What does the evaporative emission control system do?

It reduces hydrocarbons emitted to the atmosphere from the fuel system; the reduction is accomplished by activated charcoals in the carbon canister.

What happens to fuel vapor when the engine is stopped?

Fuel vapor from the sealed fuel tank is led into the carbon canister, which is filled with activated carbon, and is stored there.

How do I begin inspecting the carbon canister purge control valve?

Disconnect the rubber hose in the line between the T-connector and carbon canister, at the T-connector.

Where can I find inspection info for the fuel tank and vapor vent line?

The document refers to the MA section for inspection of the fuel tank and vapor vent line.

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Nissan Evaporative Emission Control System - EVAP Diagram & Operation (EF & EC-33)

Evaporative Emission Control System routing diagram with carbon canister, Nissan EF & EC

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Evaporative emission control routing: fuel vapor from the sealed tank is stored in the carbon canister and purged to the intake manifold through the purge control valve.

AI caption June 2005 · Photo 133 of 412

This page is from a Nissan factory service manual section on Exhaust Emission Control, specifically covering the Evaporative Emission Control System. It explains that the system reduces hydrocarbons emitted to the atmosphere from the fuel system by trapping fuel vapors in activated charcoal inside a carbon canister. A schematic diagram (reference SEC261A) shows the vapor routing between the throttle valve, intake manifold, carbon canister, purge control valve, fuel check valve, fuel vapor vent line, fuel tank, and fuel filler cap with vacuum relief valve, with arrows distinguishing fuel vapor flow at engine running versus engine stop. The Operation section describes system behavior at engine stop (vapor from the sealed fuel tank is stored in the canister) and during engine operation (air drawn through the purge line cleans the canister; as engine speed increases, ported vacuum rises and the purge control valve opens, letting vapor travel to the intake manifold). The Inspection section refers the reader to the MA section for fuel tank and vapor vent line inspection and begins the carbon canister purge control valve inspection procedure by instructing to disconnect the rubber hose between the T-connector and carbon canister. The page is numbered EF & EC-33.

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Frequently asked questions

What does the evaporative emission control system do?: It reduces hydrocarbons emitted to the atmosphere from the fuel system; the reduction is accomplished by activated charcoals in the carbon canister.
What happens to fuel vapor when the engine is stopped?: Fuel vapor from the sealed fuel tank is led into the carbon canister, which is filled with activated carbon, and is stored there.
How is the carbon canister purged during engine operation?: The canister retains the vapor until it is cleaned by air drawn through the purge line to the intake manifold. As engine speed increases, ported vacuum rises and the purge control valve opens the orifice, allowing vapor to travel through the purge line to the intake manifold.
How do I begin inspecting the carbon canister purge control valve?: Disconnect the rubber hose in the line between the T-connector and carbon canister, at the T-connector.
Where can I find inspection info for the fuel tank and vapor vent line?: The document refers to the MA section for inspection of the fuel tank and vapor vent line.