Why so much KR ?, 2013 Jeep Wrangler

[bluegoat06]

It's driving me crazy, a little bit of details, Vehicle is a 2013 Jeep Wrangler Unlimited, Auto, 4.56's, 35" tires, no modifications to the engine, no supercharger or anything, 91 octane since day one despite what the damn manual says , it's a got a much of extra weight courtesy of steel skids, bumpers etc, about 400lbs more than stock, but the gears get the job done without issues.

KR only seems to manifest itself when the outside temps are hot, 6-8* KR according to the PID, nothing on the WOT side, only during part throttle, between 0.52 and 0.60g aircharge, and 1700-3100 rpm.

Initially i thought it was just as simple as removing 2* from the part throttle timing table, from there i did remove up to 3* from the table, only to see the same amount of KR.

Then i thought maybe the KR was related to high IAT's, so i started playing with the IAT table, same results, tried removing as much as 8* from that table, only to see the same amount of KR in the logs.

So as a test, i loaded the factory timing, and pumped 5 gallons of 100 octane with 9 gallons of 91, so the cocktail was around 94 octane, freaking KR was still there more or less in the same areas.

I did modify the KS sensitivity after that test, increasing the knock sensors threshold volts by about 15%, to my surprise, KR is till there, better, but still there, and i don't think i want to continue numbing them down, i thought i'll halve the long term KR table as a way to desensitize the KS logic a little further, but i wanted to ask for more opinions.

Looking at some other KR PID's 3 days ago, i noticed we have a short term KR, and long term KR pid, and i started observing this values, most of my KR seems to come from the long term KR pid, while some sporadic one is short term, so it makes me wonder about this specific PID ?
Is this long term KR a combination of other knock retard adders like IAT or ECT adders?, and i'm just chasing my tail for nothing ?

I'm attaching mt factory and modify tune, as well as my last log form today with my modify tune, hoping somebody can give me some more pointers on how to address the issue, perhaps something i'm not seeing in my tune.
There are 2 logs, both were taken with the same tune, the only difference was 94octane in the tank, vs 91 octane for the other.



Thanks a lot

[bluegoat06]

Anybody ?
Would be safer if i return the knock sensor levels to factory, and diminish the long term KR values instead ?
Does long term KR adders included IAT correction ? Burst knock correction etc ?

[bluegoat06]

Im i logging the correct knock retard PID ?
I'm looking at my Histogram and charts, and the scanner is using a Spark Retard (sensor) to show KR.
but looking at my logs, i discovered a discrepancy in what the damn sensor is displaying vs the PID's i'm data logging.
For instance, in this particualr frame, KR shows 4.7* in the chart and histo, but the short term KR, long term KR and total knock doesn't show that ???
Or is just a delay in the way the data is being display ?

Please help, what should be the absolute official knock reatrd PID for the Dodge or Jeep Platform ?
And what is this "Spark Retard(sensor)" value, as far as i know, it does't even look like it's on my PID list, or at least i'm not seeing it, yet, it's what the scanner is looking at in chart and histo....

KR1 by Wrangler RSM, on Flickr

[06300CSRT8]

The graphs will be an average of the entire log (open you have selected) or an average of the view in the charts. The Charts will be that point in time.

Can you post up your log? The charts and actual PIDs will differ due to interpolation between the points. The charts will allow you click at almost infinite points to see values, but you didn't necessarily record anything that that very split second, and so are actually being shown a line that connects from the previous actual recorded spot (0* based on your PID) and then next recorded spot (-5* it looks like). Your PCM commands knock in 0.5* increments, when you see anything else in the charts, its usually the interpolated value.

[bluegoat06]

Here it is referenced in the print screen.
Since then, i've tried a different approach, putting the KS values back to stock and modifying the LT knock, nothing changed, then that + the KS modded values i have, nothing changed.

Today i was trying to simply reduce timing using ECT and IAT,tables, as the Jeep engineers thought not reducing timing in the 2200rpm- 2600rpm for the ECT and 3100rpm for the IAT, at least at the same rate they do for the other cells around it, quiet frankly, i never seeing something like that before, plus the damn tables are not referenced by aircharge cells specific, but a global table that i guess is referenced by % of temp instead, my KR seems to be concentrated in the 0.52-0.60 g area, makes me wonder if i just need to enable WOT a lot earlier lol, in any case, nothing changed.

Could be oil blowby, i don't have an oil catch can hooked up in there, cause i didn't think i needed one, and i haven't seeing any other logs from an application with the Pentastar motor to know weather the KR is normal, like i think it happens in the 6.4L and 5.7L motor, or not.

What's weird is that it doesn't matter what i do to kill that KR, it comes back with force in the same areas, i don't hear the motor knocking at all, and it does seem to happen more often once the motor has been heatsoaked.

[bluegoat06]

What's the relation between ST knock and LT knock with spark retard ? i've tried to find more about this in this section, but i don't see a lot of references to something in concrete, other than some people saying desensitize the sensors or add more fuel. i'm looking to understand the fundamentals in the Dodge application when it comes to knock

[bluegoat06]

Going back to the basics, i did remove about 5-6* as a test from the PT timing table in the areas where i see the most aggressive KR when things get heated.
I'll do another log today to see if something changes.
Tune with the new timing hand smoothed in the PT timing table.

[bluegoat06]

New timing worked, 5-6* less than factory in the load/low rpm areas. why would Jeep print in the manual using anything higher than 87 octane can be counter productive is beyond me, i can't believe even 94 octane will produce KR at that load ???

This was the only KR event, 5.5* but it seems to be some sort of fluke, timing is clear from the big KR events from yesterday.
This is the same road i take every day, with some long hills, log attached.
kr2_newtiming by Wrangler RSM, on Flickr

I can't also believe nobody has chimed in with a simple explain for the KR PID's ?? have HPT support posted about it ? i've looked but nothing comes on in searches, so if this was something that has been beaten to death i could understand some people thinking i'm too lazy too search , so i have to ask one more time, what's the relation between ST knock, LT knock and spark retard ?

Anybody from HPT support care to give the little details ?
Thanks a lot.

[5FDP]

Most car makers run vehicles with knock from the factory, it's not hurting anything at low load and low rpm.

GM puts predicted knock into almost all the GEN 4 and GEN 5 computers/calibrations, doesn't surprise me that Ford and Dodge do the same exact thing.

[The Speed FoX]

well, I have had a similar problem on my 2013 charger 3.6L, i switched to 91oct and the car is recording about 6 degrees of knock on stock tune partial throttle spark table, but when i go full throttle it goes smooth with no problems, i even added 4 degrees of timing in WOT spark table, my charger is not stock, it has an intake, throttle spacer, ported intake manifold, exhaust system and deleted cats!

and my guess is its normal for it to record some knock on a low load, but I switched back to a higher octane gas.

[bluegoat06]

Is 0.48-0.60g aircharge considered low load ? if you look in my logs, the regions of the timing where it knocks is typically 96-98 KPA MAP, sure at low rpm, but I think that's a lot more than low load no ?
In any case, it seems peculiar that most of this KR was registering in there when they day was hot, and in 100F+, there was KR all over the place, mostly induced in those high load/low rpm areas. I've never ran 87 octane to see how that KR looked like before.

[SultanHassanMasTuning]

did you change or zero out the short/lng term under ignition map, which is used for tip in situations?

[bluegoat06]

. wrong thread