Kia Sedona (2008 year). Instruction — part 329

PCV Valve installation: 7.8-11.8 N.m (0.8-1.2 kgf.m, 5.8-8.7 lbf. ft)

2008 Kia Sedona

2008 ENGINE PERFORMANCE Crankcase Emission Control System - Sedona

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2008 ENGINE PERFORMANCE

Evaporative Emission Control System - Sedona

DESCRIPTION

Evaporative Emission Control System prevents fuel vapor stored in fuel tank from vaporizing into the
atmosphere. When the fuel evaporates in the fuel tank, the vapor passes through vent hoses or tubes to the
canister filled with charcoal and the canister temporarily holds the vapor in the charcoal. If ECM determines to
draw the gathered vapor into the combustion chambers during certain operating conditions, it will use vacuum
in intake manifold to move it.

Fig. 1: Evaporative Emission Control System - Operation Diagram
Courtesy of KIA MOTORS AMERICA, INC.

CANISTER

canister is filled with charcoal and absorbs evaporated vapor in fuel tank. The gathered fuel vapor in canister is
drawn into the intake manifold by the ECM when appropriate conditions are set.

PURGE CONTROL SOLENOID VALVE (PCSV)

2008 Kia Sedona

2008 ENGINE PERFORMANCE Evaporative Emission Control System - Sedona

2008 Kia Sedona

2008 ENGINE PERFORMANCE Evaporative Emission Control System - Sedona

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Purge Control Solenoid Valve (PCSV) is installed in the passage connecting canister and intake manifold. It is a
duty type solenoid valve and is operated by ECM signal. To draw the absorbed vapor into the intake manifold,
the ECM will open the PCSV, otherwise the passage remains closed.

CANISTER CLOSE VALVE (CCV)

The Canister Close Valve (CCV) is located between canister and fuel tank air filter. It closes off the air inlet to
the canister for the Evaporative Emissions System leak detection inspection function and also prevents fuel
vapors from escaping from the Canister when the vehicle is not operating.

FUEL TANK PRESSURE SENSOR (FTPS)

The Fuel Tank Pressure Sensor (FTPS) is an integral part of the monitoring system. The FTPS, checks Purge
Control Solenoid Valve (PCSV) operation and leaks in the Evaporative Emission Control System by monitoring
pressure and vacuum level in the fuel tank during PCSV operating cycles.

FUEL FILLER CAP

A ratchet tightening device on the threaded fuel filler cap reduces the chances of incorrect installation, which
would seal the fuel filler. After the gasket on the fuel filler cap and the fill neck flange contact each other, the
ratchet produces a loud clicking noise indicating the seal has been set.

EVAPORATIVE SYSTEM MONITORING

Evaporative Emission Control Monitoring System consists of fuel vapor generation, evacuation, and leakage
check step. At first, the OBD-II system checks if vapor generation due to fuel temperature is small enough to
start monitoring, and then it evacuates the evaporative system by means of PCSV with ramp in order to
maintain a certain vacuum level. The final step is to check if there is vacuum loss by any leakage of the system.

VAPOR GENERATION CHECKING

During stabilization period, the PCSV and the CCV are closed, and the system pressure is measured as starting
pressure (DP_A). After a certain defined period (T1), the system pressure (DP_B) is measured again and the
difference from the starting pressure is calculated. If this difference (DP_B - DP_A) is bigger than a threshold,
there should be excessive vapor and the monitor is aborted for next checking. On the contrary, if the difference
is lower than another negative threshold, PCSV is regarded as malfunction such as clogged at open position.

EVACUATION

PCSV is opened with a certain ramp for the pressure to reach down to a certain level. If pressure can't be
lowered below a threshold, the system is regarded as fuel-cap-opened or having a large leakage.

LEAKAGE CHECKING

PCSV is closed and the system waits for a period to get stabilized pressure. During checking period (T2), the
system measures the beginning and the end of the system pressure (DP_C, DP_D). The diagnosis value is the
pressure difference corrected by natural vapor generation (DP_B - DP_A) rate from the vapor generation

2008 Kia Sedona

2008 ENGINE PERFORMANCE Evaporative Emission Control System - Sedona

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checking step.

EVAPORATIVE SYSTEM MONITORING

Fig. 2: Evaporative System Monitoring Graph
Courtesy of KIA MOTORS AMERICA, INC.

INSPECTION

1. Disconnect the vacuum hose from the throttle body, and connect a vacuum pump to the vacuum hose.

2. Check the following points when the engine is cold [engine coolant temperature 60°C (140°F) or below]

and when it is warm [engine coolant temperature 80°C (176°F) or higher].

WHEN ENGINE IS COLD

ENGINE COOLANT TEMPERATURE CHART

WHEN ENGINE IS WARM

ENGINE COOLANT TEMPERATURE CHART

Engine operating condition

Applied vacuum

Result

Idling

50 kPa (7.3 psi)

Vacuum is held

3,000 RPM

2008 Kia Sedona

2008 ENGINE PERFORMANCE Evaporative Emission Control System - Sedona

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