Speed Density IPW Drop Out on 96530006 Patch
Nov 27, 2009, 03:25 PM
#31
I just tried this fix. Got the car out. Drove a few miles in the problem range. Pulled over and reflashed just this change. Got back on the road and drove another 10 miles or so, deliberately trying to keep the car in the 1800-2500 rpm range.
The difference is NIGHT AND DAY!!!! I notice the difference in every gear, especially at very low parking lot speeds. I didn't even realize how much it was compromising drivability as I've only run my current cams (BF272s) with SD. What I attributed to the larger cams was just the exagerration of the SD jitter. The jitter wasn't as big of a deal with my old 280 cams (which I drove with both the MAF and in SD), but it really was a big deal with these race cams. I just didn't realize it until it was fixed.
Thanks a bunch for figuring this out!
The difference is NIGHT AND DAY!!!! I notice the difference in every gear, especially at very low parking lot speeds. I didn't even realize how much it was compromising drivability as I've only run my current cams (BF272s) with SD. What I attributed to the larger cams was just the exagerration of the SD jitter. The jitter wasn't as big of a deal with my old 280 cams (which I drove with both the MAF and in SD), but it really was a big deal with these race cams. I just didn't realize it until it was fixed.
Thanks a bunch for figuring this out!
Thanks
..I can't wait to revisit SD.
Nov 29, 2009, 04:28 PM
#38
I'll give this a test tomorrow as well. Great work guys, I don't know where the Evo community would be right now if it wasn't for all the hard work you guys pour into this stuff. I really wish I was able to help out with disassembly, but me trying to figure that stuff out at the moment is like trying to figure out what women want lol.
Nov 29, 2009, 06:54 PM
#41
It works! It works! At cruise, at any speed (specifically 1800-2800rpm) the car drives SMOOTH AS SILK! I will be logging over the next few days to verify nothing else is changed but I'm confident that this was something that only affected airflow levels at cruise.
Thank you mrfred, I'm SO HAPPY!
Thank you mrfred, I'm SO HAPPY!
Nov 29, 2009, 07:03 PM
#42
IX's do in fact do the same thing. It was something I thought I was going to have to live with and go from there. Some ROMs are a little less prone (the 94170015 and 8859) than others but the 9653 is so bad I have swapped 05s to 03-04 computers to get rid of the issue...or at least lessen it.
Nov 29, 2009, 07:59 PM
#43
IX's do in fact do the same thing. It was something I thought I was going to have to live with and go from there. Some ROMs are a little less prone (the 94170015 and 8859) than others but the 9653 is so bad I have swapped 05s to 03-04 computers to get rid of the issue...or at least lessen it.
Nov 29, 2009, 11:54 PM
#44
I've been through the subroutine in the 9653 and 8859 ROMs that determines the weighting factor for the running master load average. After looking at both subroutines, its become clear that setting the over/under value to 255 will fix the low rpm stutter, but it will limit the load-based acceleration enrichment under light-to-moderate load conditions, so this may not be the best solution.
I have found another way to stop the low load stuttering while still allowing the standard range of load-based acceleration enrichment.
1) Add the following table to your xml file:
9653 ROMs:
<table name="Scaling Factor for Transition Load" category="Speed Density Programming" address="1630" type="1D" level="1" scaling="uint16"/>
8859XX15 ROMs:
<table name="Scaling Factor for Transition Load" category="Speed Density Programming" address="1230" type="1D" level="1" scaling="uint16"/>
2) The value in this table should be 112. Change it to 0.
3) Set "MAF Pulse Width Reset" back to the stock value of 205.
Let me know how that works.
I have found another way to stop the low load stuttering while still allowing the standard range of load-based acceleration enrichment.
1) Add the following table to your xml file:
9653 ROMs:
<table name="Scaling Factor for Transition Load" category="Speed Density Programming" address="1630" type="1D" level="1" scaling="uint16"/>
8859XX15 ROMs:
<table name="Scaling Factor for Transition Load" category="Speed Density Programming" address="1230" type="1D" level="1" scaling="uint16"/>
2) The value in this table should be 112. Change it to 0.
3) Set "MAF Pulse Width Reset" back to the stock value of 205.
Let me know how that works.
Last edited by mrfred; Nov 30, 2009 at 09:07 AM.
