Stock 18' Sierra Denali 6.2l with KR..

Hi, I have not used HPT since Gen3 so I am rusty and novice. That being said I bought HPT because I wasn't happy with my brand new truck falling on its face during somewhat light throttle. After logging I see that is is KR that is pulling timing in my felt trouble area. This seems strange to me that a brand new truck running 91 octane would be showing KR without any spark modifications. This being said This is the first GenV I have looked at and the hardware and software has changed a little bit.
I will be adding some parameters to scanner to try and help identify what is going on as a next step but any advice would be greatly appreciated.

Attachment 96010Attachment 96010Attachment 96011

* Had to shorten log file to attach it...

My 5.3 had knock from the get go, doesn't surprise me that you are seeing a bit of knock on your truck.

Easy things to do are to adjust some of the power enrichment settings so it can happen sooner. Remove some of the delays and if you want smooth out the commanded eq ratio for fueling at WOT. Shoot for 12.5ish AFR or .85 lambda. Pull a few degrees of timing out and see if it calms down.

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Originally Posted by 5FDP

My 5.3 had knock from the get go, doesn't surprise me that you are seeing a bit of knock on your truck.

Easy things to do are to adjust some of the power enrichment settings so it can happen sooner. Remove some of the delays and if you want smooth out the commanded eq ratio for fueling at WOT. Shoot for 12.5ish AFR or .85 lambda. Pull a few degrees of timing out and see if it calms down.

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Thanks, I?ll start there

was looking at ur file the only thing that stands out that i?ve never seen or heard of anyone changing is your max fuel pressure under fuel sys-fuel pressure tab, compared to a stock 6.2 and all years of genv 5.3 also, yours doesn?t taper like the rest of them so maybe to much fuel?? causing a little knock,

I just looked at it, that table was maxed out from the factory. I installed my WB last weekend and pulled some data that I?ll post in a bit

odd but there is no other 6.2 or 5.3 like that i would change that to begin with, sounds good i?m the furthest thing from a tuner as i just started dabbling in this stuff but i like to learn and help where i can, for example paid 100 for a guy to tune over email by logs my sierra and after crazy knock retard and fuel mileage plummeted it took me to figure out the problem . he turned on power enrichment at 21% throttle latterly could watch instant mpg go from 17 to 10 with hardly any throttle change , that guy probly in the long run did more damage than good , there is other stuff also but i won?t go into that

Here is the current log with the wideband installed...Attachment 96244Chase 2018 Sierra Denali 01.29.20_shortened.hpl

I am out of ideas other than just working through the tuning steps to dial in air/fuel and timing....

It is a normal issue on those engines, the 5.3 and the 6.2 both knock on 91 from the factory. My 2016 6.2/A8 knocks as well. They really need 93 octane, but you can also add some E85 to the 91 mix to help control the detonation as well.

definitely not as much knock as the last file , did u change the max pressure

Where is the wideband installed?

It hardly moves at all under part throttle in the log and is pretty slow to react at full throttle. Is it installed behind the cats??

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Originally Posted by 5FDP

Where is the wideband installed?
It hardly moves at all under part throttle in the log and is pretty slow to react at full throttle. Is it installed behind the cats??

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It is behind the cat for now

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Originally Posted by 4102sierra

definitely not as much knock as the last file , did u change the max pressure

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The only thing I did was disable flex and lower the minimum ethanol to zero to see what affect it had. I haven?t touched the pressure yet but I will.

The data you gather won't be that accurate with the current placement, so I wouldn't do any fuel related tuning until it's installed before the cat.

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Originally Posted by 5FDP

The data you gather won't be that accurate with the current placement, so I wouldn't do any fuel related tuning until it's installed before the cat.

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How do shops tune with the tailpipe clamp & LC-2 if that?s the case?

on vehicles with no cats.

If the sniffer is at the back like that, it's only somewhat close at wide open throttle. Most shops have likely taken into account that their wideband reads a different value than what it really is before the cat. Like 12.8 after the cat is really 12.4-12.5 before it.

And part throttle tuning is useless with an after the cat wideband, the cat itself will skew all your data and make it junk.

Quote:

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Originally Posted by 5FDP

If the sniffer is at the back like that, it's only somewhat close at wide open throttle. Most shops have likely taken into account that their wideband reads a different value than what it really is before the cat. Like 12.8 after the cat is really 12.4-12.5 before it.

And part throttle tuning is useless with an after the cat wideband, the cat itself will skew all your data and make it junk.

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Makes sense, mine is sluggish