Transmission Crunch when Flooring Throttle

[kdbar]

Thanks for all the input guys. Yeah, I'm from Cali and fill up with 91. Would this noise I'm hearing cause any sort of damage to the engine or transmission?

[jcw99]

You can't buy 93 in your part of CA ?

[wmak]

Originally Posted by jcw99

You can't buy 93 in your part of CA ?

91 is the highest we can get in CA.

[axelo]

Puerto Rico...2013 model...done it since out of the dealer july 2012, i'm gonna tune in a couple of months because i'm tired of babying it to avoid the crunching and i'm sick of the torque dip.
I Will make a thread upon my results and changes done. Wish me luck. The car is great really, and apart all the quirks, noises and lack power ... its my dream car, i just feel i have to finish the job scion left me when i bought it.

[pantdino]

Originally Posted by JB86'd

No, that's the definition of tip-in knock..when load changes rapidly and timing is too much/afr is too lean..as I understand at least. I bet your dealer put 87 in your car. Don't bother with octane booster, just drive it easy and burn off this tank and fill up with some good 91. If it's knock I bet it will go away by your 3rd tank.

This could also be a symptom of "lugging"-- being in too high a gear for the engine speed. Timing is determined by engine speed and throttle position. When you increase throttle the timing advances. If you are in too high a gear (too low revs for the speed you are going) you will get pinging / knocking until the knock sensor cuts the timing back a bit.


My car is an automatic and I have never heard pinging on 91 gas because the tranny immediately downshifts when I give enough throttle to make the car accelerate. One advantage of automatics.


It takes a LOT of knocking to damage an engine, but eventually, yes, it will.

[pantdino]

Originally Posted by kdbar

Hey All,

Not sure if this is an actual problem or not, but I've been able to reproduce it pretty easily.

Here are the steps:

1. Be in any gear (preferably 3+)
2. Coast in the gear with no throttle at all.
3. Apply somewhat good pressure to the gas ( you don't have to floor it, but a nice kick to it to up the revs quickly)
4. For about a half second, I hear a crunching sound which then goes away immediately.
5. You can repeat the coasting with no gas and then give it gas to hear the sound again.

Is this normal or should I bring it in to the dealership?

I've notice the sound doesn't happen when I apply throttle gently or normally. It only happens when I want to pick up the revs fast.

Thanks for helping me get this off my conscience!

Do you have an automatic or a manual?
If you have a manual the only way to get the revs up quickly is to downshift

[Nozag]

My car do it to. I use 91, 93 and also try octane 130 from sinto racing, and this sound still there.

This sound occur only when the car is engage on any gears, cluth in or not. I cant reproduce this sound in neutral at all.

I hate this, i ear it every time i rev match or throtle blips. Hope toyota or subaru can fix this before mu waranty is over.

[wmak]

Had my first fill-up after dealer gas was used up. Sound is still there. On another note, found another thread that has the "crunch" sound. From what a few people mention, it's throttle related and not tip in knock. I'll probably still take it into the dealer after break-in and my registration stuff gets done with.

http://www.ft86club.com/forums/showthread.php?t=67295