Still Knockin'

[Aloicious]

Hey,

Well, I loaded up the tune that Aloicious put together for me and the car ran very well on it. The main purpose of the tune was to help me find the cause of my KR. I would seldom get KR when going WOT off the line or standing on it. Normally, I get it when rolling on the throttle and causing a downshift, but not at WOT. Before this tune I could never get rid of it, regardless of how much I dropped the timing in the problem area.

So, out of the kindness of his heart, Aloicious put a tune together to help me out. The tune ran very well but the KR still happens in the same areas. More and more, I am thinking that it is a false knock. It always occurs at the 3>2 shift. I know my relocated torque arm slaps hard going into a load.

I attached some images of KR, the first log of the tune and the tune itself.

Comments welcome.

Thanks

you can also see that since I raised the KR limit from 4* to 15*, there are times you're getting WAY more knock than the 4* you were getting earlier. so now, what I would do, is go extreme on it, take those areas that you're getting the knock (looks like up to 11ish* in some places) and lower the spark map 11*+ and do some more logs, also try making the mixture richer too. if you lower them THAT much AND increase fuel, and if you're still getting the same amount of KR, I'd say its probably not spark/fuel related, and false knock or a bad sensor may be the culprit. but you really want to rule out spark or AFR as the cause first. make absolutely sure it is not a dangerous or problematic condition first before jumping to false knock. but if you lower the timing and richen up the mixture and it DOES dramatically reduces the KR, or eliminates it, then you can rule out false knock.

also something I noticed is your knock sensitivity settings are quite a bit different than the 2002 OS, I'm guessing it is from your PCM swap and the table migration but in looking at the 98-99 knock tables, they're quite a bit different, even the tables that are offered are different. I wonder if you should transfer the knock sensitivity tables to what the 2002 OS has and if that would make a difference. hopefully someone with more experience with setups simmilar to yours will chime in.

[Aloicious]

What was the change in the tune...?

I lowered the spark maps in the troubled areas, increased the KR limit, thats basically it. you can see the difference in KR from the raised limit alone. he had it at 4* max, i set it at 15* so we could see what the PCM was trying to pull since he was maxing out on the 4*.

edit- I also increased the KR recovery rate

[tatasta]

Here's the new tune that I intend to run. The spark has been edited based on the KR map and AFR is dropped to 12.2:1.

We'll see how it works. The worst area that KR was happening is lower by a total of 18 or so degrees from my original tune (before Aloicious worked it over the first time).

I will post up some logs soon.

Thanks

[Aloicious]

Here's the new tune that I intend to run. The spark has been edited based on the KR map and AFR is dropped to 12.2:1.

We'll see how it works. The worst area that KR was happening is lower by a total of 18 or so degrees from my original tune (before Aloicious worked it over the first time).

I will post up some logs soon.

Thanks

I can't look at the tune, I'm at work, but if its 18* less than what I saw, and you STILL get the same knock, then I'd say you could likely rule out actual spark related knock and look into stuff like false knock. I'm also curious about the knock sensitivity tables too. but we can look at that after you try this new tune.

[tatasta]

Here are some items from the last run. More spark pulled from Aloicious' initial tune. Same results. Up to 6+ degrees of retard mainly across the 4800 rpm row. The only real change I have seen is a 0.7 second slower 0-60 time.

On a good note, I do have my actual AFR matching commanded pretty well. Still a bit of tweaking to do in the cruise/idle areas. The cars starts easier, runs smoother for the most part and seems to have a bit better overall drivability. Thanks to all of you for all of that.

Bob

[Aloicious]

Here are some items from the last run. More spark pulled from Aloicious' initial tune. Same results. Up to 6+ degrees of retard mainly across the 4800 rpm row. The only real change I have seen is a 0.7 second slower 0-60 time.

On a good note, I do have my actual AFR matching commanded pretty well. Still a bit of tweaking to do in the cruise/idle areas. The cars starts easier, runs smoother for the most part and seems to have a bit better overall drivability. Thanks to all of you for all of that.

Bob

I'll have to get my laptop and check out your log and tune, but I agree, if you were getting 6ish KR with my tune, then that spark map you posted is at least 8* lower than my version, and you're still getting 6ish degrees of KR, somethings up thats not spark related. I'll take a look tonight and see whats going on.

[joecar]

If you get knock sufficiently "large/intense" to cause that much KR I would imagine it would be clearly audible... can you actually hear it...?

[Aloicious]

If you get knock sufficiently "large/intense" to cause that much KR I would imagine it would be clearly audible... can you actually hear it...?

I agree.

[tatasta]

If you get knock sufficiently "large/intense" to cause that much KR I would imagine it would be clearly audible... can you actually hear it...?

I agree.

No, I have never heard my car knock. I know what it sounds like and am confident it is not happening.

Since it shows up mainly at one rpm range (~4800 rpm), would resonace make sense or would it be more likely that a part is failing?

Thanks

[joecar]

Resonance from valvetrain noise, piston slap, headers banging frame, loose bolts on accessories or motor mounts.