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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Cranking Signal: Description and Operation

PURPOSE
Voltage corresponding to engine RPM is supplied from the "tach" terminal on the distributor. Until a voltage signal equivalent to a predetermined RPM is received by the MCU, the system remains in the open loop mode, resulting in a rich air/fuel mixture for starting purposes.