Tip In Knock?!

[VincentN]

I've read around about the issues of the 'Throttle tip in knock' sound that some of our cars get, but had no fix/solution to stop it from happening again.
No engine/power mods on the car, and before when it was completely stock I still had the same issue? Just wondering if there's anyone that had this issue and got it resolved. Thought my Oil Change would change it, it did for a bit then it came back.

Happens when I'm coasting then I start re-applying some throttle and it'll come and happen for a few seconds then it stops.

Went twice to double check if it was my heat shield and it isn't, so this is almost what I come to the conclusion of.

For those who need a auditory understanding, here is something almost identical to mine.
[ame="https://www.youtube.com/watch?v=g8nnFeP7ib0"]Frs/Subaru Brz "tip in knock"? and VVT sound - YouTube[/ame]

[steve99]

Hmm that doent sound like tip in knock. But you rearly need to log ecu parameteds to be sure. Detonation pre Ignition or pinging or igniion knock is usally a more high pitched tinny sound like ball bearings in a tin can.

The noise in that video sound like a mechanical noise like vvt rasp or resonance or engine bearings on the way out or low oil levels\pressure or something rattling

[ermax]

I think he is referring to the click on shifts when the throttle is reapplied. My car does this too. This video isn’t a good example. I’ve seen others post videos of this problem that sound better. On my car it without a doubt sounds like knock. I’ve been at the car thing for a long time and recognize knock.

Listen to the video again but focus more on the sound between gears and see what you think.

Maybe I will get a recording of my car today.

[ermax]

There is also a thread that I think Tor started which was about tip in knock where you pointed out that the transient ignition retard table for the 2017 roms changed. If I recall Tor took this new table and dropped it on his tune and the tip in knock sounds went away.

[SLVRSRFR]

Originally Posted by ermax

I think he is referring to the click on shifts when the throttle is reapplied. My car does this too. This video isn’t a good example. I’ve seen others post videos of this problem that sound better. On my car it without a doubt sounds like knock. I’ve been at the car thing for a long time and recognize knock.

Listen to the video again but focus more on the sound between gears and see what you think.

Maybe I will get a recording of my car today.

I have this click too and it drives me mental. Doesn't happen every single time I shift, but when it does, it bothers me to no end.

[strat61caster]

video is definitely the throttle body noise, not knock

[ermax]

I would think if it was the TB that you would hear it on every shift which you don’t. It only happens when you rush back to the throttle on a shift. I am not even talking about WOT. I’m talking about light throttle but just rushed. As long as you delay your throttle application then It will not make the pinging sound. I’ve also tried to duplicate this sound with the engine off and the TB does not make the same pinging sound that I hear on quick shifts in my car. Yes I hear the TB but it isn’t the same sound.

[BRZnut]

Isn't this the same sound posted few years ago of those that had issues with the seals going on the injectors? I can't find the video of the sound but here is a link to a long discussion of the issue (the sound may be buried in the tread)

http://www.ft86club.com/forums/showt...injector+seals

[ermax]

The seals make a popping sound kind of like a cork gun rather than a clicking/pinging sound.

[Ultramaroon]

I can reproduce tip-in knock at will in the same way that OP describes. I don't know much about what the ECU is doing except that it's waking up from fuel cut.

1. Drive for a good long period a steady highway speed.

2. Lift completely for long enough to go into fuel cut.

3. Stab at it. Doesn't take much.

Like @ermax describes, it can be avoided by applying throttle in two stages. First crack it open to wake up the injectors. Then go ham-fisted (footed?) with confidence.

[ermax]

I think a data log of the throttle position in sync with an audio recording may be handy. Do some shifts where you avoid the pinging sound and some shifts where you invoke the pinging and then you should see how the throttle is applied. You should be able to see that it isn’t rapid movement of the TB that makes the sound. It seems to be all about how quickly you get back on the throttle between shifts. Sure it’s easy to avoid but I have to drive the car unlike any other car I’ve ever driven. Who wants a sports car that you can’t do quick crisp shits without being haunted by a sound that resembles detonation so much you cringe every time.

As I said before, Tor has this sound (even linked to this same video) and he was able to resolve it with the 2017 transient restart table. It it really was just DBW making sounds then why would changes to the transient retard table have any impact on the sound?

[VincentN]

Originally Posted by ermax

I would think if it was the TB that you would hear it on every shift which you don’t. It only happens when you rush back to the throttle on a shift. I am not even talking about WOT. I’m talking about light throttle but just rushed. As long as you delay your throttle application then It will not make the pinging sound. I’ve also tried to duplicate this sound with the engine off and the TB does not make the same pinging sound that I hear on quick shifts in my car. Yes I hear the TB but it isn’t the same sound.

Exactly my situation, even in neutral and I throttle it, you'll hear a minor resemblance of the sound on the initial 'stab' at the throttle and then it goes away.

[ermax]

If you stab at idle you will also hear the intake gulp up air. If this is what you are referring to this is something else. Almost all cars do this but the 86 seems to do it more than others. It’s almost like the CPU in the ECU is underspeced for the task at hand. It seems like it doesn’t keep up with rapid changes to the throttle. It’s like the TB reacts quickly but the timing and fuel adjustments lag behind a little.

[DaBoBo21]

I've had this noise in my BRZ since I took it off the lot. It only happens on very humid/ hot days. I always thought it was the throttle body opening suddenly. Maybe it isn't.. Haven't had any issues though.