knock at zero degrees advance

[fastNYsix]

Has anyone seen KR at zero degrees of advance? Not sure how this is even possible. I swapped out the LC9 for an L96, everything is stock. I've spent over a year on this thing and can't rid of the knock. I've tried new plugs, swapped coils, wires, premium fuel. There doesn't appear to be a shift or converter locking. it happens around 20:28 on log. Any information is appreciated, thanks
garbage3.hpl2011silverado smoothed after trans reset.hpt

[blindsquirrel]

That's some kind of clanky mechanical noise the sensors are picking up, not something happening inside the cylinder.

[Alvin]

Knock sensors usually get super sensitive or super dull when they go bad. This could maybe just need a new set of sensors torqued properly.

[fastNYsix]

thanks, I'll replace them. DO you have a log of what a typical gen4 should look like?

[fastNYsix]

Ok thanks, So I am correct in assuming that real knock is not possible at zero advance on a stock setup?

[Alvin]

Usually a situation like this is going to be a bad sensor, banging exhaust, sensor loose or too tight.

Very rarely will it be something else like injectors

[JayRolla]

Thats what they call false or phantom knock like everyone is saying. Do you get knock at WOT? Make sure the exhaust is not hitting anything like frame rails, should be completely suspended by the rubber hangers. Also make sure the knock sensor is torqued correctly, I had a motor do this when the sensors were over tightened.

[blindsquirrel]

Get a 1lb rubber mallet, go over ev-ry-thing under the vehicle. tap tap tap Tap Tap Tap TAP TAP... stuff will resonate, some things will resonate up to a certain point then a tinkly rattle or buzz will come in. Hard to explain. Use the corner of the face of the mallet, so the whole face isn't slapping against the part. You want to make the things vibrate, not whack them around.

[fastNYsix]

Ok thanks, Yes I'm getting knock at wot also.

[blindsquirrel]

screenshot.18-04-2024 17.35.11.png

^^^ That right there? That's a rattle, not knock. Nothing changed in any of the data that would make it knock. Nothing.

You don't have knock at WOT also, you have a rattle that triggers the sensors at random times and some of those random times also happen when WOT.

[fastNYsix]

Ok thanks, I ordered knock sensors. I've noticed there's a misfire that sometimes coincides with knock event. I banged around on stuff but didn't notice anything unusual. Oddly, 93 octane seems to improve the situation.

[JayRolla]

Ok thanks, I ordered knock sensors. I've noticed there's a misfire that sometimes coincides with knock event. I banged around on stuff but didn't notice anything unusual. Oddly, 93 octane seems to improve the situation.

Make sure you install GM original sensors. Not aftermarket.

[fastNYsix]

ok thanks, will do. I did some wot blasts tonight and definitely heard pinging.junk2.hpl

[edcmat-l1]

Looks like you have at least 1 problem cylinder on bank 1. And if you hear pinging, that's not good.

[Alvin]

ok thanks, will do. I did some wot blasts tonight and definitely heard pinging.junk2.hpl

This could be injectors.

I had a car earlier this year that audibily knocked HARD with very little timing in it. I tried all sorts of things. Finally came to the conclusion the crate engine the guy brought us must be 13:1 or something and E85 was going to be the only way forward. Well we pulled stock LS3 injectors out for 850's and the problem completely went away. Fueling didn't change before or after.. drop in injector data and go. No misses, nothing else odd other than TONS of HARD knock. If someone told me that i would think they were crazy. But it happened to me.

[JayRolla]

ok thanks, will do. I did some wot blasts tonight and definitely heard pinging.junk2.hpl

Oh, that's not good. Didn't know you could hear the ping. Definingly need to look into fuel delivery. If pump, fuel pressure is good I would think about trying to swap some other injectors over like Alvin said. Either some other OEM or quality injectors with good data like injector dynamics.

[fastNYsix]

Ok, I was thinking injectors also, so I installed 8 new gm injectors for 5.3 truck engine #12613411. No change. Would fuel delivery issue show up on the o2 reading? I'm going to try new plugs. check engine light for bank 2 long term fuel trim back on.

I'm currently running stock 5.3 pcm, vve and maf table with this 6.0. I tried disabling the maf to get vve table better but caused massive problems, extreme timing events that hp tuners couldn't explain, and maf map correlation codes, limp mode. Alvin commented on this problem I had 2 years ago. I tried increasing vve table and maf table but still had the knock. So I am back to almost 100 percent stock tune except for I pulled some timing from high timing table. I've tuned gen3 and v6 turbo and supercharged cars, never seen or heard knock like this.

[fastNYsix]

Looks like you have at least 1 problem cylinder on bank 1. And if you hear pinging, that's not good.

How can you tell its bank 1?

[Alvin]

I agree.. Something is going on with bank one

[edcmat-l1]

How can you tell its bank 1?

By reading the squiggly lines.