SC Tuner Software Question

fastsc92

Registered User
My member account still hasn't been activated yet( it's been almost 4 months....) so I'll have to post my question here for now.


I'm running the SC Tuner software from SCTuner.net with an EEC tuner board. While its not the best stuff out there, it works fine for me. I have a quick question regarding the fuel tables.

I'm confused about how they are labeled. There is a Base Fuel Table....and a stabilized base fuel table. Which one controls CL and OL? I was thinking that the Base Fuel does CL and the stablized does OL.

However....

The Tweecer software for mustangs labels their tables as:
Base OL (Values vary with load)
Stabilized Closed Loop (Contains all values of 14.6)


The EEC Tuner Software (Text Editor) lables the tables as:
Base Fuel Table
Stabilized OL

So my question is, which table controls OL and CL in the SCTuner software?
 
Mustangs handle load in a different way than SC's so don't be confused by what they use. In our case the base table is used mainly during cold start to warm up conditions. