Hello, I have a strange noise issue. This noise has been with my 1996 Tacoma 6cyl 3.4L engine since I?ve had it at 65K miles?I?m just about to hit $140K and runs great. I keep up on the maintenance with the truck very well (at least I think I do). This noise has baffled me from day one.

It only presents itself when I?m driving up to the mountains in higher elevations (I live in Southern, CA). It sounds like a ?wheezing pig? (guess that?s the best way to describe it). The wheezing sound is coming from a black box that is located in the engine compartment, on the driver?s side, from the "cylinder shape" closest to the Master Cylinder.

The wheezing sound will continue even after I turn the truck off. It?s pretty loud too, sort of embarrassing almost. The sound will continue for about 10 minutes slowly getting better.

Any ideas? Any help would greatly appreciated! Thank you

 

That's the fuel vapor recovery thingy.....seems there's a valve of some sort that likes to go bad on it....not that that is what's wrong with yours....I'm NOT a mechanic or even close.
Mine was doing it for awhile, but has stopped for some reason, nothing that I did.

 

Not to sure on this one,have you ever replaced the fuel cap?Any vaccuum lines missing,plugged,kinked,leaking?Thats the evap canister BTW.Next time try screwing the cap out a few turns to releive pressure and see if it quits.Its a cheap place to start.May not be the cap though.

 

I changed the fuel cap when I first got the truck, and I just replaced the fuel filter last weekend, I think it was the original one. Maybe that might help. I'll try the fuel cap idea...if that at least helps stop the noise. I checked all the hoses and they are all good. I'm going up to the mountains tomorrow so i'll get a chance to see if the new fuel filter helps. If not, releasing the fuel cap to stop the emabarrasing noise is a good idea. My truck does not deserve such humiliation!!!

 

Changed out the fuel cap, it did not help the noise when I was in the mountains this weekend. It was not as bad though as it has been in the past and when I stopped the truck, the noise stopped with it. Any more ideas?

 

My truck does the exact same thing just not as loud. Dont know what it is.

 

Sounds like you either have a leaking vacuum/EVAP hose or a purge valve that isn't opening correctly.

 

At least I know I'm not going crazy and am not the only one who has this annoying pig squeeling in my engine. I will check all the vac lines, Is it possible and fairly easy to replace a purge valve? i'm not even sure how to get to it. I'll have to look at the chiltons for that one. Good ideas of where to start though...thanks

 

It's a known issue that's covered (info only) by a TSB. It doesn't hurt a thing, it simply makes an annoying noise. There is a $20 fix from the dealer and it goes between the EVAP canister and the actual line (which goes to the fuel tank and relieves pressure due to temperature).

 

Christian, is that the same as the EVAP "buzzing" fix?

 

Yeup.

Like someone else said, loosening the gas cap will stop the noise until pressure in the tank builds up again (from ambient heat). Mine's done it since it was new, I only learned about the gas cap trick a couple of years ago.

 

I've never heard it described as a "wheezing pig" so that threw me off a bit.
Mine's been doing that since new, but it doesn't bother me a bit.....too lazy to fix I guess.


Here's the info if surfjimbo is so inclined:
https://www.yotatech.com/forums/f2/buzzing-noise-45575/