Wet slappy sound coming from engine at low RPMs when accelerating.

[Shinare]

So I've noticed that my Yaris is making an odd sound. I have an AT transmission and when at low RPMs I push down on the gas pedal and a "wet slappy" sound comes from the engine. Almost like wetting your lips and making a low slobbery fart sound from your mouth... (I know, its the best way I can describe it hehe) It goes away completely once the RPMs come up a little. It can happen in any gear, as long as its low RPMs and I am pressing on the gas. It seems to get worse if I barely press on the gas rather than more aggressively pressing down.

I thought it might be the ultra-cheap ethanol gas I use, so the last three tanks I've filled it from empty to full with super premium no ethanol gas. Its still doing it.

Any ideas?

[CTScott]

Does it just do it in motion or will it do it sitting as well?

[bairjo]

I would suggest that you have an assistant start the car while you stand in front of the car with the hood open. Try to locate the general vicinity of the engine compartment the sound is coming from. You may even be able to see something bubbling at a fitting or something like that.

Yaris farts...for some reason I think of some of those Yaris Sanchez photos that pop up when googling "Yaris":eyebulge:

[colj00]

possibly an exhaust leak? a video would be helpful

[Shinare]

Hey all sorry for the delay in responding. It does not seem to do it while sitting still. It seems that it only does it when under load when trying to get past the very bottom of the RPM range when giving it a little gas. After getting past that it does not make that sound at all.

I was going to say that its so subtle that I'm not sure if I could get it on video, but I was in the drive through at Micky-D's this morning and with the window open and next to the building, the sound was reflecting off the wall and it was quite noticeable when pulling up to the next (2nd) window.

I'm not sure how I would get a video of the sound if its so subtle inside the car while accelerating, but I will try today sometime.

[CTScott]

Check the axle boots for the CV joints. One may be ripped where it has a flap.

[Shinare]

OK, so after hearing it more clearly when beside McDonnalds in the drive through (sound reflecting off the side of the building) I've been trying to reproduce the sound every day as I go through the drive-through. After doing so, I think I have figured out what it is. Although from the interior of the car it sounds faint and "wet and slappy" as you might expect if you were to make a fart sound between with your mouth by blowing air between your cheek and teeth, from the outside it sounds "chirpy" and seems to be in line with what my daily belt squeal sounds like that happens when I start my car.

Yes I know that means a loose belt, and if I hadn't already tightened the darn thing 4 times to the best of my strength and a healthy pry bar on the alt, along with spraying that "no squeal" spray on the belt and pullys, I'd say you were right. But it seems no matter what I do (even buying two more of the same belt from AutoZone) it squeals. I've kinda just lived with it.

[428CobraJet]

I would suggest that you have an assistant start the car while you stand in front of the car with the hood open

I would highly recommend that said assistant and "beneficiary" not be one in the same.

[tmontague]

OK, so after hearing it more clearly when beside McDonnalds in the drive through (sound reflecting off the side of the building) I've been trying to reproduce the sound every day as I go through the drive-through. After doing so, I think I have figured out what it is. Although from the interior of the car it sounds faint and "wet and slappy" as you might expect if you were to make a fart sound between with your mouth by blowing air between your cheek and teeth, from the outside it sounds "chirpy" and seems to be in line with what my daily belt squeal sounds like that happens when I start my car.

Yes I know that means a loose belt, and if I hadn't already tightened the darn thing 4 times to the best of my strength and a healthy pry bar on the alt, along with spraying that "no squeal" spray on the belt and pullys, I'd say you were right. But it seems no matter what I do (even buying two more of the same belt from AutoZone) it squeals. I've kinda just lived with it.

There was a thread on this a few month ago where a few people had stated that certain belts tend to always squeak. They had recommended a specific belt to get that tends to not squeak. I can't remember the name of it but if anyone remembers post it here.

I just bought mine from Canadian Tire (don't remember brand) and I have had absolutely no noise from the belt at all. I realized I had over tightened it so went back and loosened it a bit to not cause premature wear on puleys. There should be roughly 3/4" deflection of the belt when pressed on (if I remember correctly)