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

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Deceleration Spark Control System


The deceleration spark control system decreases hydrocarbon emissions during vehicle deceleration by advancing the ignition timing. Timing is advanced by a solenoid operated vacuum valve on the distributor. The solenoid changes vacuum supplied to the valve from ported (carburetor) to full manifold vacuum. The solenoid valve is controlled by the ECU based on engine speed.