Low RPM Lean Issue on 96531706
I know what you guys are saying. My tables have been very iterative. Adjust, test, adjust, test, repeat A LOT.
I have no doubt I could asjust the fuel control options avaliable to cover up the problems. Like I mentioned, as of right now, in closed loop, the only time it is an issue is when the car is in open loop and cold.
But my concern is just that there really is no reason for the step in the IPW and total sync FPW, yet it's there.
How about this, step aside from the actual driveability issue.
WHAT is causing the step in Total Sync FPW?
I have no doubt I could asjust the fuel control options avaliable to cover up the problems. Like I mentioned, as of right now, in closed loop, the only time it is an issue is when the car is in open loop and cold.
But my concern is just that there really is no reason for the step in the IPW and total sync FPW, yet it's there.
How about this, step aside from the actual driveability issue.
WHAT is causing the step in Total Sync FPW?
I'm going to open your log in LogWorks to be sure, but I think it may be because of the settings in the 'Ceiling Load vs RPM for Sync Load Accel/Decel Contributions' table.
I wonder if you change the lower RPM range to higher load values, if it fixes your problem. For example, change the 68, 68, 84, to 113.
Edit: I looked at your log and it looks like the sync accel FPW comes back in right about 1500 RPM, which is the next big jump in that table I mentioned. Any way you can post that table...have you changed it? Also, in your logs, is your load accurate or did LogWorks convert it down to 100% being max? I'm just curious because your load seems to be under the stock 68 ceiling load, but very close.
Last edited by l2r99gst; Jan 14, 2010 at 12:11 PM.
This table:
It is the ceiling load where sync accel or decel will take place vs. RPM. It's part of mrfred advanced fuel control thread. Try changing the first three values to something higher. I think that might be why your sync accel fpw is dropping out then coming back in.
If not, there are other controlling tables as well. If you haven't added them, go to the advanced fuel control thread and add all of those tables to your XML.
Also, when running SD, you should be changing your async accel vs TPS table (different table) when running SD to prevent leanness at throttle tip in.
It is the ceiling load where sync accel or decel will take place vs. RPM. It's part of mrfred advanced fuel control thread. Try changing the first three values to something higher. I think that might be why your sync accel fpw is dropping out then coming back in.
If not, there are other controlling tables as well. If you haven't added them, go to the advanced fuel control thread and add all of those tables to your XML.
Also, when running SD, you should be changing your async accel vs TPS table (different table) when running SD to prevent leanness at throttle tip in.
Last edited by l2r99gst; Jan 14, 2010 at 01:47 PM.
That table must have been added later as i have all the tables that were in Logic's original post. Would you post the definition?
That table looks VERY interesting though with respect to the issues I'm having.
My MAF tables are flat above 125Hz. MAF Comp is set to 128 from 125Hz up and the MAF characteristic scaling is set to 216 across the board. I did this to eliminate the non-linearity of the MAF scaling.
Before anybody says this is my problem, I have also tuned the car with completely stock MAF tables and had the same issue. This change however definitely lowered the loads I was seeing under low throttle conditions and is why that table L2r99gs-t posted has me very interested.
That table looks VERY interesting though with respect to the issues I'm having.
My MAF tables are flat above 125Hz. MAF Comp is set to 128 from 125Hz up and the MAF characteristic scaling is set to 216 across the board. I did this to eliminate the non-linearity of the MAF scaling.
Before anybody says this is my problem, I have also tuned the car with completely stock MAF tables and had the same issue. This change however definitely lowered the loads I was seeing under low throttle conditions and is why that table L2r99gs-t posted has me very interested.
Here you go. Here is that table and two others that are related.
The first table is the table that I posted. If uncompensated load goes over that number, sync accel/decel doesn't occur.
I have to look up what the 2nd and 3rd tables are. I know there are tables that define the minimum load change needed for sync accell/decl and ceiling values for each. I think these are the latter.
Edit: Just read mrfred's description. The 2nd and 3rd tables are simply the max values for deltamasterloadpos and deltamasterloadneg, respectively. I don't think I have the table defined yet for minimum change in load for sync accel/decel. I will look that up right now.
