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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Fuel Injection Control


The amount of fuel injection is basically determined by the air flow sensor (AFS) output frequency corresponding to the amount of intake air. With the increase of air flow sensor output frequency, the amount of fuel injected increases and as the air flow sensor output frequency decreases, the amount of fuel injected decreases.