Fuel Learn Table

[3 window]

Finally got the ignition advancing correctly. Now for another question. My Learn Table learns very quickly. About half a minute, maybe less, and the CL Comp is near zero. On the Learn Table, it's showing roughly -38 to -40 in those cells. I take it this is telling me the Fuel Table in these areas are roughly "equally rich", correct? I'd rather not make any changes to the Fuel Table, until after it drive it around a while and run it through the paces. Would there be any advantage to changing the map even though it's already leaned or would a change just make the ECU not have to compensate as much.

[Danny Cabral]

I take it this is telling me the Fuel Table in these areas are roughly "equally rich", correct?

The Learn Table is a modifier of the Base Fuel Table. These two tables actually function together as one, because the Learn Table values are directly applied to the Base Fuel Table. The Learn Table just indicates how much the Base Fuel Table has been altered (modified). The Base Fuel Table values don't change, unless you Transfer Learning To Base (which then allows you to blend the Fuel Graph so it's smooth). It's the Learn Table itself, that contains constantly changing values. When the Learn Table values stop making significant changes, the ECU is finished self-tuning. The purpose of the Learn Table is not to achieve similar values, high/low values (0% or 100%), or any value in particular. It's simply indicating the amount of tuning applied to the Base Fuel Table. Read this thread (LINK), that's what it's all about.
http://forums.holley.com/showthread....1842#post61842 (Learn Table - Diagnostic/Troubleshooting Tool)
http://forums.holley.com/showthread....5760#post45760 (Scroll down to "Learn Issues, Self-Tuning".)
Read the 4th & 5th paragraphs: http://forums.holley.com/showthread....2523#post62523 (Holley EFI Tuning Tips & Information)

I'd rather not make any changes to the Fuel Table, until after it drive it around a while and run it through the paces.

You don't necessarily ever have to "Transfer Learning To Base", unless you've reached the Learned Compensation Limits % or you want to blend in the entire Fuel Graph (fine-tuning). The ECU continuously updates and uses the Learn Table, regardless if you've "Transferred Learning To Base" or not. Clicking "Transfer Learning to Base" just updates the Base Fuel Table with the current Learn values (the engine doesn't know the difference), so you can blend the Fuel Graph for smooth transitions. Think of the Base Fuel Table and the Learn Table as one table, because the two actually function as one.
http://forums.holley.com/showthread....0150#post80150 ("Smooth" Function Information)
https://www.youtube.com/watch?v=y17MClF7SYA (Base Fuel Table/Fuel Graph Tuning - Part 1)
https://www.youtube.com/watch?v=aRn3A5_ecpo (Base Fuel Table/Fuel Graph Tuning - Part 2)

EFI Software Help Information/Instructions:
‒ On the top Toolbar, click "Help" & "Contents". This opens all Help topics.
‒ When navigating the software, click "Help ?", drag it to any parameter and click again.
..This automatically opens the definitions for that specific parameter.
‒ Tuning information can be read by clicking the F1 key, when you're viewing any screen.
http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual & Diagrams)
http://documents.holley.com/techlibrary_199r10544.pdf (Holley EFI Help/Instructions Overview)
http://documents.holley.com/techlibr...r10546rev1.pdf (Holley EFI Quick Start Guide)
http://forums.holley.com/showthread....ents-Read-This! (Initial Checks & Adjustments - Read This!)
Open the Holley EFI software "Help" Contents ("Help" drop down menu), and read "Step-By-Step Beginners Tuning".
Ensure the EFI software is set to run as an "Administrator" (right click for Properties/Advanced). Set it and forget it.

[3 window]

Makes good sense. Thanks.

[Danny Cabral]

Yep, just ensure the ECU doesn't reach its Closed Loop & Learned Compensation Limits % (in System Parameters).

[3 window]

I got ya. So if it has reached its limits (which I doubt it will), THEN I would have to remove fuel in those areas, because the ECU was not able to compensate enough prior to reaching the Compensation Limit %, correct?

