2003 LQ4 6.0 1500HD Tune Help

[Pat406ci]

Hello, I am currently tuning my truck in Open Loop, Speed Density, with Wideband.
2003 1500HD 6.0 LQ4 4l80e, 3.73 gears, 33" tires.: Mods: Full Exhaust: 1 3/4" full length headers, high flow cats, 4" single catback w/ straight-through mufflers. GM high-stall converter (+/- 2,600 Stall). All else is stock.
I have tuned the PE, VE and spark table.
With my current tune, I have registered 435hp and 463lb-ft @ 4900rpm (Hp tuners Calculation).
Seems a little high for so little mods, but truck feels very good at top.
My problem is that I am getting 8 degrees of knock which usually starts around 2000rpm and from the log it looks like it starts to knock whenever the truck goes into PE mode. Its as if the switch into PE is causing the knock. No knock in the upper rpm range. When I step on it on the free-way, it doesn't knock and feels great at top. A 0-60 run will start to knock in that 2000rpm range and pull timing consistently. Any help with this would be greatly appreciated.
I will post my tune and log file as soon as I figure out how I can post it.
Thank You.

[Pat406ci]

See attached files. thanks

[blindsquirrel]

You're out of injector, which has caused you to over-inflate the VE to try and compensate, which is what's causing the too-high HP/TQ numbers, would be my guess.

This is a stock cam?

[5FDP]

If you have ANY pending or current knock sensor code it will trigger the automatic 8 degrees of timing pull or whatever value is the MAX timing pull allowed in the tune.

I can't view your log but that is likely what I suspect.

[blindsquirrel]

Yeah, it doesn't look like real knock, it just goes from zero straight to exactly 8.000 for a while then back to zero.

[Pat406ci]

Yes, it is a stock cam. Only mods are long-tube headers/free flowing exhaust.
Yes, my injectors are at 98%.
Seems like time for injector upgrade.
I wouldn't think I would max them out with only free-flowing exhaust.
Thanks guys for looking into this.

[blindsquirrel]

What's actual fuel pressure on a manual gauge, under load?

[bradleyhamlin123]

stock 6.0 injectors are only good for factory applications. many people max those out with a CAI and a tune. I would look into any codes as 5fdp stated. him and blind squirrel are extremely knowledgeable in tuning. on top of getting a minimum of 35# injectors but i would just spring for some 42# injectors so you have room for a heads/ cam build in the future.

[blindsquirrel]

A set of 35lb L59 injectors is over $600 (currently $83/ea). There are better, cheaper options.

[bradleyhamlin123]

agreed. some junkyard flex fuel injectors will suffice. im currently using some supercharged 3800 injectors that are 42lb at 58psi. those were had for $150 then cleaned and flow tested at a local speed shop for $20.

[blindsquirrel]

51lb L96: https://www.ebay.com/itm/274424906026

[horsepowerguru427]

agreed. some junkyard flex fuel injectors will suffice. im currently using some supercharged 3800 injectors that are 42lb at 58psi. those were had for $150 then cleaned and flow tested at a local speed shop for $20.

Would you happen to have to have the injector data your using for those? Ive been helping someone on here work out their tuning issues and Im not positive that the inj data is correct. hes using the same same injectors as you. I have verified flow rate is correct and would just like a little more confidence about SPA and min pulse width. Since you said you had them flow tested i assume you got data back with them?

[gtstorey]

Would you happen to have to have the injector data your using for those? Ive been helping someone on here work out their tuning issues and Im not positive that the inj data is correct. hes using the same same injectors as you. I have verified flow rate is correct and would just like a little more confidence about SPA and min pulse width. Since you said you had them flow tested i assume you got data back with them?

Any flow test for $20 isn't likely to be anymore than just flowrate@pressure check.

[Alvin]

The knock sensor behavior looks like there is a code at least pending. When it detects a fault with the knock sensors it defaults to the max allowable retard while in PE.

[Pat406ci]

Alvin and 5FDP, you are correct, there were 2 codes: P0103 (Mass or Volume Air Flow A Circuit High), and P0332 (Knock Sensor 2 Circuit Low Bank 2).
I cleared these codes and no more knock. Although they may come back again soon.
BlindSquirrel, thank you for the link for the 51lb L96 Injectors. I ordered them and plan to install in a few days. I am planning on installing a supercharger in the near future, so hopefully these will suffice. Also planning on upgrading the fuel pump. Do you know if I will need adapters with these L96 injectors? My engine is Gen3 LQ4, and these injectors are for the newer Gen. I will send you a PM. Thanks.

[gtstorey]

Ict billet has a chart showing the dimensions of GM injectors and have the adapters if you need them. You may also need different o-rings.

[bradleyhamlin123]

report back with how those injector4s work, im curious if theyll be good for $55 brand new