rel3rd

iTrader: (43)

2008 Silverado, 63,000 miles, 5.3, 4L60E, 3.73, NON Flex Fuel, with AFM, seems to run very well, but shows a LOT of KR at random times all over the datalogs

My old 2002 5.3 Silverado (same drivetrain numbers) allowed a good amount of timing before any hint of KR, was tuned for towing and 87 octane.

I thought a log I took yesterday (first one for this vehicle), was showing false knock, and of course it's a tad too large to attach here, so this morning, took another log, halfway to work, with 87 octane, then filled (1/2 tank to fill), with 93 octane, to see if KR disappeared, or minimized.

If anything, it showed more often KR.

I bought the truck from the original, older owner, so highly doubt there's ever been any "tuning" done to it.

I just don't get why there is so much KR?

Can anyone shed any light, or point me in the right direction?

Not asking for a free tune. I just have never seen so much KR on a stock vehicle, and am hoping someone with more experience than I, can take a look and offer an opinion.

LOG 111111 is 87 octane

LOG 222222 is 93 octane (mixed w/half tank 87)

p.s.
Pay no attention to WIDEBAND reading. Just got the truck and wideband is showing it's DEFAULT, since it is not connected yet.

brandon6.0

iTrader: (32)

Possibly bad knock sensors.

Also on all my truck tunes i disable burst knock. It will show up the same. Basicly the ecu is antisipating knock so it pulls timing to be safe. Just disable it and see what it does.

98CayenneT/A

With fear of sounding dumb..... what about excessive carbon build up?

LLLosingit

iTrader: (4)

Not dumb at all, That's one of the first things that popped in my head to, With only 60,000 I wouldn't think it would have that much carbon built up, That and todays fuels are cleaner.

gametech

iTrader: (1)

Are you sure it is real KR, or "burst KR"? Real knock retard happens when the sensors detect actual knock, but burst knock retard can show up when the computer program is set to prevent knock. some of the truck tunes are very conservative in this regard, and will kill timing preemptively, no matter the real knock status.
edit- Unless you specifically set your scanner to show the difference, any KR will read, whether real or computer imagined.

rel3rd

iTrader: (43)

Hopefully, I disabled it correctly...
I zeroed out all retard in the BASE vs. CYL AIR DELTA section

That was actually my very first assumption...Truck has low miles and was owned by an old man. I did put some injector cleaner in the tank, but may go all in, and do the SeaFoam smoke party. I am leaning moreso towards carbon due to the truck seeming to run better and better as I flog it.

I have Burst Knock Retard scanned (and attached), but not 100% sure what I am looking for...

I also screenshotted, Knock Retard, Burst Knock, and Knock Learn Factor

This is a log with 100% STOCK GM TUNE, with only mod being DoD DISABLED.

98CayenneT/A

Here is a good chamber cleaner.
http://Genuine Chrysler Accessories ..._l3JhDb6C02P1P

rel3rd

iTrader: (43)

Link doesn't seem to be working?

98CayenneT/A

Google Chrysler combustion chamber cleaner.

G Atsma

Berryman's Chemtool B-12 works pretty well too.

rel3rd

iTrader: (43)

Thanks guys. Ordered the Chrysler stuff from Amazon. Should be here Sunday

brandon6.0

iTrader: (32)

So it picked up some bust knock with it disabled. Take the one table and max it out to .8grams
Cant think of the table its above the table u set to zero's.

When i get on my tablet ill take a look at your tune.

rel3rd

iTrader: (43)

Here;s is the page that had Burst Knock settings.

brandon6.0

iTrader: (32)

Base vs Cyl delta table. Max it out.

all the multipliers below it set them to zero.


Have u checked and made sure there is nothing hitting under the truck that would make the knock sensors go crazy? Like exhaust, motor mounts, driveshaft etc. Ive seen stuff like tht make them go crazy

Darth_V8r

iTrader: (4)

What do your fuel trims look like? You could just simply be lean

brandon6.0

iTrader: (32)

Very True!

rel3rd

iTrader: (43)

They were pretty close, but have only had the truck a week and haven't put my wideband in it yet.

Heck, I cant even figure out how to make a change to the VE table since I can't find it in the tune, lol

I noticed yesterday it logged like 2 degrees KR pulling out of my driveway...no load, no quick throttle...weird, and if someone can share where the eff the VE table is, please do...

I havent had it on a lift yet to see if some wwutd rattle is happening

brandon6.0

iTrader: (32)

Most stock tunes show alot of KR. Once u get a pretty good grasp on the tuning it will all fall in line.

NicD

iTrader: (7)

Oh boy, Gen4 is very different than Gen3 so start reading. 87 octane will almost always make those gen trucks ping with their higher compression, etc. I almost always recommend people run 91 octane if they don't want it to head straight to the lower octane timing table with the knock learn factor.

rel3rd

iTrader: (43)

It has gotten quite a bit better with just the burst knock disabled. Now I am seeing 1 or 2 degrees KR instead of 6 or 8...

I wish I would have known about this year truck not liking 87. It probably would have finished steering me towards a diesel, since I do tow fairly regularly.

I know a place called DSX tuning sells a flex fuel conversion kit. A friend of mine did it to his truck and runs a 50/50 mix of E85 and unleaded. Dont know if the headaches involved with that whole deal outweigh running 93 all the time, but I guess if I have ti run it, I have to run it. I'm at about a third of a tank now, so HOPE that straight 93 eliminates the KR without having to keep dicking around with a stock truck