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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Deceleration Valve: Testing and Inspection


1. Loosen the hose clamp securing the over-run valve air feed hose to the throttle body and block the hose.
2. Start the engine; if idle is correct, stop engine and reconnect overrun valve.
3. Start engine, if the idle speed is not correct with valve connected, replace the overrun valve.