Hyundai Sonata 1991 Shop Manual page 151

IGNITION SYSTEM
Ignition timing is controlled by the electric control ignition timing
system. The standard reference ignition timing data for the
engine operating conditions are programmed in the memory of
the electronic control unit (ECU).
The engine conditions (rpm, load, warm-up condition, etc.) are
detected by the various sensors. Based upon these sensor
signals and the ignition timing data, signals to interrupt the
primary current are sent to the power transistor. The ignition coil
is activated, and timing is controlled this way.
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Y27DAOA
IGNITION SYSTEM
GENERAL INFORMATION
TROUBLESHOOTING
Y27DBOA
Symptom Probable cause Remedy
Engine will not start or Incorrect ignition timing
Adjust ignition timing
hard to start. (Cranks
Ignition coil faulty
Inspect ignition coil
OK)
Power transistor faulty
Inspect power transistor
Distributor faulty
Inspect distributor
High tension cord faulty
Inspect high tension cord
Spark plugs faulty
Replace plugs
Ignition wiring disconnected or broken
Inspect wiring
Rough idle or stalls
Spark plugs faulty
Replace plugs
Ignition wiring faulty Inspect wiring
Incorrect ignition timing
Adjust ignition timing
Ignition coil faulty
Inspect ignition coil
Power transistor faulty Inspect power transistor
High tension cord faulty
Inspect high tension cord
Engine hesitates/poor
Spark plugs faulty Replace plugs
acceleration
Ignition wiring faulty Inspect wiring
Incorrect ignition timing Adjust timing
Poor gasoline mileage
Spark plugs faulty
Replace plugs
Incorrect ignition timing
Adjust ignition timing
Engine overheats
Incorrect ignition timing
Adjust ignition timing
27-32