Acceleration noise

[John W]

Our Corolla is an '01 "S" with the stock 1ZZ-FE engine. (We're the original owners, and now it has 111K miles on it.) It's been an AWESOME car as far as its reliability, but lately, it's been bugging the heck out of us with a noise we can't pinpoint.

When we accelerate from a "dead stop", it sounds like there's an exhaust leak or a vacuum leak in it. We've had our exhaust system checked over, and they didn't find any leaks. While changing the antifreeze and both radiator hoses yesterday , I looked over everything that I could think of in the intake area and didn't see anything loose or leaking there, either.

It's not a whistle of a traditional vacuum leak, and it's not a "roar" like a big exhaust leak. It's just a distinct change in tone on acceleration. If you're gentle on the throttle, you don't hear it. But if you hit it hard, it sounds like a big leak in the air cleaner housing - kind of a muted "whoosh" sound along with the normal engine noise.

Any ideas or things to check out? Thanks.

John

[Tim, Ohio]

First, have you checked out all of the air intake hose connections or
ports that might not be properly reconnected.

Second, I noticed when I replaced the serpentine tensioner
(which was causing my grumbling noice at acceleration) that
when I put a wrench on the new one and pulled it back there was
a swooshing sound, like vacuum from the tensioner. I don't know that
this would be the problem, just a similar sound. I was able to pin
point the noise and where it was coming from by having a driver
put their foot on the break, the vehicle in drive and press the
accelerator while I listened in the engine compartment. Hopefully,
someone you can trust will be in the drivers seat (chuckling).

Good luck, that's all the experience I have on this issue.

Tim, Ohio.

[01loadedLE]

Check the air filter cover also. It's very easy to believe you have it fastened properly when the back side of the cover is not held in place completely.

[Banana_Boat]

you might have the same problem i have.. if it sounds likea flappy air sound its a lean in the elbow part of your exhaust, connect to the headers and catback thing gets HOT. or just an exhaust leak

[DjiNN]

i have also a sound during acceleration which sounds like a exhaust leak.

[John W]

Thanks, everyone for your advice. I've checked for leaks around the air filter cover and around the intake air hose connections - no problems. But I've suspected the tensioner. Thanks, Tim for your input.
The weird thing that made me suspect the tensioner is that the noise is greatest when accelerating the hardest from a dead stop. Of course, the harder you accelerate, the more the tensioner's going to have to work due to the torque....

[Tim, Ohio]

John,

I replaced mine with one from Advanced Auto at a cost of
$120 including sales tax. It is not too difficult if you have
a narrow breaker bar to remove the main bolt in the center.
If not, a wrench with a pipe on the end will do it, if you can
fit it into the area. Also, when putting the belt back on, it
is just as easy to fit the belt over all of the lower pulley
areas and finish on the top where a pulley from the alternator
(I think that was what it was, it might have been the AC
compressor, can't remember) is easily accessible while you have
the tensioner is disengaged.

Good luck,

Tim