2012 5.3 silverado knocking with stock tune

[TravRMK]

I am trying to make heads or tails of this 2012 5.3. It seems to knock with the stock tune? Do you think the knock sensor is bad, or set too sensitive? It seems to only do it when you mash down on the pedal. Sometimes it is taking 7 degrees. Anyone have any Ideas? I am still learning how to use this awesome software. Thanks.

[TravRMK]

12687Here is a log of what I'm talking about

[Taz]

Trying logging GM.ETCTP (not SAE.TP_B) - this should show WOT occurring, and GM.KNKRET.

Looks like you are going WOT from a near stop, or lower RPM - and are encountering knock / burst knock.

What grade of fuel are you using ?


Regards,
Taz

[TravRMK]

87 octane at 4400ft above sea level. Is there a way to tell which timing map is active? Does it switch back and forth on the fly?

[TravRMK]

Thanks Taz, I will log those other pids tomorrow, and post back

[Taz]

Is there a way to tell which timing map is active? Does it switch back and forth on the fly?

Yes ... log E38.OCTSCL_DMA. The ECM will blend the High / Low octane tables "on the fly" - it doesn't use just one or the other.


Regards,
Taz

[slows10]

I dont see how any kind of a "guess" could be made with that pid list. Log both stft and ltft and Both bank02 sensors. As well as iat and ect. These pids are just to see if the engine is running "normal" and no obvious problems.

[Taz]

Learning how to use the Scan Tool and create logs is one the best ways to learn about the software, and how the ECM interfaces with the "hard parts" - a step many forget, or do only after things don't go well.

I'm assuming the truck is stock - given the year - and probably still under warranty. Starting off with small PID lists lets you start to develop an understanding of the process, without being overwhelmed.

You are correct, more PIDs would be necessary for tuning - and I assumed this was a learning exercise - rather than a first attempt at changes to the calibration.


Regards,
Taz

[minytrker]

87 octane at 4400ft above sea level. Is there a way to tell which timing map is active? Does it switch back and forth on the fly?

Well there are 2 of your problems. I would run better gas and then log it.

[GMPX]

It's not uncommon to see knock on a stock engine with stock tune, even at part throttle. If you want to confirm it's fuel, simple, let the tank get as low as you can then put in a tank of better grade fuel and re-log

[TravRMK]

Truck is 100% stock with 600 miles.

[slows10]

Like was said it is normal for these engines to ping some and have spark retard. Try some high octane fuel, I bet it runs better. Also are you carrying weight in thebed or towing a trailer?