Fine Tuning Idle

[SSSTANG]

OK, I'm using Alpha-N Idle Fuel and had it idling great. But with the weather cooling off here, I decided to make changes to Coolant Temp Enrichment to get the AFR dead on, as the engine warms up. AFR was perfect yesterday, so I saved all changes. When I started it this morning AFR was very rich, 10-11.X, with the same settings as yesterday. I don't understand why it was perfect yesterday, and pig rich today. Target AFR is 14.7 at idle.

This is idle speed:



Alpha-N. It idles at 65 kPa:



Coolant Temp Enrichment. Ambient temp was 60° when I started it yesterday, so below 60° hasn't been tweaked:

[Danny Cabral]

Coolant Temperature Enrichment %. Ambient temp was 60° when I started it yesterday, so below 60° hasn't been tweaked:

Your pictures are too small. I enlarged them to their maximum size, and they're still too small.
Just tell us what the Coolant Temperature Enrichment % is at 60%. Is that 147% is see at 60°?
If so, that's too much Coolant Temperature Enrichment %. Even the base calibrations aren't that rich.

[SSSTANG]

Your pictures are too small. I enlarged them to their maximum size, and they're still too small.
Just tell us what the Coolant Temperature Enrichment % is at 60%. Is that 147% is see at 60°?
If so, that's too much Coolant Temperature Enrichment %. Even the base calibrations aren't that rich.

Yes, 147% at 60°.

I started by setting the idle at normal operating temperature. At 185-190°, idling at 975 , AFR is 14.7 with this Alpha-N.

After setting idle at normal operating temperature, I adjusted the Coolant Temperature Enrichment. At 60°, starting at 100% and continued bumping it up until AFR was 14.7, which happened at 147%.

When I restarted the engine this afternoon, 65° ambient, AFR was correct at 14.7 with Coolant Temperature Enrichment at 147%. Could it be the WBO2 sensor heating caused the initial rich condition?

[S2H]

You also have to take into consideration the ambient Air Temp Enrichment, and tune that table as well.

It's something most people overlook, and it's hard to get everything just right.
It will take more than just one day to get it correct. It may even take weeks of playing with it to dial it in.

[Danny Cabral]

After setting idle at normal operating temperature, I adjusted the Coolant Temperature Enrichment. At 60°, starting at 100% and continued bumping it up until AFR was 14.7, which happened at 147%.

That's not how to tune the Coolant Temperature Enrichment %. Look at the CL Comp %,
and add or subtract its percentage amount from the Coolant Temperature Enrichment % table.

Remember that 100% is the neutral value/factor; no modification added or subtracted to the Base Fuel Table.
Example: 120% adds 20%, and 90% subtracts 10%. So don't subtract the CL Comp % from 120, subtract it from 20.
If the Coolant Temperature Enrichment % is 130, and the CL Comp is −17%, you'd enter 125% in that cell (30 − 17% = 24.9).

Could it be the WBO2 sensor heating caused the initial rich condition?

The ECU doesn't display AFR or use WBO2 feedback, until the WBO2 sensor heating cycle is complete.

[SSSTANG]

You also have to take into consideration the ambient Air Temp Enrichment, and tune that table as well.
It's something most people overlook, and it's hard to get everything just right.
It will take more than just one day to get it correct. It may even take weeks of playing with it to dial it in.

I understand it takes time to get it right, going on day four with the Coolant Temperature Enrichment.

Example: 120% adds 20%, and 90% subtracts 10%. So don't subtract the CL Comp % from 120, subtract it from 20.
If the Coolant Temperature Enrichment % is 130, and the CL Comp is −17%, you'd enter 125% in that cell (30 − 17% = 24.9).

Can you explain that math?

[Danny Cabral]

Can you explain that math?

I did explain it, it's in the parenthesis of my last post.
Example: A common mistake is applying the CL Comp % to 130 (Coolant Temperature Enrichment %), however, it must be applied to 30.

[69cam]

Danny did explain it. I'll try to give you the 2 + 2 = 4 explanation. ;)

That's not how to tune the Coolant Temperature Enrichment %. Look at the CL Comp %...

I'm gonna go out on a limb here, and say that the CL Comp does not "COMPENSATE" for Coolant Temp Enrichment or Air Temp Enrichment. So as Danny said earlier, that 100% = neutral.

Example: 120% adds 20%, and 90% subtracts 10%. So don't subtract the CL Comp % from 120, subtract it from 20.

Another way to say it, is that 100% = NO FUEL ADDED OR SUBTRACTED.

If the Coolant Temperature Enrichment % is 130, and the CL Comp is −17%, you'd enter 125% in that cell (30 − 17% = 24.9).

