Q: Q: Evaporative Emissions Control

asked by on

Why does all my gas pour out on the ground when I pump gas? Its coming out up behind the rear tire.

My car has 200000 miles.
My car has a manual transmission.

Your car has a small purge valve that controls the venting of fumes from the fuel tank as these fumes build up inside, particularly when you are refueling the car with gas. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the charcoal canister. The charcoal canister is filled with activated carbon pellets that can absorb the fuel vapors. When the engine is running, the fuel vapors are purged from the canister and burned in the engine. The vent control valve (solenoid) controls the flow of outside air in and out of the charcoal canister. The vent valve is controlled by the engine computer (PCM). Normally the vent valve is open. It closes when the engine computer tests the EVAP system for leaks. If a leak in the EVAP system is detected, the Check Engine light will illuminate on the dash and the trouble code related to the problem will be stored in the engine computer.

When an air leak is present in the EVAP system, the MAP sensor will not be able to determine the air density, and the MAF sensor will not be able to determine the volume of air, entering the engine correctly. This will lead to an over fueling situation or an under fueling situation depending on the size of the air leak and engine operating speeds and load. This may eventually lead to catalytic converter problems as well as misfiring problems. I would recommend having an expert from Your Mechanic come to your home to take a look at your car to diagnose your EVAP purge solenoid.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Q: Evaporative Emissions Control

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: How to tighten battery connectors

Hello. Bolting connectors back on can be dangerous if you are not clear on how to do this. If you do not understand the mechanical (bolt on) connection between your cars electrical wiring to the battery terminals, for your own...

Q: vibrations and steering wheel shimmy/shake between 45-60 MPH.

Hey there, thanks for writing in. You may want to have the CV (constant velocity) joints and axles inspected. When these wear out or become damaged in any way, this can cause a vibrating problem at both high speeds and...

Q: My Jeep is having EVAP Issues

Hello Melissa, thank you for writing in. We can absolutely help you replace the EVAP canister or other malfunctioning parts in the system. If there is a vacuum leak in the system, you will need to locate it. An EVAP...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.