[Danny Cabral]

So if it has reached its limits (which I doubt it will), THEN I would have to remove fuel in those areas, because the ECU was not able to compensate enough prior to reaching the Compensation Limit %, correct?

Yes, you can do that. However, you never have to actually edit the Base Fuel Table (unless there's a gross base calibration overestimation). You should "Transfer Learning To Base", and then blend the Fuel Graph for smooth transitions (as I described in post #2).

• If you'd like to manually tune the Base Fuel Table (even while the engine is running), read below:
Left click & drag to select a group of cells, then use the CTRL & Arrow keys (▲►▼◄) to change the highlighted cell values.
The ▲ & ▼ arrow keys adjust the Base Fuel Table slowly (one tenth at a time). The ◄ & ► arrow keys adjust it rapidly.
Or you can left click & drag a group of highlighted cells, and right click "Offset Selected" to adjust the entire cell group.
http://forums.holley.com/showthread....7531#post77531 (Closed Loop Datalog Tuning - Posts #2, #4 & #6)

• Afterwards, always ensure the Base Fuel Table is smooth by viewing the Fuel Graph. It's very important to have a smooth Fuel Graph.
One aspect of viewing the Fuel Graph: It's better to zoom in, by highlighting segments of the Base Fuel Table (left click & drag), and click "Graph".
This method offers much greater detail. Looking at the entire "Fuel Graph" will almost always look smooth, because it's not as magnified.
TIP: When the Fuel Graph is smooth, click "Conversion" (VE% Conversion mode) and continue smoothing the general contour of the VE Fuel Graph.
https://forums.holley.com/showthread...e-Tuning-Notes (EFI Idle Tuning Notes)
http://forums.holley.com/showthread....2523#post62523 (Holley EFI Tuning Tips & Information)

• Personally, I never use the "Smooth" button option. Manually blending the Fuel Graph smooth works much better.
http://forums.holley.com/showthread....0150#post80150 ("Smooth" Function Information)
https://www.youtube.com/watch?v=y17MClF7SYA (Base Fuel Table/Fuel Graph Tuning - Part 1)
https://www.youtube.com/watch?v=aRn3A5_ecpo (Base Fuel Table/Fuel Graph Tuning - Part 2)

• When the engine is tuned & running well, you should decrease the Closed Loop and Learned Compensation Limits % to lock in a good tune.
I decreased my Learned Compensation Limits to 2% in the idle area (10% elsewhere). My Closed Loop Compensation Limits are 50% or less.
When the Learn Table values stop making significant changes, the ECU is finished self-tuning.
http://forums.holley.com/showthread....7370#post47370 (Learn Table - Read this thread, especially posts #2, #6 & #11.)

• And if the Learned Compensation Limits % are significantly decreased (as they should be after the engine is tuned),
the Closed Loop Compensation can save the engine without skewing the Base Fuel Table.
So you can fix a temporary fuel system fault without necessarily having to fix the "tune".
http://www.yellowbullet.com/forum/sh....php?t=1000178 (Related Forum Thread)

[3 window]

When and/or how often do you recommend Transfer Learning to Base? I think my idle is pretty well Learned, seeing that I'm at 0% correction during normal operating temps. Should I wait until the cruise & WOT portions have Learned as well?

[Danny Cabral]

Should I wait until the cruise & WOT portions have Learned as well?

Yes, so you only have to blend the Fuel Graph once.

EFI Software Help Information/Instructions:
‒ On the top Toolbar, click "Help" & "Contents". This opens all Help topics.
‒ When navigating the software, click "Help ?", drag it to any parameter and click again.
..This automatically opens the definitions for that specific parameter.
‒ Tuning information can be read by clicking the F1 key, when you're viewing any screen.
http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual & Diagrams)
http://documents.holley.com/techlibrary_199r10544.pdf (Holley EFI Help/Instructions Overview)
http://documents.holley.com/techlibr...r10546rev1.pdf (Holley EFI Quick Start Guide)
http://forums.holley.com/showthread....ents-Read-This! (Initial Checks & Adjustments - Read Steps #1-#6!)
Open the Holley EFI software "Help" Contents ("Help" drop down menu), and read "Step-By-Step Beginners Tuning".
Ensure the EFI software is set to run as an "Administrator" (right click for Properties/Advanced). Set it and forget it.