PHP Code:
<table name="Ceiling Load vs RPM for Sync Load Accel/Decel Contributions" category="Fuel" address="391e" type="2D" level="1" scaling="x54d16">
<table name="RPM" address="6576" type="Y Axis" elements="10" scaling="RPM"/>
</table>
<table name="Sync Load Accel DeltaMasterLoadPos Ceiling Value" category="Fuel" address="163a" type="1D" level="1" scaling="LoadMaster16"/>
<table name="Sync Load Decel DeltaMasterLoadNeg Ceiling Value" category="Fuel" address="163c" type="1D" level="1" scaling="LoadMaster16"/>
I have to look up what the 2nd and 3rd tables are. I know there are tables that define the minimum load change needed for sync accell/decl and ceiling values for each. I think these are the latter.
Edit: Just read mrfred's description. The 2nd and 3rd tables are simply the max values for deltamasterloadpos and deltamasterloadneg, respectively. I don't think I have the table defined yet for minimum change in load for sync accel/decel. I will look that up right now.
Last edited by l2r99gst; Jan 14, 2010 at 04:01 PM.
Here are the other two related tables. I just looked them up in IDA, so I could be wrong, but they are identical to 8859, so I think they're correct:
These tables are the min delta load needed for there to be a sync accel/decel to occur.
PHP Code:
<scaling name="LoadUncompDelta" units="Uncomp Load Change" toexpr="x*0.1862" frexpr="x/0.1862" format="%.1f" min="0" max="160" inc="1" storagetype="uint8" endian="big"/>
<table name="Min Uncomp Load Change at Steady Throttle for SyndLoadAccel/Decel Contribution" category="Fuel" address="3888" type="2D" level="1" scaling="LoadUncompDelta">
<table name="Uncompensated Load" type="Static Y Axis" elements="13">
<data>0</data>
<data>24</data>
<data>48</data>
<data>72</data>
<data>95</data>
<data>119</data>
<data>143</data>
<data>167</data>
<data>191</data>
<data>215</data>
<data>238</data>
<data>262</data>
<data>286</data>
</table>
</table>
<table name="Min Uncomp Load Change at Changing Throttle for SyncLoadAccel/Decel Contribution" category="Fuel" address="3895" type="2D" level="1" scaling="LoadUncompDelta">
<table name="Uncompensated Load" type="Static Y Axis" elements="13">
<data>0</data>
<data>24</data>
<data>48</data>
<data>72</data>
<data>95</data>
<data>119</data>
<data>143</data>
<data>167</data>
<data>191</data>
<data>215</data>
<data>238</data>
<data>262</data>
<data>286</data>
</table>
</table>
Last edited by l2r99gst; Jan 14, 2010 at 05:20 PM.
Sorry about that. Here you go:
PHP Code:
<scaling name="LoadMaster16" units="Uncomp Load" toexpr="x*0.1862" frexpr="x/0.1862" format="%.0f" min="0" max="160" inc="1" storagetype="uint16" endian="big"/>
<scaling name="x54d16" units="Uncomp Load" toexpr="x*54/16*0.1862" frexpr="x/(54/16*0.1862)" format="%.0f" min="0" max="160" inc="1" storagetype="uint8" endian="big"/>
Can you explain how you would change this? Decrease value to enrich? I heard about doing this but didn't know what it effected and how.
Yeah I read everything I just wasn't sure how sensitive it was, have any experience with how much it needs adjusted vs how bad off the AFR is? That's what I was looking for....
Is this the table?
Is this the table?
I find it interesting that most need to add acceleration enrichment on Async. My car goes very rich under TPS changes. I plan on pulling OUT Async enrichment.
I do want to point out something in my logs though. At the point of TPS change, and at the step in Sync pulse width, yes, there is acceleration enrichment. However, it fades away in a few samples and yet the Sync FPW doesn't change.
To me, that scream that it's still not an acceleration enrichment issue.
I do want to point out something in my logs though. At the point of TPS change, and at the step in Sync pulse width, yes, there is acceleration enrichment. However, it fades away in a few samples and yet the Sync FPW doesn't change.
To me, that scream that it's still not an acceleration enrichment issue.
I still think you should try out that 1st table.
Your log shows the sync accel fpw dropping out exactly in your lean spot, then when it comes back, your leanness goes away.
At least from your log, it looks to be the sync accel fpw dropping to 0 which is your problem.
Your log shows the sync accel fpw dropping out exactly in your lean spot, then when it comes back, your leanness goes away.
At least from your log, it looks to be the sync accel fpw dropping to 0 which is your problem.