Diablosport Forums

I've been using the 87 octane tune for a while now and am still getting valve ping when going up hills. I have a 2008 Silverado 5.3l with DOD disabled. I am using Mobil gas and have put lucas injector cleaner in my tank to see if that helps but it didn't. Also last time I filled up, I used 89 octane but the pinging is still there. Anything I can do other than going back to stock tune?

have you logged it to verify it is actual knock?

No, not yet. I will try to do that tomorrow. I have to work tonight.

I created a log on my way to work. Not sure if it will be a good one though since I am currently running 89 octane. Also it was in a lot of stop and go traffic and it was raining. I couldn't hear the valves either. Not sure what to make of the log but I will post it incase you want to look at it.

Thanks

I ran 2 logs through DSLogRedux and both times it said to reduce injector slope to -5. So, I did that today. We'll see how it does and I'll post back.

Is it just in my head or am I really watching my gas gauge drop as I drive? Lol, is it normal to use that much more fuel when I set the injector slope -5?

Okay, I filled up with 87 octane. Truck is broke in with the injector slope adjustment. I took another log and checked it with dslogredux. It now recommends going -2.
What do I look for in my logs to check for spark knock and how much is bad? Is this the valve pinging I hear occasionally? Could I modify the tune and cut the timing back a little and would that help? Trying to learn as much as I can, any advice would be appreciated. Thanks!

Make sure you are logging Knock Retark (KR), Timing/Spark Advance, and Total Knock Spark Retard along with RPM and throttle position. I am running the 87 tune on my 2012 Silverado 5.3 and I am seeing KR at WOT and can hear the pinging. I've pulled 2* of WOT timing and it's still there. I want to run a different brand gas before I reflash again. My LTFT's are staying good, unlike yours.

rebelman06 wrote:Make sure you are logging Knock Retark (KR), Timing/Spark Advance, and Total Knock Spark Retard along with RPM and throttle position. I am running the 87 tune on my 2012 Silverado 5.3 and I am seeing KR at WOT and can hear the pinging. I've pulled 2* of WOT timing and it's still there. I want to run a different brand gas before I reflash again. My LTFT's are staying good, unlike yours.

Thanks for the reply! I have a short log I did today with those parameters in it. How much knock retard is bad? There are several times it gets to 6 degrees. I'll post the log incase anyone wants to take a look.

thanks!

I've been told you want 0 KR at WOT. I am seeing up to 6* as well. My plan right now is to try better gas and keep turning WOT timing down till it goes away.