87 tune spark knock

[06MonteSS]

if you had to adjust the injector slope that much, then you are running pretty dang lean from an air leak or leaks somewhere.. or MAF sensor issue.. which can all cause knock..

get a can of CRC Mass Airflow Sensor Cleaner and clean your maf sensor.. make sure you reinstall it facing the correct direction - the arrow on it should be pointing towards the engine/throttle body..

check air intake, exhaust connections, etc, make sure there are no air leaks anywhere..

make sure no air leaks around the intake manifold or exhaust manifolds...

make sure plugs and wires are good...

And Make sure you are using GOOD gas, it makes a difference... mobil, exxon, sunoco, amoco, bp, chevron are best brands to use, with mobil and exxon being the best..

NEVER use Shell, costco/bj's, mom-n-pop, or no-name brands, as it's crap gas that tends to cause a lot of knock retard and less performance/mpg...

[Murphy406]

I finally got around to checking all of the suggestions. I am clueless. Using advanced mode to select DOD removal and 87 tune and it spark knocks like crazy. I can't even get close to WOT. Otherwise everything runs fine. As of now I am just running stock tune with the DOD delete, firm shift, and corrected tire size for my tires.

[mikel]

does it knock on the stock tune?

[Silverado05]

Mine knocked hard under WOT and would pull timing and it ended up being rusted up knock sensors... just a thought. After I switched mine out I never had any more knock/timing pulled

[Murphy406]

It has a little knock with the stock tune. Not near as much as with the 87 tune. I will check the knock sensors. Hopefully that is it. Thanks for the info. I will report back when I have the time to do this.

[Murphy406]

Knock sensors replaced. No change. I have a 99 Sierra that I have the Predator programmer on. I followed a guide on setting the fuel under WOT and while cruising down the highway. I have never had an issue with it. I can buy gas from anywhere in town and it has little if any spark knock. I use the same gas in my 08 and the spark knock is audible. I checked the spark plugs on both trucks and they look the same. I am not sure if I don't like the 08 Silverado or the intune i2...

[Murphy406]

So. I decided to pull my engine apart. I had a little oil consumption issues and I had some valvetrain ticking that had started right after the spark knocking began. I had a few of the springs on the AFM lifters that were collapsed and the rear intake bolts were not tight at all. I pulled the engine this past August and did the DOD delete. I am now running the 87 tune with no spark knock and it make a considerable difference in how this truck runs. I guess I shouldn't have questioned the tune as much as I did. Looks like mine was all mechanical issues. It also would seem like Lew was correct with the air leak. Thanks for making me keep searching otherwise I would have just kept driving it with the stock tune.

[06MonteSS]

glad to hear it man! yeah, they tend to run much better with no air leaks and no failed internal parts good finds man!!

[Murphy406]

I ran the truck for about 500 miles since I fixed all my mechanical issues. I did a few logs and it looks like my LTFT Bank 1 is at 9 at about 1800ish rpm and the LTFT Bank 2 is at 8. This is about 65 miles per hour I believe. I haven't had a chance to hold it at that speed very long due to traffic. So I checked it when I was able to hold the speed for a few minutes. I was just glancing at it as I can't view the logs right now. I am having software issues. Anyway. On my 99 sierra I only had to make changes at around -3 or so to get it in the window recommended. I don't hear any knock and the truck runs good other than my mpg has dropped a little. Is it normal to make that much of an adjustment? I used all new gaskets and torqued everything properly. I don't think I have any vacuum leaks but I won't say that I don't. I did have to install a new cam to remove the dod so the cam is not stock. It is actually smaller than the factory cam. Will that cause an issue?