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I put two instances of spark knock retard events below. I did not include what the log shows for spark advance because it is only the "effective timing" after the ECM takes all various tables into account. I still don't know anything about adaptive knock, or how anything else affects the spark knock retard I'm seeing in the logs.
I took a look at my log, particularly a section where I had the cruise control set to 75 mph in 6th gear and had spark knock retard for the entire duration.
467 consecutive data points
Constant 2.25 degrees front spark knock retard
Constant 1.75 degrees rear spark knock retard
RPM: 2935 average
MAP: 60 kPa average
Throttle position: 22% average
Set lambda: .982
VE front: 93 average
VE rear: 91 average
O2 mV Front: 669mV (.997 lambda) (14.64 A/F) AVERAGE
O2 mV Rear: 559mV (.998 lambda) (14.65 A/F) AVERAGE
A separate instance of spark knock retard to look at:
Cruising at 57-61 mph, constant spark knock retard
35 consecutive data points
Constant 2.25 degrees front spark knock retard
Constant 1.75 degrees rear spark knock retard
RPM: 2740 average
MAP: 54 kPa average
Throttle position: 19% average
Set lambda: .982
VE front: 94 average
VE rear: 93 average
O2 mV Front: 714mV (.996 lambda) (14.62 A/F) AVERAGE
O2 mV Rear: 635mV (.997 lambda) (14.64 A/F) AVERAGE
I put two instances of spark knock retard events below. I did not include what the log shows for spark advance because it is only the "effective timing" after the ECM takes all various tables into account. I still don't know anything about adaptive knock, or how anything else affects the spark knock retard I'm seeing in the logs.
I took a look at my log, particularly a section where I had the cruise control set to 75 mph in 6th gear and had spark knock retard for the entire duration.
467 consecutive data points
Constant 2.25 degrees front spark knock retard
Constant 1.75 degrees rear spark knock retard
RPM: 2935 average
MAP: 60 kPa average
Throttle position: 22% average
Set lambda: .982
VE front: 93 average
VE rear: 91 average
O2 mV Front: 669mV (.997 lambda) (14.64 A/F) AVERAGE
O2 mV Rear: 559mV (.998 lambda) (14.65 A/F) AVERAGE
A separate instance of spark knock retard to look at:
Cruising at 57-61 mph, constant spark knock retard
35 consecutive data points
Constant 2.25 degrees front spark knock retard
Constant 1.75 degrees rear spark knock retard
RPM: 2740 average
MAP: 54 kPa average
Throttle position: 19% average
Set lambda: .982
VE front: 94 average
VE rear: 93 average
O2 mV Front: 714mV (.996 lambda) (14.62 A/F) AVERAGE
O2 mV Rear: 635mV (.997 lambda) (14.64 A/F) AVERAGE
Brandon
What do you think a knock event is? The adaptive knock tables as there is two of them in your bike should be set to "0" while you are developing a tune. These table control how much learned spark retard get applied. So for tuning purposes only you want it turn off so you can see what's currently going on and adjust for it properly.
What do you think a knock event is? The adaptive knock tables as there is two of them in your bike should be set to "0" while you are developing a tune. These table control how much learned spark retard get applied. So for tuning purposes only you want it turn off so you can see what's currently going on and adjust for it properly.
Steve, thanks for taking the time to help me learn.
Now that you ask that, I'm starting to see I may not be tuning in the correct sequence... I've been reminded of the other factors that could cause knocking: temperature, leaner than expected AFR (via incorrect VE tables, an intake manifold gasket leak, dirty injectors, etc.), or even a defective knock sensor.
My understanding of a knock event is when there is pre-detonation sensed by the knock sensor. That is to say the fuel detonates (combusts) prior to TDC and causes compression to rise too rapidly.
My understanding of a spark knock retard event is when the knock sensor senses knock (say that five times fast) and retards (delays) the spark so the fuel detonates at the appropriate time (TDC).
Back to one of my original questions. Do I even need to worry about spark timing if the ECM is going to automatically correct for knock?
I will have to look at those adaptive spark tables when I get home, assuming I can even see them in Powercore.
Essentially, I need to 'disable' adaptive spark by setting the table values to zero, log data, and THEN look for spark knock retard events in data.
With the adaptive spark tables 'enabled' with their current learned values, the spark knock retard events I'm seeing in the logs may just be the learned values and not real spark knock events?
I put two instances of spark knock retard events below. I did not include what the log shows for spark advance because it is only the "effective timing" after the ECM takes all various tables into account. I still don't know anything about adaptive knock, or how anything else affects the spark knock retard I'm seeing in the logs.
I took a look at my log, particularly a section where I had the cruise control set to 75 mph in 6th gear and had spark knock retard for the entire duration.
467 consecutive data points
Constant 2.25 degrees front spark knock retard
Constant 1.75 degrees rear spark knock retard
RPM: 2935 average
MAP: 60 kPa average
Throttle position: 22% average
Set lambda: .982
VE front: 93 average
VE rear: 91 average
O2 mV Front: 669mV (.997 lambda) (14.64 A/F) AVERAGE
O2 mV Rear: 559mV (.998 lambda) (14.65 A/F) AVERAGE
A separate instance of spark knock retard to look at:
Cruising at 57-61 mph, constant spark knock retard
35 consecutive data points
Constant 2.25 degrees front spark knock retard
Constant 1.75 degrees rear spark knock retard
RPM: 2740 average
MAP: 54 kPa average
Throttle position: 19% average
Set lambda: .982
VE front: 94 average
VE rear: 93 average
O2 mV Front: 714mV (.996 lambda) (14.62 A/F) AVERAGE
O2 mV Rear: 635mV (.997 lambda) (14.64 A/F) AVERAGE
See where your measured is leaner than your desired?
Try bumping your VE up in that area a few points and see if it effects your knock event.
I believe M8's use a different strategy when it comes to timing and you won't get to where there are no spark events as long as it's just a few degrees the ECM is doing it's job, at least that's how I understand it, Maybe Steve or Rigid could explain it better
Just remember that retard reported from the ECM is just what happened at the time it was requested. So let say the ECM decides it needs to pull 5 deg out, do you think about what it has to do once its pulled? If you cannot get at adaptive knock retard your basically screwed. The adaptive retard may take as much as 500 miles to learn back out again. So is what your seeing real knock at that time or is it adaptive learned knock from before?
Just remember that retard reported from the ECM is just what happened at the time it was requested. So let say the ECM decides it needs to pull 5 deg out, do you think about what it has to do once its pulled? If you cannot get at adaptive knock retard your basically screwed. The adaptive retard may take as much as 500 miles to learn back out again. So is what your seeing real knock at that time or is it adaptive learned knock from before?
Argh…so much crap.
I’ve already ridden over 500 miles since loading the FM tune, but I’ve done several “auto” tunes in that time. I’ll leave it be for now and just ride.
I can ride 500 miles commuting in a week and it’s 75F this week so I’ll get that out of the way
Last edited by BrandonSmith; 02-20-2024 at 06:11 PM.
Just remember that retard reported from the ECM is just what happened at the time it was requested. So let say the ECM decides it needs to pull 5 deg out, do you think about what it has to do once its pulled? If you cannot get at adaptive knock retard your basically screwed. The adaptive retard may take as much as 500 miles to learn back out again. So is what your seeing real knock at that time or is it adaptive learned knock from before?
@Steve Cole ok, Powercore software doesn't show adaptive knock control, but the older WinPV software does...
02-20-2024, 12:30 PM
