Tip In Knock?!

[ermax]

I just dropped the K00C transient retard table into my B01C rom and the ping has completely gone away. I will hold off final judgement until I get more miles on it. This car takes for ever to settle in after a flash so we will see.

Before I changed that table I did a log along with an audio recording on my iPhone. I started the recording and marked the start point with my defrost switch. So I should be able to line the data up perfectly with the data log. I haven’t played it back yet so I’m not sure if you can even hear the pinging. After a get some miles on this new flash I will do another log/audio recording to show the contrast.

Edit: I just played back the recording and you can faintly hear it. I was simply oscillating between 3500 and 2500 with the clutch in. There are a few of them where you can clearly pick it up in the recording. Tomorrow I will try to pair it up with the data somehow.

[ermax]

Originally Posted by guybo

A knock sensor will pick up a knock WAY before you can hear it. By the time you hear a knock your engine is pretty much fucked, which is why the piezo speakers that are knock sensors pick up any knock well before your ears can.

That noise isn't knock.

You make it sound like you engine is going to fly apart with a rod through the block if the knock is audible to the human ear. Have you never driven cars that dated back before knock sensors? If you bogged them they would ping like crazy but the engine doesn’t fly apart and the ECU had no way of correcting without the sensor.

Again, knock sensors are far from perfect. On the flip side you can have a rod bearing on its way out and the knock sensor thinks it’s detonating so it retards the crap out of the timing so much the car stops pulling. The knock sensor is bolted to the block. It picks up so much sound. It’s amazing it doesn’t retard the timing at random all the time.

[guybo]

This is not a 1979 Chevy with 9:1 compression ratio. Modern engines especially high compression engines like the FA20 don't take well to knock. That's not tip in knock the OP has and any knock is bad. If you can hear it, your engine is fucked already.

[ermax]

High compression ratios just means it’s more susceptible to knock. It doesn’t make it any more or less harmful to the engine. Knock on an old car is no different than a new car. You know what is actually happening when an engine knocks right?

[ermax]

Just a follow up. I am well past the learning phase after flashing. I also have an autox in on the car after the flash and the knock on shifts is still gone. Seems like the 2017 transient ignition retard table did the trick. I actually came across another thread about tip in knock on shifts also being solved with the 2017 transient ignition retard table. So that makes three threads on this topic all solved the same way now. Throttle response does seem impacted but not too bad. I am tempted to dial back the retard a little and see if I can find a happy medium where I eliminate the knock but don't hurt throttle response as much.