Evap pump noise normal?

Only had my truck 2 weeks, so this may be normal and I’ve just never experienced it. I walked out into my garage this evening to hear a loud buzzing noise from under the rear of my truck. I crawled under and felt around for anything vibrating...traced it to what I think was some kind of evap pump. I unscrewed the gas cap and there was a decent release of pressure and the pump/noise stopped immediately. Truck had been sitting for 6+ hours, and has 1/4 tank of gas.

Is this normal behavior and I just have never caught it in the act?

 

Yup, perfectly normal

 

Yup Normal.





Later thread

 

Thanks guys. In all the cars I’ve ever owned I’ve never actually heard the pump. Weird.

 

This is 100% normal and like you mentioned, the system is purging pressure from the fuel lines.

 

If you think your taco is making weird sounds late at night you ought to heard my wife’s Prius. First night we brought it home I thought the damn thing was possessed!

 

We really need to mess with the next guy that asks if the evap test is normal. Not enough to send them running back to the dealership or anything, but more like carrying out a elaborate hoax which sends them on a wild goose chase looking for the cause...

Only to lead right to the glove box where the owners manual is.

 

I've had my truck 3.5 years and I've still never heard it but know its normality I ever do.

 

Problem is this is clearly in the manual so you’d get found out.

 

Here you go. From the manual.