LT Knock and ST Knock Issues at Cruising Speeds

[Peter_beresky]

I was experiencing light knk with 91 tune also around 1600-1900 rpm with light throttle before the update. It was about 1-2 higher with the 93 tune on avg.

[RT23]

Ok, sounds like the 91 tune is the way to go for now. I appriciate the info. I will try the 91 tune and adjust.

Updated: Installed the 91 tune. Fuel Retard and ST Retard reached 4 at around 4k rpm. Upped fuel % across the RPM ranges twice, reaching a max of +7.5% fuel. I did see ST Retard and Knk Fuel Retard at a 6 max at 3488 RPM at 86 mph after getting out of residential areas, to an area where I could push the car harder and go WOT. This high number was after increasing fuel up to 5% across RPM range. I also had two misfires. The car had been sitting for a while, had a chance to cool.
After this I restored backup, making no changes. Fuel Retard and ST were seen at 2 at 3808 RPM and up to 4 at 2872 RPM. No misfires. This seems to be the case each time I see misfires, the engine is cold. I realize that putting an engine, gasoline anyway, under load at low rpm, easily done with standard trans, can cause one of the forms of "knock", just don't know where the acceptable threshold is. That is where I am seeing some knock, at highway speed, allowing speed and RPM to drop, then apply throttle. I didn't think that the RPMs were dropping too low, judging by engine sound. But then again, I've never seen a knock sensor readout either. When I see the knock sensors spike high, I let off throttle, that is why RPM is not any higher with knock. I did reach higher RPM. Two examples are just over 4300 (was peak and I didn't get exact from data viewer), with Fuel Retard and ST at 5.5. Another was in the 4700 RPM range with Fuel Retard and ST at 3. Both sets of knocks were picked up on the downside of RPM, during a gear shift or clutch depress. This car is new, just over 6k miles, so I don't want to push it too hard.

I don't know if this will help anyone, or the Diablosport programmers, but there it is.... again.

[txsport]

Mikel,

Any update as to what we should do?

Change any parameters? Not worry about it? Return to stock?

Thanks

Trent

[stroudtom]

I had LT/St knock anytime the ECO ON was light, especially at low speeds, 1500-1200 rpm. Stock tune had the least but still there. Turned the ECO off with manual shift mode and almost no knock. I'm going to city drive with it off with the "mileage booster" tune and see if I can equal my average city MPG of 16. Nice how much quieter the ride is without all the harmonics going on.

[txsport]

I ended up paying for a cmr tuner to make adjustment. His comment was that there was unnessesary spark advance. I got his file and now i have no LT or ST kr at cruise and only a blip of ST kr which is how it should be.
I didnt lose any performance at all, in fact, i gained a little.

[joemosfet]

I ended up paying for a cmr tuner to make adjustment. His comment was that there was unnessesary spark advance. I got his file and now i have no LT or ST kr at cruise and only a blip of ST kr which is how it should be.
I didnt lose any performance at all, in fact, i gained a little.

Was it a true custom CMR tune or did he just mess with the modify parameters? Do you have a 2011+ vehicle?

[txsport]

He can change more parameters than we can with our trinity so I would say yes, a custom tune not just a altered canned tune that i could have done myself.
He firmed up the shift and change the shift RPM. He also pulled the unnecessary advance(we could do some with trinity ourselves mainly WOT not partial).

So it was a true custom tune but based on the DS tunes. While mine personally is not dyno proven, his methods are. There are others on other forums for rams that have dyno'd his tunes and made some impressive gains vs the canned DS tunes.

[stroudtom]

Are you driving with MDS on or off?

[txsport]

It didn't matter if the mds was on or off. I had the same issue either way. I even tried to correlate it into whether or not it was going into and out of MDS mode maybe providing a false KR issue. One thing is that with the windows down you could here it pinging.

Now with the new tune(MDS enabled) I only get a small ST KR at wot and absolutely NO KR at all while cruising or any lower RPM.

I could even just turn a corner and give it a little gas to get going without having it downshift and it would give me both ST and LT KR. Definitely an issue in my book.

[RT23]

No expert by any means (in fact you could say I have a partial thimble of knowledge out of a 55 galon drum), but it sounds like it may have been "lugging" your engine down due to a lack of downshift and dropping RPMs, then putting the engine under load, with one of the knocks you were describing, obviously not the WOT knock. Hopefully, in the near future, we will have more options to tune with. Thing is, you said you had knock with stock tune, so that sounds like it was possibly/probably there before any changes were made. May be a good thing it was caught with the Trinity before any damage could have been done. Glad you got it taken care of!

As far as MDS, I have an M6, so no MDS but still have knock. Not saying that it isn't an issue, just throwing it out there.

[txsport]

Oh if I said I had it on stock then I mis-spoke. I have ZERO KR with the truck as it was from the factory. The most I have seen is like .5 ST and that was ONLY under WOT. I have not made any modifications to the truck not even intake.
If I load the DS tune, the Stock with modifications(DS canned tune) and don't make any changes I get KR both LT and ST. That right there shows me its the DS canned tunes.

I would agree with the lugging if it were not an automatic and the fact its not lugging for sure. The motor should not lug going down the freeway doing 70 and even going over an over pass. I live in TX so there are no mountains just small hills. One other thing I noticed is that I don't get KR until the motor temp gets above 160. Not sure if that has to do with the fueling tables and open loop vs closed loop.

I have built and tuned lots of turbo cars and know a thing or two about KR. I am no expert at all but I do know that the motor should not be seeing KR of any kind just traveling down the road with out some expected huge motor load before the tranny has a chance to shift down which is not my case.

[stroudtom]

I never checked the stock tune with Trinity monitoring for KR, odd the "stock modified" would be corrupt.

Did you get a e-mail tune for this?

[txsport]

The stock tune that you can modify was one of the canned tunes from DS

[sharkcohen]

I'm seeing this issue as well on my 2012 Challenger SRT8. I captured these logs while running the stock modifiable tune, unmodified. Just cruising down the road.

I have returned the backed up factory tune back to my car, and I have done some datalogging and I have not seen this KR activity while cruising. In my opinion, something seems to be wrong with the canned tunes if even the stock modifiable tune is showing this KR while cruising.

[mikel]

anyone that is seeing an issue and can post up their last tune written, please do so...