EVAP Line???
 

What are you guys doing with the EVAP line that runs from the gas tank?? As a follow on,,, is it just a vent line from the tank or are there other mechanicals on the tank end??

Mine's just disconnected dangling in the engine bay. Never quite figured out if this is bad thing but it's been that way for years now.

I was told to cap it. So I cut and crimped it at the back of the car. Kind of hoping that isn't my fueling issue

I took the metal line out all the way back to the canister...I haven’t quite figured out what I’m going to do with it yet. I need to figure out how the factory system is vented.

Glad I'm not alone on this. In reviewing the diagrams below,,, wish I'd of pulled the purge valve off the motor before I sold it.

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Any news on this?

bringing this thread to life... in a engine swqp situation with no OEM ecu.
how to vent properly ..etc maybe some check valves ? im suspecting I killed my oem fuel pump because of some issue with this system

I replied in your thread. I don't believe EVAP has anything to do with the dead pump. Mine was capped for years and now is simply open all the time.

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Mine is vented, I believe. I haven't seen a problem with anything.

There are valves in the system that should open with pressure or are always open. The EVAP/ECU system closes the vent valve/solenoid and opens the EVAP solenoid under the intake manifold to suck fumes into the intake manifold when it senses pressure build, normally. It doesn't do this with the car off, so the gas cap should hiss from pressure buildup. Without the ECU, I believe the system is open and should vent, or it should vent at a certain pressure when a valve receives a certain pressure.

You could drop the tank and remove the system and vent it if you want.

My line in the engine bay is open to atmos as well.. so this line relieves pressure from the tank in this case... what about the lines that bring fresh air in the fuel tank?

The gas cap is vented? I saw a thread were the filler tubes collapsed big issues---so the gas cap should hiss from pressure buildup.---

I wish I knew this for sure...searched everywhere cant find info on this unfortunatly ---Without the ECU, I believe the system is open and should vent, or it should vent at a certain pressure when a valve receives a certain pressure.--

I would be willing to install check valves on lines and remove the whole EVAP thing under the car but dont know which lines are which... its definitly not the most exciting part of a build but the most dangerous one I hear...

Just follow the line. Anything that doesn't carry fuel to the motor or is part of the fill tube can be deleted

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There is actually only one fuel line at the back of the car the bifurcates into two lines, and it is the same size hose, so it isn't like both lines are need. The other engine bay hose is bring fuel vapor to the EVAP, so in all, you can lose two of the three lines. I have AN lines now for my feed and return. The hose running to the engine bay from the back is just cut and hanging between the body and fuel tank at the back of the car. The rest of the hoses from the system are buried on top of the fuel tank. If you want to remove the whole system and just vent the top of the tank to atmosphere you can, but I kept it in place and seems to be fine how I did it.

The gas cap has a seal, so it doesn't vent, but it will hiss letting out pressure when you open it if the car is off and the system doesn't have a way to vent pressure on the stock system. I can't remember if there is hissing now with the system vented to atmosphere, but it isn't big or louder, so that tells me the tank is venting, if not all the time, then when pressure exceeds that of the valve if it is mechanical in nature. Again, I'm not really concerned about it, as it doesn't seem to be an issue.