Knock retard issue LQ9.

Hey guys, just recently bought an 04 Silverado rcsb with an lq9, 224 230 cam, P&P 317's, built trans, 3600 converter, 4.11 gears, eaton limited slip, polished throttle body and an under drive pulley. I am having a knock retard issue with it that I can't seem to figure out. The truck was dyno tuned at Futral a few years ago where they are extremely familiar with the truck and to make it short, their customer service and staff is awesome. They bent over backwards answering all my questions and even gave me some pointers as to what to try next. They said it has made 35 pulls on their dyno, so I feel like the tune should be ok. I first pulled the tune and sent it to Allan to see if it was the same tune, which it was. After hearing back from them I checked my exhaust to make sure it wasn't hitting anything, I changed my knock sensors and harness and also cleaned my MAF sensor. When I finished with all of that, I logged the truck and the knock retard is still there. I then pulled some timing in the areas where it is KRing and I still have knock retard. I have tried instead of 91 octane fuel, 93e10 (I have read in some instances the ethanol actually helps KR) and the KR is still there. My valve train doesn't seem to be any noisier than any other LS motor with a cam. I'm completely stumped and have no idea what to try next..

Here is the tune file for the truck and my very first log.

Here is a log after an octane booster.

Here is a log after a SMALL timing reduction.

Here is the log after I changed the knock sensors, harness, cleaned MAF and added 17 gallons of 93e10 fuel. There is a pattern as to where the truck is KRing. It is always bad between 1400 and 3600 RPM's. The WOT knock retard I think is false or there is very little of it. The reason I say it is false is because the roads in Louisiana are terrible and on the logs where I am getting the KR at WOT is from me either losing traction or from hitting bumps in the road. There is one log file that I have, I don't know if I posted it, that has 0 KR at WOT and that was on a smooth road with no wheel spin.


Thanks in advance for the help,

Erik

Oh and I don't think I have any exhaust leaks. I'm not hearing any audible knock, but I don't have a trained ear for KR. Every time I have heard it in the past, it sounds to me like an old Ford 7.3 powerstroke. I know everyone says it sounds like ball bearings in a tin can, but every time I try to understand what it sounds like I ask the person trying to explain it to me if they have ever heard a powerstroke and they usually say that's a great example of what it sounds like.

geeze, that's a lot of KR. Mostly all at light throttle.
I wish some f the sharper tuners would comment.

The stock decay rate is really conservative. You can see that clearly on some of the single knock events.
Some of your other events it looks like it sees a number of events in a row.

You might try reducing the decay.

But really need to figure out what the cause is.
The tuning school suggests reducing timing in the area before where the KR occurs. Knock it down 5 degrees or more.
When trying new fuel, try 100 octane race gas.
I just have the books, I didn't take the class. :-)

I guess I'll ask. How long since new plugs? Same kind as when it was dyno tuned?

Since I don't see any KR when on the throttle, they may never have seen that when doing pulls.

Ron

Quote:

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Originally Posted by RonSSnova

geeze, that's a lot of KR. Mostly all at light throttle.
I wish some f the sharper tuners would comment.

The stock decay rate is really conservative. You can see that clearly on some of the single knock events.
Some of your other events it looks like it sees a number of events in a row.

You might try reducing the decay.

But really need to figure out what the cause is.
The tuning school suggests reducing timing in the area before where the KR occurs. Knock it down 5 degrees or more.
When trying new fuel, try 100 octane race gas.
I just have the books, I didn't take the class. :-)

I guess I'll ask. How long since new plugs? Same kind as when it was dyno tuned?

Since I don't see any KR when on the throttle, they may never have seen that when doing pulls.

Ron

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I'm sure the plugs are probably the same. They are either the NGK tr5 or tr55, I can't remember. I considered changing them next. I pulled one from each side when I first discovered the KR and they looked flawless. I'm going to pull a total of 5 degrees across the whole board today and see what happens. I'll report back with the results.

Thanks,

Erik

Quote:

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Originally Posted by RonSSnova

geeze, that's a lot of KR. Mostly all at light throttle.
I wish some f the sharper tuners would comment.

The stock decay rate is really conservative. You can see that clearly on some of the single knock events.
Some of your other events it looks like it sees a number of events in a row.

You might try reducing the decay.

But really need to figure out what the cause is.
The tuning school suggests reducing timing in the area before where the KR occurs. Knock it down 5 degrees or more.
When trying new fuel, try 100 octane race gas.
I just have the books, I didn't take the class. :-)

I guess I'll ask. How long since new plugs? Same kind as when it was dyno tuned?

Since I don't see any KR when on the throttle, they may never have seen that when doing pulls.

Ron

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Hey man, sorry it took so long for the next log. Here is a log with 6* of timing pulled across both the low and high octane tables. The truck ran kind of funny and made a couple of strange sounds. Maybe sounded like it was backfiring through the TB? Idk.. I put the original tune back in it today and the strange sounds went away.

Here is just a quick log from today after I put the original tune back in it. Could a bad MAF sensor cause false KR?

Quote:

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Originally Posted by OlympicWhite 5.3

Here is just a quick log from today after I put the original tune back in it. Could a bad MAF sensor cause false KR?

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Bump. Come on guys I need a hand with this. I'm stumped. Any input would be great.

Set all your knock sensor tables the same as this stock 2004 Silverado SS. As some of your 5.3 knock sensor tables are more sensitive.

Russ Kemp