[3 window]

Again, many thanks.

[Rick90lx]

Danny, once the system has Learned and you start lowering the amount if Closed Loop Compensation %, should you also lower the Learned Compensation Limits %? I ask because my Closed Loop Compensation Limits were at 100% in boost, and the Learned Compensation Limits were defaulted at 150%. That never made much sense to me.

[Danny Cabral]

Danny, once the system has Learned and you start lowering the amount if Closed Loop Compensation %, should you also lower the Learned Compensation Limits %?

1)
Yes. After Learning has finished self-tuning all areas of the Fuel Table, the Closed Loop and Learned Compensation Limits should be decreased.

• Idling: Once the Learning has finished self-tuning the Base Fuel Table, enter the Learn Parameters and decrease the Learned Compensation Limits % down to around 2% in the idle area. The reason why is, the idle can go through repeated 'cycles of Closed Loop compensation' (+/−). When you're idling for a long period of time, the electric fans are regulating the cooling system temperature between 200° & 190°. This temperature variance can cause the Closed Loop to add & subtract a significant amount of fuel (as it should), especially if the fans are powerful & blowing hot air at the throttle body. However, you don't want the Learn Table to constantly modify the Base Fuel Table with these temporary corrections. If you shut off the engine during the lean end of the "cycle", the Learn Table has self-tuned the idle area as such, and may run momentarily lean on the next startup. Closed Loop is not saved, so it's allowed to constantly fine-tune the AFR. Learning is saved (and its values modify the Base Fuel Table), so it should be limited once the engine is tuned.

• Learning: Once the Learning has finished self-tuning the Base Fuel Table, enter the Learn Parameters and decrease the Learned Compensation Limits % down to around 10% (or less) in the entire table (except idle - 2%). The reason why is, if the WBO2 sensor fails, you don't want a significant amount of WBO2 correction happening, because it will then corrupt the Learn Table with false values. After the defective WBO2 sensor is replaced, the Learn Table would have to be cleared and the Learning starts all over again (if the Learning wasn't Transferred to Base recently). This can be avoided by decreasing Compensation Limits down to around 10% (or less). Remember, the Closed Loop isn't saved, so there's no corruption there. But the Learn Table is saved (and its values modify the Base Fuel Table), so limit its compensation once the engine is tuned. Of course, the Closed Loop Compensation Limits % can also be decreased once the Learning has self-tuned the engine.

I ask because my Closed Loop Compensation Limits were at 100% in boost, and the Learned Compensation Limits were defaulted at 150%. That never made much sense to me.

2)
• At first, the ECU needs those Compensation Limits set high, so it can make significant tuning
adjustments. Some base calibrations are farther from ideal than others, but the Closed Loop &
Learn Table will tune it right. Initially, the ECU just needs to be allowed to do the most it can.

• The Target A/F Ratio Table is the "commander". Everything (WBO2 sensor, Closed Loop operation, Learn
Table, Base Fuel Table, etc.) works off of it to maintain the programmed AFR, so it must be right. After
the EFI system is initially tuned, changes can still be made to the Target A/F Ratio Table, and (before
exiting the TAFR screen) you have the option of automatically adjusting the Fuel Map. It's a great feature.

• Closed Loop functions off of the WBO2 sensor.
Learning functions off of the Closed Loop Comp operation.
Which is why Closed Loop must be active for Learning to occur.

• The Base Fuel Table doesn't change its displayed values unless you Transfer Learning To Base.
However, it is always in a modified state because the Learn Table values are applied to it.
Closed Loop and Learning happens in "real time", but only the Learning is saved (Learn Table).

