Toyota COMPUTER-CONTROLLED SYSTEM Training Manual page 92

®
ESA - Genera l
2 . IGNITION TIMING AND GASOLINE
QUALIT Y
ESA
Governor
advance r
Engine speed -
Hig h
ADVANCING BY ENGINE SPEE D
Ideal ignitio n
Manifold vacuum
-
Hig h
VACUUM ADVANCIN G
timing
I
ESA
OHP 5 9
Vacuum advance r
OHP 59
In some engine models, two ignition timing
advance patterns, according to the fuel octane
rating ( premium or regular), are stored in the
ECU . The ignition timing can be changed to match
the gasoline being used (premium or regular) by
operating the fuel control switch or connector
(See page 40) .
In some engine models, this is done automatically
by the Engine ECU's fuel octane judgement fun-
ction (See page 116) .
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