Howzit,
I was hoping someone with more experience could help me identifying the cause of some knock I've been getting on my 08 TBSS with fairly high mileage 170K. I'm totally a novice with HP tuners, I know how to do the basic functions but have a hard time deciphering my scans what I should be looking at, what's normal, etc. I have a little experience with modern fuel injection but not much, I had 3 87 GN's in my past and those were probably the simplest form of EFI there was, the 06 Chrysler in my sig was the newest car I'd ever owned, electronic throttle was a whole new ball game to me lol... I paid a tuner to do the tuning and later tailored it to my liking after.
The TBSS is pretty much all stock down to the paper filter with the exception of a 160 thermostat and TR6 plugs cause I read that those were supposed to help with KR. I've only owned it for about a year now and driven 10K miles and the PO ghosted after the sale so its pretty much unknown history before that. But I assume this was happening the vehicles whole life. I read 08's in particular are programmed with a lot of knock in them, not too sure what to make of that but just something I read.
So upon logging the stock tune with the scanner out of curiosity I noticed there was some knock occurring at low RPMs, I could never feel it, hear it, and if the scanner wasn't logging I wouldn't know it was happening. The trend I can notice from seat time is it seems to happen at throttle tip in, its not even really tip in I would say, but any non-slow and smooth press of the pedal seems to make it happen. I purposely did some jabs at the throttle in log 11.1 to make it happen. The other logs just show it happening, this is driving to and from work, mostly freeway driving.
Initially I suspected it was burst knock cause it was happening at such low RPM, not much throttle and no engine mods done. It always looks like a mountain peak and decays down like that, I've never seen to sustain/flat line before. So I tried to turn burst knock down but it still seems to happen. I also backed off some timing from my old logs that I took in those areas it was catching it. It still happens even if I keep taking out progressively more and more timing but it makes the truck feel really sluggish so I put some back in tune 11.1. I did also try some Royal purple "octane booster" to see if that would help, it seemed like it might have been less but hard to definitively say cause I know its not really raising the octane much if any and it still was knocking at the same trend so it could have been the placebo effect.
Anyway I was hoping someone more experienced than me could help decipher if this is something tune related or something mechanical that needs to be addressed, or is this normal operation for this year and platform. That's where my inexperience comes in, I don't really know how to analyze what I'm looking at enough to make a confident correction. Nor do I have anything similar to compare to.
I was also trying to log the MAF to possibly adjust the calibration so that's why LTFT's and VE are off. I think the AFR is somewhat close in CL cause in previous logs the fuel trims didn't seem too far off.
Thanks in advance!! Appreciate any insight
Rev 11.1.hpt
rev 11.1.hpl
log 11.1.2.hpl
log 11.1.4.hpl
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Originally Posted by blindsquirrel
