2007 Yukon Denali -- pinging with Predator Performance tune?

solutionsix · Post by **solutionsix** » Fri Oct 30, 2009 9:01 pm

I have a 2007 Yukon Denali with 59k miles that I just purchased a Predator u9174 for. When I first got the tuner it was running 9r09. I put the performance tune on while running my usual 93 octane BP gas. I definitely noticed the torque increase right off the bat, however, I also noticed some pinging at around 4000-4500 RPM. I did some reading on the forums and noted that I shouldn't be hearing audible pinging with the knock sensors doing their job, however, I definitely hear something that sounds like some rocks rattling around in a tin can (forgive the terrible analogy - and if its not pinging, any insight as to what that might be?) at WOT at about that RPM.

I then ordered the PC interface so I could update the tuner, which I did today to 9r10. I ran the performance tune again and took it out for a drive only to have similar results, however, less severe and only above 5000 RPM now.

I did some more reading and noted the typical "watch your KR" so I took it out with the real time logging on and watched the "Maximum Knock Fast Spark Retard" value which definitely began to spike (to about 1.4 to 2.0) once I started hearing "the noise" again. I havent run it all the way up in fear of any damage it may cause so I guess I'm just looking for suggestions as to what to try? The only other time I've heard this same noise is with my Superchips tuner with a 91 octane tune and 89 octane gas... I had the Cortex on my truck for a few months and decided to try the Predator after hearing many positive things from forums all over. After running 93 in the truck with the cortex I never heard that noise again.

If it is knocking, what I should try to solve it? I've run the logging with the stock tune on and watched the KR values and i see just very minor blips in KR (0.02ish) at WOT... mostly at shifts or immediately getting on the throttle. I do however see major changes and spikes in KR while just cruising at very little throttle at steady RPMs with the stock tune? It will randomly spike from 0.00 to 4.00 then count back down to 0.00 again and repeat randomly. I had read some KR at low throttle was normal but figured I'd check. Strangely enough, it doesnt do it nearly as much at low throttle with the performance tune enabled, however.

Any suggestions would be welcome, thanks!

Post by **06MonteSS** » Sat Oct 31, 2009 11:30 am

get me a normal steady driving/cruising data log, and then also a separate WOT log, and I'll check 'em out....

these are the only parameters you need to log for both logs:

air fuel ratio
commanded throttle position
engine speed
intake air temp
long term fuel trim bank 1
long term fuel trim bank 2
MAF Sensor Mass Airflow
spark advance
total knock spark retard

solutionsix · Post by **solutionsix** » Sat Oct 31, 2009 4:43 pm

Got it. I grabbed 4 of them...

Stock - Normal Cruising
Stock - WOT

Performance Tune - Normal Cruising
Performance Tune - WOT

I've attached them to this post in a zip file. Let me know if you need anything further. The stock results at WOT even look odd to me but... I'm not sure how much it is supposed to pull timing I guess in stock form at WOT -- and therefore they could look completely normal in that case

Thanks for your help.

Post by **06MonteSS** » Sat Oct 31, 2009 4:47 pm

did you put on 50-75 miles between switching from stock to diablo tune to let the fuel trims settle in and get relearned before you did the performance tune logs??

Post by **06MonteSS** » Sat Oct 31, 2009 5:11 pm

you forgot to log the commanded throttle position in the stock cruising log... but I went through it manually...

based on both cruising logs, you need to adjust your injector slope -4% from where ever you have it set at right now...

Post by **06MonteSS** » Sat Oct 31, 2009 5:19 pm

as for the WOT logs... you definitely shouldn't be "hearing" any knock... the KR is only up to 2*-3* for split seconds... definitely not enough to be causing engine noise that you can hear....

sure it's not something else?? anything loose under the truck or in the engine bay???

you definitely do not have a lot of knock that should be causing it to be audible...

and you are running rich at WOT as well... unless the truck was good and hot and the COT was kickin' in dumping in extra fuel... but you are running rich...

go -4% on your slope adjustment, then also go -4% in the PE (power enrichment) fueling settings in all rpm ranges. PE is your wot fueling table... going negative in PE will lean you out a little...

solutionsix · Post by **solutionsix** » Sat Oct 31, 2009 6:08 pm

Thanks for the quick response. I put only a few miles on between tunes so... unfortunately maybe they are invalid results due to that fact?

However, whatever the noise is, its distinct and only when the performance tune is on... best I've been able to describe it (and somebody else who rode iwth me described it the same) was "a few small rocks in a tin can" kind of sound. Just random and tinny with no real pattern to it like a knock usually has. It also sounds much higher pitched than a typical knock.

It's the exact same noise I use to get with my Cortex in my Avalanche (5.3L) if I was running too low of octane fuel in the tank and got on the throttle. I heard the same noise from my buddy's Sierra Denali when we put the Cortex on his a while back and he was running some sub-par fuel, however, once we got some higher octane run through, the sound went away. That was the only reason I was figuring it was a slight knock due to it happening previously on lower octane gas. It sounds like its coming from the lower side of the engine behind the firewall... (almost low enough to be in the front end of the exhaust honestly) and only after the tune has been applied. Regardless, I'll put the performance tune back on, give it 50 miles or so and then try the recommended settings you gave. Thanks again for your prompt response, its been very helpful thus far.

solutionsix · Post by **solutionsix** » Sat Oct 31, 2009 6:13 pm

Another note on the running rich issue. The truck should have only been average temp or lower. I know i was about 210 on the gauge when i started the tests all 4 times, however, our outside air temp is about 40 degrees today so I'd assume it would be running a little cooler than average.

Post by **06MonteSS** » Sat Oct 31, 2009 6:20 pm

what octane gas are you using with the diablo tune installed??

should be running a good brand 93 octane....

and not Shell!! heh...

solutionsix · Post by **solutionsix** » Sun Nov 01, 2009 12:08 am

Still using BP 93. I learned quickly which gas would and wouldn't work after I got the programmer for the avalanche and BP always seemed like the best option. After I had the first "issue" i tried BP 93 octane from another station just to be sure and had the same result 2 tanks later. I had hoped it was just a bad tank of gas but no luck.

Post by **06MonteSS** » Sun Nov 01, 2009 9:22 am

k... well, adjust your injector slope as I indicated above... put on 50-75 miles, then do a new log and re-check the ltft's...

and then also get on it a little to see if you still hear the knock noise you're talking about...

fadhil · Post by **fadhil** » Sun Nov 01, 2009 2:15 pm

i have 2008 Yukon Denali and i still have sound of pinging even if fall my tank with 93oct if i use performance tune thant i chose 93 oct i will hear the pinging if i chooce the other tuning there is no pinging sound also after log and the 0.0 it still the pinging

sounds like some rocks rattling around in a tin can

fadhil · Post by **fadhil** » Sun Nov 01, 2009 2:19 pm

injector & wot log

fadhil · Post by **fadhil** » Mon Nov 02, 2009 2:59 pm

fadhil · Post by **fadhil** » Wed Nov 04, 2009 4:11 am

fadhil wrote:i have 2008 Yukon Denali and i still have sound of pinging even if fall my tank with 93oct if i use performance tune thant i chose 93 oct i will hear the pinging if i chooce the other tuning there is no pinging sound also after log and the 0.0 it still the pinging

sounds like some rocks rattling around in a tin can

if i use 85 oct tunig or factor tuning no painging

but i i use preformace tuning even after I adjust the injector & wot

can please answer me what is the problem