Evap leak.....

Any one have an issue with the filler neck leaking up top out of the 3 holes???

 

I'm not seeing any holes but there shouldn't be ANY holes in the filler neck other than where the gas cap goes.

 

These holes....

 

Those don't look factory, looks to me like someone screwed some screws or drilled somewhere they shouldn't have.

 

That pic was taken off the internet and it has the same holes that mine does

 

I don't know I still don't think there should be holes there, I'll have to look at mine tomorrow maybe someone else can chime in in the meantime.

 

Im not sure but it could be like a overflow holes. I know from experience not to push extra gas into the tank . When the pump stops you can maybe give it a little squeeze and thats it. The extra gas and vapors can really screw up your evap system

 

I’m not really sure what they are for but I have smoke coming out of them when I put it on the smoke machine.....

 

Did this ever get resolved? I have CEL’s P0442 and P0446 on a 2004 Tacoma. I was under the bed looking around at hoses and vsv when I noticed these holes on my filler neck.

 

You need to close the vent valve when doing a smoke check or it will smoke out of the gas cap like that.

It's just a drain for fuel, it doesnt seal from those holes.

 

Those holes are supposed to be there from the factory.

 

Bishop84, can you explain what is the process of "close the vent valve". Thanks and God Bless

 

There is no vent valve on Toyota LDP systems that seals the system like you would see on a conventional EVAP system even though it is called a vent valve.

To seal a Toyota LDP system like what 2nd and 3rd gen Tacomas have you have to disconnect the hose that runs from the Leak Detection Pump/Charcoal Canister to the secondary filter and block the port on the canister then tee in your smoke machine at the purge valve by the engine.

 

How does this system run leak checks on its own? The computer can’t disconnect a hose and plug it. It must have some internal vent valve, as it needs a path for vapors to release when the engine is not running and also be able close it to seal it up for leak testing which it does routinely. Im confused. Maybe you are just talking about setup for manual smoke or pressure testing.

 

Thanks for the detail here. THis makes more sense. Just couldn't see how an evap system could work without a vent valve.

 

That's mainly what I was talking about, it's not clear to me exacly how the vent valve works but I do know it does not fully seal the system when commanded on so relying on it to do a smoke test would result in a false positive leak.

I misdiagnosed one because of me not understanding this at the time, I've since better familiarized myself with how the system works.
I still don't fully understand it but I do know that the only way to fully seal the system for a smoke test is to block off the vent line.