Here's how the EVAP system works in your car to ventilate harmful gasoline vapors from escaping into the atmosphere:


I took apart the entire EVAP system to examine how it works on an Infiniti G35.

The most visible part of the EVAP system is the fuel filler neck:


But looking underneath, the gas tank, vacuum and filler tubes and EVAP canister comprise the majority of the system, seen here with the rear subframe removed:



Here's the EVAP canister, behind the rear right wheel area:




Inside the vehicle, the fuel pump (right) and fuel sending unit (left) are accessible underneath the rear seat:


Here's the gas tank dropped out:



Here's the entire EVAP system removed from the vehicle, from the gas tank and lines, the filler neck and tube to the charcoal canister and vacuum lines.



Here's the charcoal canister. The left most line is the vent, the right most is the purge line that goes to the air intake in the front of the vehicle, and the middle one leads from the gas tank.



Before cutting open the gas tank, I pumped out all the gasoline.



Fuel pump and sending unit removed:



I manually pumped another 3L of fuel after the fuel pump couldn't pump anymore.



I filled the tank with water and cut it open. Here you can see the baffles and the valving at the top of the tank:


A closer look at where the vent line and evap canister line connect to the gas tank. The smaller device (top) is the vapour cut off, and the larger device below is the fuel liquid separator, which prevents liquid gasoline from entering the charcoal canister.



Here's the tank cut open:



The float inside the liquid separator rises and shuts off the exit for any vapour that vents during refuelling.



Here's the charcoal canister chopped open. It's responsible for absorbing gasoline vapours and acts like a holding tank before it can be purged to the engine.




The gas cap is essential to holding pressure in the system during a self check. It features a spring loaded pressure relief valve as a safety in case pressure builds too much, it can vent.



The vent solenoid is simply an on/off air switch. When cut open, it is simply a coil that is energized to move a plunger in and out:



And that's all the main components of the EVAP system and how it works! Next time I'll open up the fuel pump and sending unit and go into deeper detail.



Enjoy

 

Y tho?

 

Because racecar...………………….

I think this kind of information is cool as hell. He's posted a few informative posts about different things G related and I love them. Not many people would have the time, the patience or the desire to put together these kinds of threads be the OP seems to enjoy it and I am grateful he does. Great work as always speedkar!!

 

Great post. Thank you.

 

awesome content and info. Thanks for of this.

 

Indeed indeed! I support this use of digital resources! Curiosity is the mother of invention, not Frank Zappa. Appreciations to OP.

 

Thanks, I'm glad you appreciate my work. I am fascinated with taking things apart and seeing how they work. I also like to film, document and photograph things to be helpful in teaching others, so putting these two together I took on the project of reverse-engineering this car.

Thanks very much all, I'll have more to come.

 

Nice stuff, I'm a little late to the party on this post but can you do a little further inspection on the components if you have them laying around still. There is a TSB and warranty extension that was sent out by Nissan in 2018 about a failure of the EVAP hose that was causing the vehicle to be very hard to fill with fuel. I think it was the smaller line going back up to the fuel fill inlet but it might have been the one going to the charcoal canister. Can you cut these two open and see if there is any significant debris or blockage either in the hose or at the bung going into the tank.

It would be awesome if you found EXACTLY where the issue is so folks in the future know exactly what to replace.

Here's the two items circled in red. I think one of them is what the warranty extension/TSB is about.

 

I know this is a blast from the past but I had to post and thank you. I've been working through many issues on my G35 Sedan and this visual and great explanation just saved me SO much hassle. I couldn't find this information anywhere.