First turbo motor, knock retard gremlins

[LoganW]

Im at my wits end on this one nearly pulling my hair out. Ill start with the vehicle and the problem and go from there.

2004 sierra 5.3, 'built' 4l60e
-Stock motor
-gapped rings
-head studs
-FIC 650cc injectors
-electric fans
-aem wideband
-on 3 7875
-china bov & wg
-homemade hot side kit from stock exhaust parts

Basically from the beginning of the tuning process Ive been fighting the vehicle seeing knock and pulling tons of timing. To better describe the problem. The engine pulls hard and clean if I hit the throttle hard. If at any point I roll into the throttle it starts to surge and buck as the motor pulls timing. This makes practical driving and using it as a truck pretty useless.

Ive been having a very reputable shop tune it on a dyno here in southern Idaho. Initially when it happened I did have some spark plug wires not fully seated so I pulled the plugs to double check their gap (all set to .027) and replaced all 8 plug wires with new ones. After that the knock didnt go away so the tuner suggested I replace my injectors. He isnt a fan of anything not name brand and I had some refurbished deka 80s. I pulled the Injectors and had them flow tested at another shop which did show several of them to be 5-7% off. I got a refund for those and ordered a set of Fuel injection clinic 650cc's. During this process I had actually hurt the motor from a boost spike. Lots of blowby resulted in me pulling the motor and replacing 3 pistons with broken ring lands. With the new pistons came a full set of new rings gapped to .026 and I added hardened push rods and head studs. While the motor was out I replaced the knock sensors with AC Delco units and replaced the harness. Got the motor back in and trailered it once again to the dyno. Now the truck is idling better and is able to make clean pulls. On the dyno it did 520 hp 630 ft. lbs at 13 lbs of boost. I was pretty happy about that until my tuner told me that the knock problem is still there. I asked him if he would turn off the knock sensors to see what the motor did on a roll in and the power curve is very choppy until about 3000 rpms where it cleaned up. Ill add a picture of both dyno graphs. Next I got the truck home because I cant afford his rate to diagnose problems. After I got it home I met up with a buddy with his tech 2 to see what the computer would tell us. We drove the truck to the local airport and put 10 gallons of 100 octane av gas. The best fuel I can get here is 91 or 110 sonoco at $9 a gallon . Even with the higher octane the knock retard was still there. We even tried unplugging the knock sensors to see what would happen and you guessed it, still pulls timing. Ive read and read all I can find on the subject and everything I try doesnt do much to fix it.

I decided that I wasnt going to pay the tuner any more money just for him to tell me that Ill have to come back another time to have it tuned again so the plan is to begin the learning process of hp tuners and start to figure this out more on my own. I logged two pulls, one at WOT and the other rolling into the throttle so Ill attach those as well as a copy of my tune. I appreciate anyone giving their .02 cents in helping me figure this out. Thanks in advance

[5FDP]

That is one terrible looking VE table, seems like he doesn't really know what he is doing there. No vehicle requires 20% more fuel at less rpm/kpa than they do at full tilt going wide open throttle. Possibly why it's carrying a 12% and 16% long term fuel trims over into power/boost enrichment on that one log. The dynamic airflow high rpm disable should set to to 7,000rpm and not 700rpm too.

Or there is a issue with the injector data or fuel pressure you are running. If I did this crude math right, 650cc is like 61-62lb/hr. If those are rated at 43.5psi they only get up to 70-72lb/hr at 58psi. Your tune has them way up around 85lb/hr so that is all wrong.

I always see those knock spikes when a knock sensor has a pending or current trouble code, it spikes to the max value in the tune at 8 degrees.

I'd say you have a couple issues you need to fix first then back to tuning.

[LoganW]

Thanks for the quick reply!
The honest trouble with the situation is I am so green when it comes to tuning so I just swipe the magic money card and hope he does a professional job. I am able to make adjustments myself and re-flash my tune. I'm eager to learn so on top of the knock thing if anyone has any places to start reading or videos on tuning to watch id love to hear it.

We tested fuel pressure and it does stay right around 58-60 PSI.
The only trouble code im getting is the P0102 for the MAF circuit. According to the guy who did the base tune, it needs that code in order to switch into speed density. Is that correct?

You mention several issues to fix first, do you mean mechanical issues? Im all up for suggestions

[5FDP]

Most of it is tune related and some might be mechanical if you do indeed need address those knock sensors themselves.

I would get the FIC injector data and input that into the tune. It should come with injector flow rate, short pulse adder, min injector pulse and offset vs volts data. Those are 4 main tables that are changed for injector information in the tune.

I'd personally start over with the VE table. Easy for me to say and maybe not easy for something that's never done this before. I'm not sure I could teach you anything as it's all really hands on stuff that takes a long time to learn. There are a few guys on here that are really good remote tuners but that will likely mean spending more money to get this all right.

[kingtal0n]

IMO If you are serious about tuning start by learning how carburetors and mechanical advance distributors work, the basic fundamentals of non-computer controlled engines, will teach you about timing and air fuel ratio requirements. There are hundreds of books from the 80's and 90's about that stuff to read.


Then, get your head in the computer game by going to the major Stand-alone ECU manufacturers websites (Haltech, AEM, Motec, Megasquirt, etc...) And download their Manuals.
Then read those manuals, read every page like a novel and then read the next one. Those manuals combined teach almost everything there is to know about computer controlled tuning applications.

All computers work the same so all the manuals will teach you the same fundamental basics which you can then apply to this (HPtuners) Style of tuning, which is both more simple and more advanced than any stand-alone out there, some aspects you can directly apply and some won't make sense unless you've experienced stand-alone tuning first.

[LoganW]

Thanks for the advice, im starting to become more familiar with how HP tuners works in general but I am far far from understanding the limits of timing and AFR

Im also realizing that this thread got off to a bad start from the start...lol. After all your replies I became a little suspicious about the tune I posted, It was sent to me via email from my tuner. I dont know if it was an honest mistake or the guy simply not wanting me to figure this out. Either way I ended up pulling the tune that was actually on my vehicle and sure enough, it was nothing like what I originally posted. Ill post the actual one and id love to hear if anything in the VE tables is significantly off.

Now as far as the original problem with knock retard goes. I have been playing around with some different things. I have a good friend with a turbo pickup very similar to mine, he just has a 5.7 with a cam and water meth. I compared what I have vs. what his is. I adjusted some of my power enrichment settings to match his. I changed the ramp in from 1.000 to 4.000 and the boost enrichment from 105 kpa to 95 kpa. That did help quite a bit. It will still hit the max knock retard on some roll ins but not every time and the surging/scratching noise I had been hearing and feeling is very minimized. Id like to minimize it even more, any recommendations on what I aught to try next?
[ATTACH]104508

[5FDP]

The injector data and VE stuff is still wrong.

[Ben Charles]

Injector settings will make or break you.. you’ll chase your tail to no end!!!