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help me find my knock issue

Old Oct 11, 2016 | 06:51 PM
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Ok guys I'm looking for a little guidance. I have been tuning on the truck and feel that my VE is pretty good(I will work it a little more here and there). I am getting a knock when I roll into the throttle and its sucking all the timing out of the truck. If I go WOT I'm not getting this knock. I have replaced the rear knock sensor it was throwing a code and replaced the harness also. I am commanding 11.2:1 on both the PE and BE. I have my PE set to come in at 85KPA and 25% throttle. I will attach the tune and a log so you can see what I'm referring to as my issue. also for some reason prior to PE coming in, I'm getting a commanded 12.05:1 AFR that I cannot seem to find in my tune. any advice is greatly appreciated. at 09:44 you can see a good example of the problem I am dealing with.
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Old Oct 11, 2016 | 06:54 PM
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I guess a mod list would be kind of important also lol

2003 5.3 3Bar HP tuners SD tune
S475
holley hi ram
ID1000
walbro 450
4l80E/AWD(149)
3600 FTI converter
stock cam/internals
6PSI
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Old Oct 11, 2016 | 06:58 PM
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I have tuned the VE up to 80kpa I don't think there's any reason to go higher is there? I would want it richer prior to boost correct? So up to 80kpa is 14.68
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Old Oct 11, 2016 | 07:34 PM
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I noticed your commanding 14.68 are you running strait gas? I had random knock until I changed my commanded afr to 14.13 which is stoich for e10.
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Old Oct 11, 2016 | 07:36 PM
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Why was timing so low before it even picked up knock? Sometimes that will throw it off too.

Also you need to make it decay faster. Such a slow decay makes it hard to tell what areas need cleaning up.
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Old Oct 11, 2016 | 07:46 PM
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Originally Posted by JHForman
I guess a mod list would be kind of important also lol

2003 5.3 3Bar HP tuners SD tune
S475
holley hi ram
ID1000
walbro 450
4l80E/AWD(149)
3600 FTI converter
stock cam/internals
6PSI
Originally Posted by xr650jkallen
I noticed your commanding 14.68 are you running strait gas? I had random knock until I changed my commanded afr to 14.13 which is stoich for e10.

I was just contemplating changing the stoich value for the e10 actually but I've done a ton of reading that says it's not enough to really matter. Plus every pump here says UP TO 10%, without actually measuring each and every fill up it's hard to say if it's really e10 or not?
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Old Oct 11, 2016 | 07:50 PM
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Originally Posted by JHForman
I guess a mod list would be kind of important also lol

2003 5.3 3Bar HP tuners SD tune
S475
holley hi ram
ID1000
walbro 450
4l80E/AWD(149)
3600 FTI converter
stock cam/internals
6PSI
Originally Posted by Vortec350ss
Why was timing so low before it even picked up knock? Sometimes that will throw it off too.

Also you need to make it decay faster. Such a slow decay makes it hard to tell what areas need cleaning up.

That's what I'm trying to figure out, I'm not sure why if sucks all the timing out of it. I thought it was burst knock at first but I got rid of that. What should I change the decay to? My high octane table is commanding 6 degrees in that area I believe ? But once it knocks it should switch to low octane table and I've already pulled timing from it trying to fix the issue. I would have to look at the tune but I believe it's commanding 3 or 4 on the low octane table. After reading last night on HP forum the custom os runs on the high octane table in SD mode and switches when knock is detected
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Old Oct 11, 2016 | 11:56 PM
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Originally Posted by JHForman
I guess a mod list would be kind of important also lol

2003 5.3 3Bar HP tuners SD tune
S475
holley hi ram
ID1000
walbro 450
4l80E/AWD(149)
3600 FTI converter
stock cam/internals
6PSI
Do you have an aftermarket IAT sensor? Looks like your calibration is off from a stock 2003 file I found in the registry and my 2002 pcm. It's not much but just curious as to where your values came from.

Also - it looks like the timing is being pulled right before a downshift or something

- check the "Traction Control Spark Retard vs RPM" table. Mine is zero'd out and yours looks like it's pulling a ton of timing out based on that table. it's under torque management/general/TCS method/Retard vs RPM button.

Also - I have both the prevent downshift and hold gear disabled...not sure if that matters for your issue.
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Old Oct 12, 2016 | 01:32 AM
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Originally Posted by Ken in AZ
Do you have an aftermarket IAT sensor? Looks like your calibration is off from a stock 2003 file I found in the registry and my 2002 pcm. It's not much but just curious as to where your values came from.

Also - it looks like the timing is being pulled right before a downshift or something

- check the "Traction Control Spark Retard vs RPM" table. Mine is zero'd out and yours looks like it's pulling a ton of timing out based on that table. it's under torque management/general/TCS method/Retard vs RPM button.

Also - I have both the prevent downshift and hold gear disabled...not sure if that matters for your issue.
It's a GM style IAT sensor, I calibrated it free air it was reading about 10 degrees high all the time so that's why the values were changed, should I put them back?

All that retard that is at 09:44 is done in 3rd gear. No down shifts this is just rolling on the throttle. I wondered about that traction control part I'll 0 it out.

Is this knock that is showing up or just retard that could be coming from somewhere else ? Unfortunately there's not a way that I can find to actually see the voltage being reported by the knock sensors? I looked all through my PiD list and couldn't find them am I missing something ?
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Old Oct 12, 2016 | 01:45 AM
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Right at 16:18 I saw that rpm bump but now it looks like the converter unlocking?

Zero that table out and see what happens. Be careful obviously

I'm not sure about the IAT sensor calibration, I would put them back if it were me, but thats up to you. Seems like a variable that doesnt need to be messed with, but that may mess with your VE a bit too if you change it back.
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