RomRaider

I've found what appears to be a knock sum for the 32-bit ECU. This variable (1 byte) is incremented by 1 at the start of each knock event as determined by the knock signal. It is only incremented if the knock signal was clear during the previous execution. As an example, it would look something like this:

(KS = knock signal)
KS CLEAR ; COUNTER = 0
KS SET; COUNTER = 1
KS SET; COUNTER = 1
KS CLEAR; COUNTER = 1
KS CLEAR; COUNTER = 1
KS SET; COUNTER = 2
KS CLEAR; COUNTER = 2
KS SET; COUNTER = 3

So, basically, the counter is incremented at the first knock event in each continuous pattern of knock (or if only a single knock event occurs). When the counter reaches 35 it resets to zero. Anyway, I'll be adding this to the next logger def update -> maybe it will be useful.

May I request for the address of this variable in the A2ZJC00G 2.0 LGT ROM? I would be keen to observe this.

I'll be adding to the next logger defs for all 32-bit ECUs.

Very cool. Does the reset at 35 tie into a change in IAM or something like that?

The handiest feature about this parameter is that we can use it instead of logging any of the timing and knock parameters. Since we have access to our tables, we could just log total timing and the counter which appears to be 1 byte. If we are very familiar with our ecu and the compensations, we probably don't even need to log total timign.

I checked it against what I thought was knock and it correlates 100% so far so I don't think experienced tuners will see anything different.

It will definitely help noobs though. It's fairly difficult to distinguish knock that causes FLKC to update. In the past, we had to keep track of the FLKC table and check it against when it changed. Now, we no longer have to do that.

No, it is just an arbitrary limit. The knock sum is not actually used by the ECU as far as I can tell.

Interesting... What's the counter update rate? It's like crank degree, 1 rev? Or not related to to engine speed, just code execution cycle?

It would update as often as the block of routines is executed, which includes FBKC/FLKC/IAM determination.

Knock sum is great. I actually heard knock yesterday and saw the knock sum go up 2 points and then FBKC and FLKC kicked it down. Very nice to see it. Holy crap my car knocks at idle. Prolly should find those bolts I dropped under the intake manifold and fix my exhaust leak. It is probably setting it off. Or it is tip in related.

Knock sum is going to be available to all 32bit owners with the next def release, right?

It is already in the latest logger defs for all applicable 32-bit ECUs. Not every ECU has the knock sum.

I totally missed the fact that you released defs this month.

Do you have a list going?

I can't seem to find it on my 05 STi (A2ZJB11J).

So what's it mean when I have either 1) a change to Knock Sum (KS) but no change to IAM, FLKC, or FKBC or 2) when I have a change to IAM, FLKC, or FBKC, but no change to KS?

For number 1, I'm guessing that it means that your ecu detected knock but it chose to ignore it due to the tuning parameters.

I have not seen #2 occur.

EDIT: Actually, I've seen FLKC change due to moving from one FLKC cell to another.