Knock issue

[Adam88]

Hi All,

I'm experience knock on my stock tune, and my stock tune with just torque management disabled. Do I need to lower my knock sensor down a bit and if so is there a how-to on that here? I looked around but was unsuccessful trying to find one.

I always run 91 (California gas), I've tried filling at 3 different gas stations over the course of four tanks in a row per station. I tried running an octane booster. Nothing really affected the amount of knock I am getting. When my clutch pedal isn't pushed in, like at a light, or in gear, I do get a LOT of clutch rattle. Could this be the cause of my "false" knock? If this was the case, would lowering the sensitivity on the knock sensor help out? I've uploaded a VCM Scanner file if that is of any help.

[Adam88]

I attached some pictures of the only knock sensor windows I could find. I noticed it goes up to cyl 8, when my car is a V6... 2006 pontiac g6 gtp 3.9l!

[Phantom]

First I would go back to stock do not turn off the torque management fully.
To start tuning you need to get the air flow model correct to do so you will want to scan more sensors add MAF hz, TPS, Commanded AFR, and O2 V. From there you will want to scan and create a histogram (read the help on this) that matches the MAF table but uses the LTFT and STFT for the values and add a filter to only show values when AFR commanded is 14.7. Run a scan through the histogram take the average cell value and copy it then right click and paste special multiply %half. You will do this till the fuel trims are +-3.

From what I saw the fueling is lean get that in order then see if there is less KR if so try reducing the timing in the cells with KR, if you have to lower this a lot or it does not go away there is another problem.

I almost for got make sure that the car is mechanically sound and look for something that might be hitting the block.

[BigDaddyCool]

I second the above post.

Tune the car up with torque management on first otherwise you'll just be running around in circles chasing your tail.

Been there done that

[Adam88]

Thanks for the advice, will definitely do that!! So glad I save all my tunes to many places, stolen laptop ftl, but backup's of everything ftw!!

[Adam88]

"reducing the timing in the cells with KR, if you have to lower this a lot or it does not go away there is another problem."

I've reduced the timing in those cells -15 and still get the same amount of knock. Just did plugs, wires, sea foam, oil which has always been done between 2500 and 4000 miles with full synthetic. The only thing I can think of is I get really bad clutch rattle when my clutch isn't engaged. At this point if I'm running lean, I might just bite the bullet and take it in for a dyno tune. Better safe then sorry IMO. Maybe they will let me watch what they do so I can learn as they do my car.

[Phantom]

Look for lose exhaust brackets, worn motor mounts that could be causing false knock.

Can you post your stock and current tune also post the config file you are using and a new scan if you have one. That way we can see where you are now.

[Adam88]

Here is my stock tune and a stock log and my current config file. I do have motor mount issues actually, currently have my motor mount inserts on order but they will take 4-6 weeks. Car has a k&n cone/heat shield kit with just a resonator delete.

[Phantom]

Get the motor mount fixed and see if the problem goes away. You might want to scan for some trans sensors just to see if there is any relation. Attached is my current config for my 3800 SII NA, it might give you some ideas.

[BigDaddyCool]

LTFT is lean ... bring your fueling inline, it'll help lower the engine/intake temps somewhat and then look at the knock again.

Try adjusting your MAP/MAF on the area of knock to report more air to for the ecu to compensate by adding more fuel....... otherwise try the other direction and lean those spots out if they are already slightly rich.

Try and error, but LTFT is lean... so probably start there, and if you dont have one, get a wideband rigged up (helps alot)