[Rick90lx]

Thanks again for taking the time, that makes a lot of sense. I was reluctant to start reducing it, but I learned a few things about how much fuel I should be commanding. The Learn Table now shows -1% or -2%, instead of adding anywhere which makes me feel a lot safer.

[FordTBI]

Relative to Learn Table; which cell shows more learning (2.2) or (-1.6). Also, would the entire table need to read similar cell readings to be considered Learned, and therefore able to have the Learned Compensation Limits % reduced? Thanks, Jim

[Danny Cabral]

Relative to Learn Table; which cell shows more learning (2.2) or (-1.6).

It depends on the Base Fuel Table value in that cell. The Learn Table can still indicate a negative number while adding fuel.
Example: A Learn Table value of −20, changing toward −10, is adding fuel (even though both numbers are negative values).
Example: A Learn Table value of 20, changing toward 10, is subtracting fuel (even though both numbers are positive values).

Also, would the entire table need to read similar cell readings to be considered Learned...

The purpose of the Learn Table is not to achieve similar values, high/low values (0% or 100%), or any value in particular.
It's simply indicating the amount of tuning applied to the Base Fuel Table. Read this thread, that's what it's all about.

...and therefore able to have the Learned Compensation Limits % reduced?

When the Learn Table values stop making significant changes, the ECU is finished self-tuning.
You can then Transfer Learning To Base (which clears the Learn Table), and blend the Fuel Graph smooth.
When the engine is tuned & running well, you should decrease the Closed Loop and Learned Compensation Limits % to lock in a good tune.
I decreased my Learned Compensation Limits to 2% in the idle area (10% elsewhere). My Closed Loop Compensation Limits are 50% or less.

EFI Software Help Information/Instructions:
‒ On the top Toolbar, click "Help" & "Contents". This opens all Help topics.
‒ When navigating the software, click "Help ?", drag it to any parameter and click again.
..This automatically opens the definitions for that specific parameter.
‒ Tuning information can be read by clicking the F1 key, when you're viewing any screen.
http://documents.holley.com/techlibr...10555rev17.pdf (Holley EFI Wiring Manual & Diagrams)
http://documents.holley.com/techlibrary_199r10544.pdf (Holley EFI Help/Instructions Overview)
http://documents.holley.com/techlibr...r10546rev1.pdf (Holley EFI Quick Start Guide)
http://forums.holley.com/showthread....ents-Read-This! (Initial Checks & Adjustments - Read This!)
Open the Holley EFI software "Help" Contents ("Help" drop down menu), and read "Step-By-Step Beginners Tuning".
Ensure the EFI software is set to run as an "Administrator" (right click for Properties/Advanced). Set it and forget it.

[FordTBI]

Danny, relative to the Learn Table, which cell shows more Learning (2.2) or (-1.6). But apparently I'm not communicating effectively. I've read all of the documents available from Holley and referenced, by you & others on this forum, but have been unable to find an answer, that I can reconcile to this question. I fully understand that the Learn Table modifies the Base Fuel Table. "The values reveal “self-tuning” that occurred on specific cells. The numbers reflect an offset percentage that is applied to the Base Fuel Table in order to comply with the Target A/F Ratio (Fuel ICF Definitions - Learn Table Help section). This would indicate to me that the smaller the numerical value (either + or -) the less modification and therefore the more Learned. Correct? Yes or no?

If the answer is yes, then, it appears to me, the goal would be to have the entire Learn Table populated with similarly low numeric values to show a completed self-tuned Fuel Table. Yes or no?

From my readings, I suspect this is not possible. I suspect that is why you qualified your answer, "When the Learn Table values stop making significant changes, the ECU is finished self-tuning." However, I've been unable to locate a document that will, define "significant changes". Are we talking a decimal point, 1 or 2 whole numbers, what?

I appreciate your comment as to your Closed Loop & Learned Compensation Limits. It gives a guideline (something I've not been able to find in any of Holley's documents) for a novice to follow.

A follow-up question I have. Have you found that a locked-in tune prevents intermittent and spurious driveability issues? Thanks for your time & help.