Factory PCM knock control discussion
01-01-2012, 09:15 PM
#53
hesitation is gone, but timing pull still occurs
Do I need to address the RPM Delta table?
RPM Delta Table = accelerator position Delta table? wouldn't be the first time cobb made a mistake.
"Acceleration Ignition Map - Ignition timing can also be corrected for a rapid change in the throttle opening rate for a smoother transition into wide open throttle."
Do I need to address the RPM Delta table?
RPM Delta Table = accelerator position Delta table? wouldn't be the first time cobb made a mistake.
"Acceleration Ignition Map - Ignition timing can also be corrected for a rapid change in the throttle opening rate for a smoother transition into wide open throttle."
Last edited by FazdaRX_8; 01-01-2012 at 09:54 PM.
01-18-2012, 01:23 PM
#55
Still happening.
This is on a new engine installed. I have thought about resetting the ecs again. I think the rpm delta uses the knock tables perticularly the increments and decrements and max. I made some minor adjustments but have not tested it.
This is on a new engine installed. I have thought about resetting the ecs again. I think the rpm delta uses the knock tables perticularly the increments and decrements and max. I made some minor adjustments but have not tested it.
01-18-2012, 02:18 PM
#60
hesitation is gone, but timing pull still occurs
Do I need to address the RPM Delta table?
RPM Delta Table = accelerator position Delta table? wouldn't be the first time cobb made a mistake.
"Acceleration Ignition Map - Ignition timing can also be corrected for a rapid change in the throttle opening rate for a smoother transition into wide open throttle."
Do I need to address the RPM Delta table?
RPM Delta Table = accelerator position Delta table? wouldn't be the first time cobb made a mistake.
"Acceleration Ignition Map - Ignition timing can also be corrected for a rapid change in the throttle opening rate for a smoother transition into wide open throttle."
01-18-2012, 05:36 PM
#62
I have been seeing logs that look just like mine, similar setup, and it has no timing pull, similar intake temps, g/s, and load. Maybe this only effects newish/healthy motors,
01-19-2012, 03:47 AM
#63
There is a knock learning strategy in the ecu and it looks just like what is implemented in every other Denso DBW ECU, right down to the values of certain parameters.
I'm not good enough with disassembly to understand exactly what, if anything, it is doing. However it doesn't seem like Cobb understood it well when they stopped working on the RX8, or for that matter even today on the Mazdaspeed cars.
So, there could be a knock learning table in ram affecting timing advance, and it wouldn't show up under the knock retard pid.
I'm not good enough with disassembly to understand exactly what, if anything, it is doing. However it doesn't seem like Cobb understood it well when they stopped working on the RX8, or for that matter even today on the Mazdaspeed cars.
So, there could be a knock learning table in ram affecting timing advance, and it wouldn't show up under the knock retard pid.
01-28-2012, 09:29 AM
#65
Analog datalogs?
It is a linear knock sensor, if you didn't see a signal then the sensor was broken or you didn't measure it correctly. More likely you thought it was a resonant knock sensor.
It is a microphone, and the response is linear throughout the audible range. If you can hear it, the knock sensor certainly can.
The Ecu filters knock from noise.
It is a linear knock sensor, if you didn't see a signal then the sensor was broken or you didn't measure it correctly. More likely you thought it was a resonant knock sensor.
It is a microphone, and the response is linear throughout the audible range. If you can hear it, the knock sensor certainly can.
The Ecu filters knock from noise.
01-28-2012, 03:45 PM
#67
This is how the knock retard value gets converted from a float to an unsigned integer for transmission over CAN.
This shows why no one ever logs knock retard.
I'm sure Team can explain the rest.
This shows why no one ever logs knock retard.
I'm sure Team can explain the rest.
01-28-2012, 07:09 PM
#69
I'm saying:
- We can't log rough or fine knock learning corrections.
- Turns out, we can't actually log knock retard either.
- The assertion that the knock sensor cannot hear detonation is ludicrous.
Linear/flat response knock sensors hear everything. The ECU then has to use filters and FFT analysis to discern knock from other noise. You can't just look at a scope trace and determine what the knock signal is, though you could with the old resonant knock sensors.
It is difficult for me to say exactly what the KR system is doing in practice. Racing Beat says the system is too sensitive. They may have been monitoring knock correction parameters in ram directly through the AUD port or mode 23.
You are seeing timing pulled, and it seems to me that knock correction is a potential cause that has been discounted by some for dubious reasons.
- We can't log rough or fine knock learning corrections.
- Turns out, we can't actually log knock retard either.
- The assertion that the knock sensor cannot hear detonation is ludicrous.
Linear/flat response knock sensors hear everything. The ECU then has to use filters and FFT analysis to discern knock from other noise. You can't just look at a scope trace and determine what the knock signal is, though you could with the old resonant knock sensors.
It is difficult for me to say exactly what the KR system is doing in practice. Racing Beat says the system is too sensitive. They may have been monitoring knock correction parameters in ram directly through the AUD port or mode 23.
You are seeing timing pulled, and it seems to me that knock correction is a potential cause that has been discounted by some for dubious reasons.
01-28-2012, 07:42 PM
#71
01-29-2012, 02:03 PM
#75
Oltman is looking at code, perhaps we can log major events but not minor events, but minor events can still pull timing?
If thats wrong, why dont u tell us exactly whats happening?
If thats wrong, why dont u tell us exactly whats happening?