Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Electronic Spark Advance (ESA) Control


The ECU is programmed with data for optimum ignition timing for all engine operating conditions. Using data from sensors which monitor engine operating conditions, the ECU controls ignition module operation to trigger spark at precisely the right moment to ensure complete combustion. For a complete description, diagnosis and testing of this system, refer to ``Electronic Ignition.''