The evaporative emission system's main job is to capture, store and send excess fuel vapors to be burned in order to prevent these vapors from escaping into the atmosphere.
Your vehicle's computer is constantly running a number of self tests to ensure the system is operating properly. The EVAP system plays a major role and affects your vehicle during the yearly state inspection.
The exhaust system's main job is to safely route away the left over gases from the combustion process away from the engine compartment with the help of the catalytic converter to "clean up" the more dangerous exhaust waste products while the oxygen sensor sends data to the ECU (engine control unit) to ensure optimum mixture of air to fuel in the engine cylinder by changing how much fuel is injected based on the sensors' readings.
The fuel tank obviously stores the gasoline when you fill up. But did you know that when people tell you not to continue filling the tank after the pump automatically stops it is because the tank has some expansion space at the top so the fuel can expand without overflowing or forcing the EVAP system to leak.
Tighten until click. The gas cap seals off the filler neck of the gas tank from the outside atmosphere. Damaged or missing gas caps are the most common cause of EVAP system failure codes that trigger the check engine light.
This canister is connected to the fuel tank by the tank vent line. The EVAP canister houses 1-2 pounds of activated charcoal that acts like a sponge by absorbing and storing fuel vapors until the purge valve opens and allows the vacuum of the engine intake to siphon the fuel vapors from the charcoal into the engine intake manifold.
This allows the flow of the fuel vapors from the fuel tank into the EVAP canister.
Allows engine intake vacuum to siphon the precise amount of fuel vapors from the EVAP canister into the engine intake manifold.
The means by which the fuel vapors flow to different components of the EVAP system.
Monitors the pressure within the fuel tank for leaks and to make sure too much pressure does not build.
This prevents liquid gasoline from entering the EVAP canister, which would overload its ability to store fuel vapors .
Function: Reduces the exhaust system's emissions.
Signs of Wear: Reduced engine performance and fuel economy, increased exhaust emissions.
Function: Senses oxygen content in the exhaust gas. The Powertrain Control Module (PCM) uses this input to optimize the combustion process.
Signs of Wear: Rough-running engine, poor fuel economy, "Service Engine Soon" light illuminates.
Function: Recirculates some of the engine's exhaust gas back into the intake manifold to be reburned, thereby reducing emissions.
Signs of Wear: Rough-running engine, engine hesitation or stalling, "Service Engine Soon" light illuminates.
Function: Controls internal pressure in the engine.
Signs of Wear: Engine runs rough or stalls.
Function: Reduces exhaust noise.
Signs of Wear: Loud exhaust.
Function: Collects exhaust gases from the cylinder head and diverts gases from each cylinder into a single pipe.
Signs of Wear: When the gasket leaks or when the exhaust manifold is cracked, exhaust gases enter the engine compartment instead of going through the exhaust system.
Professional Auto Care is a premier auto repair shop located in Southwest Houston. We offer repairs on exhaust system, evaporative emission system components and other emission repairs. We are located just outside Missouri City and Sugar Land.