2015 tahoe cruising knock retard

[Knockretard]

i have been chasing my tail with my daily driver
its a bone stock 2015 tahoe with only cai using 87 oct
i get crazy amounts of knock while cruising i tried dropping timing down it wont go away
it happens around 20% + throttle when i blip the throttle.
i have read about burst knock but idk exactly what's causing it !

attached tune file and log

[Alvin]

That's pretty normal with what I see around here. They really do better on 93 or E85.

You can pull timing from the effected areas or you can try better gas.

[Minter348Racing]

doing this myself. I'm on a super aggressive mud tire. its a 37/13.50/22 Yokohama MT2 and they don't make lots of road noise but they're knobby.
I've raised the knock sensor sensitivity quite a bit. 93 for me hasn't changed anything.
I'm lucky to hold 16* of timing cruising. Sometimes it'll be pulling 6-10 degrees out. Put in Solid motor mounts. nothing different. Changed knock sensors, made sure to torque to 18 ft lb. nothing.
Truck is a FBO l83 with literally everything you could do to it. Slowly learning but I cant figure it out either myself.

[TriPinTaZ]

Normal on 87 octane. You don't need to reduce the timing, the ECU logic will automatically back it down over time(assuming you didn't alter the knock retard logic) Aftermarket intakes will typically exacerbate the KR for varying reasons.

Additionally, some OEM tunes have static knock tuned in and it will ALWAYS show knock retard(even if its not real) because the static knock table is populated.

[Knockretard]

so should i put back stock spark table?
should i be using 91 instead ?

[pronstar]

My 2015 did this for the first couple years I owned it?then it just stopped and to this day runs fine on 87.

I never touched the tune. All I can think of is maybe the dealer did a reflash at some point?

My 2018 has run great on 87 the whole time I?ve owned it.

[TriPinTaZ]

so should i put back stock spark table?
should i be using 91 instead ?

yes put it back to stock. Look at the static knock table, its possibly populated. This will show as knock in the scanner.

91 will have better performance. 87 will cause the ECU to learn to pull timing out and it will continue to keep it pulled out. It's a built in logic in the ECU.

My 2015 did this for the first couple years I owned it?then it just stopped and to this day runs fine on 87.

I never touched the tune. All I can think of is maybe the dealer did a reflash at some point?

My 2018 has run great on 87 the whole time I?ve owned it.

Likely because of the ECU's logic of "Knock Learn". The ECU will learn knock, and automatically start moving timing towards the low octane table and keep it there until the fuel gets better or it sees that it can add timing back without knock.

[[email protected]]

so should i put back stock spark table?
should i be using 91 instead ?

No pro here so there's that, but at 11:39.296 your showing 9.1* KR @ 99.6% engine load @ about 1300 RPM. You're not logging enough channels to see if it's a torque management issue. But your low octane table is commanding 14.75*ish timing, and doing the reverse math 14.75-9.1=5.65*. I added 5* to mine, and I still get a little KR but not nearly as much as yours. I would also recommend changing your driver demand back to stock or closer to it, and using the driver demand editor that CYN_CRVR created found here; https://forum.hptuners.com/showthrea...rottle-mapping Again I'm no pro but I don't think a CAI warrants all of the AFR and airflow changes.

[Knockretard]

yes put it back to stock. Look at the static knock table, its possibly populated. This will show as knock in the scanner.

91 will have better performance. 87 will cause the ECU to learn to pull timing out and it will continue to keep it pulled out. It's a built in logic in the ECU.








Likely because of the ECU's logic of "Knock Learn". The ECU will learn knock, and automatically start moving timing towards the low octane table and keep it there until the fuel gets better or it sees that it can add timing back without knock.

which one is the static knock table?

[Knockretard]

which channels should i add and keep an eye on?

[[email protected]]

which channels should i add and keep an eye on?

I use these.Gen5 AEM Channels.xml

[Alvin]

If you think that you truck just stopped knocking all of a sudden watch "Knock Learn Factor" You are likely going to be in low octane mode.

The cost between premium and 87 isn't that much. These are fairly high compression motors. Mileage is usually better when the truck isn't knocking. It just makes sense to run 93.

[Knockretard]

yes you are right i will give that a shot and log again, thanks !

[Knockretard]

thanks man!!

[Knockretard]

i have been trying to setup the scanner like he did in the video ( graph layout info) have you done that?