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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Evaporative Emissions System: Testing and Inspection

Purge Port Vacuum Test:






1. Run engine at idle until warm [80-95°C (176-203°F)].
2. Disconnect the vacuum hose (red stripe) from the throttle body purge nipple and connect a vacuum gauge to the nipple.
3. START the engine and raise the engine speed to 2,500-3,000 RPM over a period of approximately 30 seconds while observing the vacuum gauge. Vacuum should remain constant regardless of engine speed.


NOTE: No vacuum at this nipple could indicate that the nipple is clogged. Clean nipple and retest vacuum.