or less
for 2 minutes or
o ChElck the EGR control solenoid
more)
o 3,500 rpm
150 (302) valve.
o Disconnect
or more
o Check the EGR control vacuum.
the vacuum
hose (yel-
low stripe)
from the A
port nipple
of the throt-
tle body,
and pinch
the hose
end with
fingers.
Injectors
o Engine: idling Injector No.
Engine o If the
idling condition doesn't
o Actuator test
after warm-up
1
Idling condition
change, check the cylinder.
o Item No. 1-4
(Cut off the injec-
changes more.
1) Check the injector operation
tors in sequence 2
sound.
(Becomes more
during idling
3
unstable, or
2) Check the spark plug and high--
after engine war-
engine stalls.)
tension cable.
m-up; check the
4
3) Check the power transistor unit
idling condition.)
and control circuit.
Injector
0
Engine: warmed
Engine Activation
0
If the injector activation time is
o Service data
up condition
time (msec.)
unusually long or short, there is a
o Item No.41
750 rpm 2.5-4.0
malfunction of the air-flow sensor,
(Idling)
engine coolant temperature sen-
sor, intake-air temperature sensor,
2,000 rpm 2.5-4.0
or barometric pressure sensor.
Rapid racing
Increases.
o If the injector activation time is
long, increased engine resistance
or leakage of compression pres-
sure is probable.
Ignition advance
o Engine: warmed Engine speed
Ignition
o If the ignition advance and actual
(power transistor)
up (rpm)
advance
ignition timing are different, adjust
o Service data
o Timing light: set (OBTDe)
the ignition timing.
o Item NO.44
(The timing light
750 (Idling)
5-15
[The ignition timing may fluctuate
is set so as to
!luring idling, but this is not a prob-
check the actual 2,000
30-40 lem.
The
advance is greater
ignition timing.)
(approx. 5°) at high altitude.]
31-51