Cylinder airmass drops suddenly WOT in boost
06-19-2019, 04:10 PM
#61
Yeah the air mode patch just fixes the air calc not returning to normal when running in speed density "backup" mode and has nothing to do with what is happening. I would find an ECM/OS that has the enhancement for 2 bar SD and use that for starters. I'm not surprised an 09 suburban OS doesn't have it available so maybe just use the 13 E38 or reflash the 09 to a truck OS first with an MDI so it does all segments.
06-21-2019, 10:30 PM
#63
I bet "fast exit torque" under Torque Management was responsible for the timing reduction you observed as that's the only non-shift related torque management I have enabled (says "use spark- enabled" ).
Aside from the 1 degree of burst knock I still have enabled.
I'll log torque management pids to see but the tune wasn't finished anyways due to trying to figure out the airmass drop, so I didn't spend my time analyzing any timing reduction.
Also. Looking at the 09 stock vs modified tune, I didn't alter anything under the "Torque Model" section. Desired throttle area was also left stock, only the "Area rate limits" section of Electronic Throttle was adjusted.
Nothing in the Transients tab was changed either.
P0101, P0106 and P0121 tests in Engine Diag--> airflow---> have been disabled via a min etc setting of 257°F
Engine Diag--> airflow---> airflow correlation--> P0068 test was also disabled via an enable rpm of 8000 rpm (the related tables below it were untouched as I'm assuming the 8000 rpm entry acts as a master disable switch).
Going to try the 09 ecu tomorrow or soon with the stock prediction coefficients, should be interesting
Just in case the issue is related to the MAF table somehow being referenced, I will also see if the issue happens when I put maf values back into the maf table.
*My maf values are all zeros after the 1st two frequencies as an obvious way to tell if I'm in VE only mode if it runs. However this may be causing the issue we see here although I never had an issue with any gen 3 setups with that technique.
Time will tell with more experimenting.
Another possible area of concern if dbw pedals are related to the issue is that the owner is using a 2013 pedal with the 09 ecu. The 2013 dbw pedal was used the entire time though since the swap was completed. The owner tried his 2009 pedal at first but it didn't show any accelerator pedal position % so the 2013 one was swapped in and pedal movement was restored. He's using the 2009 engine harness and associated wiring.
Aside from the 1 degree of burst knock I still have enabled.
I'll log torque management pids to see but the tune wasn't finished anyways due to trying to figure out the airmass drop, so I didn't spend my time analyzing any timing reduction.
Also. Looking at the 09 stock vs modified tune, I didn't alter anything under the "Torque Model" section. Desired throttle area was also left stock, only the "Area rate limits" section of Electronic Throttle was adjusted.
Nothing in the Transients tab was changed either.
P0101, P0106 and P0121 tests in Engine Diag--> airflow---> have been disabled via a min etc setting of 257°F
Engine Diag--> airflow---> airflow correlation--> P0068 test was also disabled via an enable rpm of 8000 rpm (the related tables below it were untouched as I'm assuming the 8000 rpm entry acts as a master disable switch).
Going to try the 09 ecu tomorrow or soon with the stock prediction coefficients, should be interesting
Just in case the issue is related to the MAF table somehow being referenced, I will also see if the issue happens when I put maf values back into the maf table.
*My maf values are all zeros after the 1st two frequencies as an obvious way to tell if I'm in VE only mode if it runs. However this may be causing the issue we see here although I never had an issue with any gen 3 setups with that technique.
Time will tell with more experimenting.
Another possible area of concern if dbw pedals are related to the issue is that the owner is using a 2013 pedal with the 09 ecu. The 2013 dbw pedal was used the entire time though since the swap was completed. The owner tried his 2009 pedal at first but it didn't show any accelerator pedal position % so the 2013 one was swapped in and pedal movement was restored. He's using the 2009 engine harness and associated wiring.
Last edited by foxsl; 06-21-2019 at 11:24 PM.
06-25-2019, 08:55 PM
#68
Yes so far it seems like either of those are the culprit. Scanning the Air Calc Mode pid shows it bouncing back and forth from high speed to normal to unknown modes...however when it does the back and forth in other areas it doesn't show any change so that may be fine. I only mention it as someone on a tuning forum mentioned Hi Speed is maf mode, not sure how correct that is though.
06-26-2019, 09:00 AM
#70
In total I've tried the 09 ecu at first with prediction coefficients zero'd out and maf curve zero'd out, then the 2013 ecu with and without coeffcients zerod out as well as the maf curve zero'd out, and now back to the 2009 e38 ecu with coefficients as stock and maf curve back into it.
Yes so far it seems like either of those are the culprit. Scanning the Air Calc Mode pid shows it bouncing back and forth from high speed to normal to unknown modes...however when it does the back and forth in other areas it doesn't show any change so that may be fine. I only mention it as someone on a tuning forum mentioned Hi Speed is maf mode, not sure how correct that is though.
Yes so far it seems like either of those are the culprit. Scanning the Air Calc Mode pid shows it bouncing back and forth from high speed to normal to unknown modes...however when it does the back and forth in other areas it doesn't show any change so that may be fine. I only mention it as someone on a tuning forum mentioned Hi Speed is maf mode, not sure how correct that is though.
06-26-2019, 01:24 PM
#71
I've been slammed and haven't been on here much or had time to look at anything but I zero out the MAF table all of the time when things are in SD and never had this problem before so I highly doubt that's it. The air calc mode usually bounces around quite a bit but hi speed is definitely not MAF mode because if it was it wouldn't run at all and I see that all of the time in SD. Hopefully it just stays good now!