Speed Density IPW Drop Out on 96530006 Patch
Nov 27, 2009, 11:51 AM
#17
OK, here are some logs showing the IPW issue, with the stock 0x162c value. A couple notes: this is running E-85 on 1250s. As I thought, the amplitude of the IPW jitter is a bit smaller than with my stock injectors, but the logs still clearly show the issue as well as I could slightly feel it.
Last edited by l2r99gst; Nov 27, 2009 at 11:55 AM.
Nov 27, 2009, 11:51 AM
#18
Here are the results with changing 0x162c to 255:
This seems to have worked!!!
The above are the absolute worst I saw in the log. The whole log was just way smoother. No jerking or hesitation. You can see the jitter is gone and just the normal 1 step in IPW here and there.
This seems to have worked!!!
The above are the absolute worst I saw in the log. The whole log was just way smoother. No jerking or hesitation. You can see the jitter is gone and just the normal 1 step in IPW here and there.
Last edited by l2r99gst; Nov 27, 2009 at 11:58 AM.
Nov 27, 2009, 12:08 PM
#22
Hey, John...thanks for getting this patch coded in the first place. A huge thanks to you, as always!
OK, I have to run and should be gone for the rest of the day. It would be good for others to test as I have to confirm or deny my claims.
Also, I would like to hear from mrfred on whether or not these results make sense, etc.
See you guys later,
Eric
OK, I have to run and should be gone for the rest of the day. It would be good for others to test as I have to confirm or deny my claims.
Also, I would like to hear from mrfred on whether or not these results make sense, etc.
See you guys later,
Eric
Nov 27, 2009, 01:16 PM
#23
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!
Nov 27, 2009, 01:18 PM
#24
Hey, John...thanks for getting this patch coded in the first place. A huge thanks to you, as always!
OK, I have to run and should be gone for the rest of the day. It would be good for others to test as I have to confirm or deny my claims.
Also, I would like to hear from mrfred on whether or not these results make sense, etc.
See you guys later,
Eric
OK, I have to run and should be gone for the rest of the day. It would be good for others to test as I have to confirm or deny my claims.
Also, I would like to hear from mrfred on whether or not these results make sense, etc.
See you guys later,
Eric
Eric, the flag I mentioned alters what formulas are used for some of the delta master load calculations for fuel pulse width generation, so even though master load is unchanged by the flag, it can still cause the jittery IPW. While I haven't looked with sufficient effort, I suspect that the jittery response is being caused by the code jumping back and forth between two different formulas for delta master load. Now that I now what effect 255 and 0 have on the IPW, I can more easily deduce exactly what is happening.
BTW, the Evo 9 has somewhat different code for selecting the value of the weighting parameter, but the same flag is generated at the end of the subroutine, so my thought is that the Evo 9 should be susceptible to this issue as well. I'll put together new patches over the next couple of days.
Nov 27, 2009, 02:27 PM
#28
For now, I think I'll just leave it to mrfred to create an official patch thread for it and the other affected ROMs. He's a lot more organized and knowledgable and there still may be additional parameters that are affected. It would be a good time to more completely document this section of the ROM too.
1 step closer to a master VIII ROM with no down falls and lots of options.
Thanks for all the expertise and testing in this thread!
I have wondered what that MAF reset was about for years.
Nov 27, 2009, 03:08 PM
#30
The first post (or second or third, if the OP is active any longer) in those threads with important information needs to be updated with issues, fixes to issues and/or other developments.
One of the only person that consistently does this is MRFRED with his How-tos, but even then some important info is still left lost in the depths of the thread.
Good thing on this thread is that the fix is in the first two pages. Most other threads arent that lucky.
