Learn about your LTG - Evap System

The LTG’s EVAP System plays a crucial role in managing fuel vapors to prevent environmental pollution and ensure the efficient operation of the motor. Here's a detailed breakdown of its components and how they work together:

1. EVAP Purge Solenoid Valve:

• Controls the flow of fuel vapors from the EVAP canister to the intake manifold under the direction of the Engine Control Module (ECM).

2. EVAP Canister:

• Filled with carbon pellets that absorb and store fuel vapors until they can be safely consumed by the engine during combustion.

3. EVAP Vapor Tube:

• Allows fuel tank vapors to flow into the EVAP canister for storage and absorption.

4. Vapor Recirculation Tube:

• Facilitates diagnostics and service procedures by enabling testing of the EVAP system from different points.

5. Fuel Tank Pressure Sensor:

• Measures the pressure or vacuum inside the fuel tank to ensure proper system operation.

6. Fuel Filler Cap:

• Prevents fuel spit-back during refueling; in some vehicles, a capless design simplifies the refueling process.

7. Fuel Fill Pipe Inlet Check Valve:

• Ensures that fuel does not spill out during refueling.

8. Fuel Tank:

• Stores the vehicle's fuel supply.

9. EVAP Canister Vent Solenoid Valve:

• Controls the intake of fresh air into the EVAP canister during system testing.

10. Vent Hose:

• Allows excess pressure to be vented to the atmosphere to maintain system pressure.

11. EVAP Purge Tube:

• Transports the air/fuel vapor mixture from the canister to the intake manifold for combustion.

12. Purge Tube Check Valve:

• Prevents pressurization of the EVAP system in turbocharged applications to maintain system integrity.

Operation:

• Fuel tank vapors are directed into the EVAP canister, where they are absorbed by carbon pellets.

• Excess pressure is released through the vent hose and EVAP vent solenoid valve.

• The ECM opens the EVAP purge solenoid valve when necessary, allowing the engine vacuum to draw vapors from the canister into the intake manifold for combustion.

Diagnostic Tests:

• Purge Solenoid Valve Leak Test

• Large Leak Test

• Canister Vent Restriction Test

• Small Leak Test

EVAP System Components:

• Each component plays a specific role in managing fuel vapors and ensuring system integrity.

• Sensors like the Fuel Tank Pressure Sensor monitor system pressure to detect abnormalities.

Capless Fuel Fill:

• Some vehicles have a capless design for easier refueling and sealing after refueling.