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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KN3 - Check FPRC Vacuum Supply

- Key "OFF".

- Tee in a standard vacuum gauge at the hose between the manifold vacuum source and the Fuel Pressure Regulator Control (FPRC) solenoid input vacuum port.

- Start and idle engine while observing the vacuum gauge needle.

- Was a vacuum signal present?

Yes -- Remove vacuum gauge. Go to KN4. KN4 - Check FPRC Vacuum Hose to Fuel Pressure Regulator

No -- Address base engine vacuum source concern.