08 Sierra Denali spark knock

[shrecewa]

I've been reading the forum for some insight to this problem...but didn't see anything specific.

I've got an '08 GMC Sierra Denali. I purchased the 7194 predator about a month ago...and installed the performance tune. I notice that I get some spark knock @ WOT. I have always run Exxon 93 octane, from the day I drove off the lot...until I read some posts about gas. I've tried two tanks of Amoco 93, with the same result. I plugged in the predator and watched the knock retard parameter some (hard to do while driving). I couldn't watch the predator all the time and I don't have a laptop to connect to make a long data file, but I did notice a couple times when I heard the spark knock that the KR was 2-3. It does not consistently knock and sometimes it the knocking is worse than others. I've reprogrammed the truck with the stock tune. The tool has 8r10 revision installed. Any suggestions for where I can start. I've had 3 other predators for various vehicles with no problems, so I never looked into making any adjustments to them. Thanks in advance for your input!!

[06MonteSS]

you HEARD the knock/ping and it was only 2 or 3 degrees of KR??

hmmm.... I've seen up to 7 or 8 degrees of KR and still haven't been able to "hear" it...

with the stock/original tune in the truck now, have you logged/viewed the real time data to see if you're getting the KR with the stock/original tune??

[shrecewa]

With the stock tune installed, I didn't notice any change in the KR reading @ WOT. The spark knock is not loud, but with the radio off and the fan on low, I can hear what I'm assuming is some knocking. What parameters should I monitor? The log will take a few minutes of just a few parameters. There is no other indication of any KR or spark knock under any other driving conditions, that I've found so far. I have approx 6000 miles on the truck, now. I did install and run the 87 octane tune. I didn't get any KR or spark knock with it.

I forgot to mention in my original post that the truck is stock with 1 addition. I purchased the GM performance cold air intake and had the dealership install prior to delivery.

[06MonteSS]

aaaah...

log your long term fuel trims - bank 1 AND bank 2...

do the log at steady driving/cruise at about 2k-2500 rpm.... going about 60 mph... if that is a 4 speed auto, put it in 3 and do the log....

sounds like we need to get your fueling adjusted correctly...

[Sniper]

shrecewa, borrow a laptop and log as Monte has suggested. Then, download the DSLogRedux program and get your LTFT's in line. I only run 93-octane Amoco in my '08 SD and I was also getting the dreaded knocking during my WOT runs. Don't touch your PE until your LTFT's are in line. Once the program tells you your LTFT's are okay, THEN check the program's recommendations in the PE section and modify them. It's easy and you will notice a big difference between the Diablo program and your newly modified tune once your LTFT's are correct and your PE is altered.

The only thing left to do after you tweak your settings will be to play with the TCM settings, but the update is still not out for us to be able to do so.

Good luck to you!

P.S. - As you already know, the SD's have a 6-speed transmission. When logging I would put my truck in manual mode, lock it in 4th gear, set my cruise control when my tach would read somewhere near 2,500RPM (from memory, around 60MPH) and record my log. Within that log, I'd punch it a couple of times to get my WOT data logged, as well. Let the Redux program do the rest. IT'S AWESOME!

[06MonteSS]

nice!! good info Sniper!! thx man!! (I don't have first-hand knowledge of the trucks)...

glad to see ya around again...

[shrecewa]

Thank you again for the info, I'll work on that this weekend... and repost. Will the DSLogRedux program guide me through setting up the LTFT's?

[Sniper]

Monte, it's the least I can do for all of the help you guys have given me!

Thank you again for the info, I'll work on that this weekend... and repost. Will the DSLogRedux program guide me through setting up the LTFT's?

The Redux program will help you set up your LTFT settings. Just remember, do NOT mess with the PE settings until your LTFT's are in line.

[shrecewa]

Gents, I installed the Diablo '93 performance tune this morning when I got to work, in preps for logging my trip home. I think I run a good log for analysis on the way home today. The DSLogRedux program reviewed my data file and suggested that I adjust my injector slope down by 10%.

So, I made that adjustment to the truck....so I can run another log tomorrow morning going to work.

This evening, I went for a short trip to the store...and jumped on it a couple times. It was very responsive (considerable difference), but I still had some spark knock. My previous log file was just steady state driving. Recommendations?

Thanks for the help...

[06MonteSS]

did you drive for 20-30 miles BEFORE you started to log any info???

need to let the tune adjustments settle in man... can't just change the tune and log - you won't get accurate data...

you also have to wait and drive until the vehicle is up to normal operating temps, usually about 20 minutes, before you begin any logging...

[shrecewa]

I didn't drive for 20-30 miles, but the engine was running about 10 minutes + about 6 minutes driving time (16 total) before logging. After reading your post, I flashed back to Diablo sport 93 default settings.... which is where I am now.

So, I need to run the engine to ensure it is up to normal operating temp, and drive for a while to ensure the tune adjustments are settled in? I just want to ensure I'm working it correctly.

I am having another problem with the data viewer. I downloaded the new version posted under the downloads section...and it tells me that I have an older revision of the tool, that it needs updated. I rebooted the computer, with no change. The new dataviewer software (rev 3.1.6.7) doesn't like my tool. I do have the 8r10 crom revision. I will have to find the older version and reinstall it to do any more logging.

[06MonteSS]

yeah, after installing tunes and making injector slope adjustments, you need to drive for about 20 miles to let things settle in...

PLUS...

the vehicle has to be up to normal operating temps before doing any logs, so that you get accurate data..

[shrecewa]

Thanks for the clarification. Once I get the dataviewer problem working... I'll get some more good logged data...hopefully within a couple days.

[shrecewa]

Absolutely... but worth the trip, from what I am reading. I'm trying to not be a 'newbie' too long, but I'm sure I'll have some more questions when I get some new data.

By the way, how much data should I take in order to have enough to base some changes?

Should I only do steady state driving or should I jump on it to see some possible changes in KR?

[06MonteSS]

to start, just do a normal driving/cruise... need to get the part throttle fueling dialed in before we worry about any WOT stuff...

fill up the log till it says "Log is full"...

the more data the better...