Weird timing issue

LS1, speed density, mild cam, 11:1 compression, truck heads n intake, 36# injectors and shorty headers. Everything else stock. I'm having a weird issue where my timing drops way down in a few spots. It rarely happens. I'm not finding knock retard anywhere on any of my logs. I've had a knock sensor code pop up 2 times in 6 months. Clear the dtc and it doesn't pop back up. My idle timing is also jumping from 12 to 24 suddenly. I had it pretty steady at 18 to 20. Here is my tune and log.

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One note, you can't command a stoich value that doesn't exist for regular pump fuels. They don't sell gasoline that would run 14.9 for a stoich, put it back to 14.68 if running non ethanol fuels.

Remove all that negative timing in the ECT spark correction table too. It's a unrelated thing but you don't need all that.

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Originally Posted by blindsquirrel

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there is no knock retard showing in my scanner at those places. Only those massive dips in a few spots . It doesn't happen all the time and I've been logging every drive. That just seems like alot of timing pulled in random places for no reason. I'm not sure if my scanner isn't set right or I am overlooking something. Could a bad knock sensor be causing it?

Thank you both

The screen shot dip he posted was on the shift, it's pretty normal to drop timing on the shift. Removing power helps the transmission a lot.

Quote:

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Originally Posted by 5FDP

One note, you can't command a stoich value that doesn't exist for regular pump fuels. They don't sell gasoline that would run 14.9 for a stoich, put it back to 14.68 if running non ethanol fuels.

Remove all that negative timing in the ECT spark correction table too. It's a unrelated thing but you don't need all that.

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I set stoich back. Where are you saying to pull the neg timing from?

I guess you mean here in the picture

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I see what your saying on it pulling timing in shift points, just haven't seen it logged in my scanner like that before.

Thanks again for your help.

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If you log the things used in those tables, like trans current gear and delivered torque, it will make a lot more sense.

That appears to be a normal timing pull on what looks like the 1 to 2 shift judging by mph

You really do not want to have big jumps from one column to the next in either of these tables like this.

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Usually any difference less than 5* is ok depending on the setup. Less is better tho.