Since we know that 100% = 0, the actual enrichment here is 30. Also, since we know now that the CL Comp is not going to adjust the fuel added from enrichment table, you need to do that math before you enter it on the table. So in the example provided, 130 was the magical number. If CL Comp as Danny stated, is removing -17% of the fuel, then you need to do the math to remove -17% of 30. 30 x 17% = 5.1 Now you need to take 5.1 away from 30. So in that example provided, you'd enter 130-5.1 = 124.9 or 125 for CLOSE ENOUGH.

[Danny Cabral]

Also, it's much easier to datalog this, and tune the Coolant Temperature Enrichment % while reviewing the datalog.
It's frustrating to try quickly tuning this, while the engine is running & warming up past each cell point on the table.

I find the most helpful datalog function, is overlaying the datalog on your Global Folder.
I'm in the habit of using the datalog Overlay feature every time I review a datalog.
Click on "Datalog" (on the top Toolbar), "Activate Overlay", then "Open Data Log".
You can literally "playback" a recorded event, and watch it as it happened on any screen.
Minimize (shrink) the datalog window, and move it to the bottom of any Global Folder screen.
Then click & scroll anywhere on the datalog, and watch it playback on your Global Folder (EFI software).
http://documents.holley.com/techlibr...9r10543rev.pdf (Holley EFI Datalogger Instructions)
http://forums.holley.com/showthread....s-amp-Datalogs (Datalog & System Log Information)

[S2H]

Something that can help with the tuning Process, is to make an air/fuel error Math Channel to review in your datalogs.

I use this one:
100*([AFR Left]-[Target AFR])/[Target AFR]
You can substitute in a fixed value for the Target AFR if you want, and you can do this with AFR Left or Right or average.
Whatever makes the most sense for your engine.
This returns a % difference so you can better push around the values.
I like to do about half or what the values say, and slowly move towards it being correct.
It takes a few times to get there, but it's much better than overshooting.

Remember, you're changing it by a percentage, not by actual numbers.
A value of 120% in the table, and WBO2s are reporting -10%, means
you need to be at 108 in the table (10% of 120 is 12, so 120-12=108).

You can push values around as you are already doing.
But it tends to overshoot some, so you have to go back, and lower the values a little when you are done.
Remember, it's really only exactly accurate at the exact temperature value.
Anything not the exact temperature value is blended with the cell next to it.
So you have to smooth the table a bit by hand, to get a nice fuel transition between all cells.

Also, your engine will respond differently as it warms up, due to the fact that while the water is the temperature we are measuring.
It doesn't account for fuel temperature, or for valve temperature, which all can make significant changes to fueling.
Also, barometric pressure can play into it as well, as well as humidity.

[Danny Cabral]

Remember, you're changing it by a percentage, not by actual numbers.

Yes, correct.

A value of 120% in the table, and WBO2s are reporting -10%, means
you need to be at 108 in the table (10% of 120 is 12, so 120-12=108).

No. In your example, it's −10% of 20, not 120. 100% is the neutral value/factor; no modification added or subtracted to the Base Fuel Table.
This would be 118% cell value entered in the Coolant Temperature Enrichment table (and a little lower, for reasons you mentioned below).

You can push values around as you are already doing.
But it tends to overshoot some, so you have to go back, and lower the values a little when you are done.
Remember, it's really only exactly accurate at the exact temperature value.
Anything not the exact temperature value is blended with the cell next to it.
So you have to smooth the table a bit by hand, to get a nice fuel transition between all cells.

This is exactly what I've experienced too, when tuning the Coolant Temperature Enrichment % table.
http://forums.holley.com/showthread....6335#post66335 (Additional Information)

[SSSTANG]

Thanks Danny, Scott & 69cam. Got it now. Will report back.

So Coolant Temperature Enrichment is working out well, until the temperature gets to somewhere between 125-130°, where AFR suddenly goes to 35:1. I was changing enrichment % as this was happening, and it had no effect. A blip of the throttle sends AFR to 11:1 and after a minute, settles down to 14.5:1. Closed Loop is inactive below 1100 RPM. Datalog was set for 60 seconds and I have two minutes, but missed the initial lean and also the blip of the throttle. I will get a better datalog tomorrow.

Update: Got it straightened out. At some point, Learn had taken fuel from the idle cells, so I added it back, enabled CL at idle, and readjusted Coolant Temperature Enrichment. Working on Acceleration Enrichment now. Any tips or advice?

[Danny Cabral]

At some point, Learn had taken fuel from the idle cells, so I added it back, enabled CL at idle, and readjusted Coolant Temperature Enrichment.

It's probably Fuel Table related, or the Learned Compensation Limits % (System ICF) need to be significantly decreased
in the problem area. If the Fuel Table is well tuned, the Learned Compensation Limits % should already be decreased.
I decreased my Learned Compensation Limits to 2% in the idle area. I left my Closed Loop Compensation Limits at 50%.

Working on Acceleration Enrichment now. Any tips or advice?

http://forums.holley.com/showthread....1379#post61379 (Related Acceleration Enrichment Thread)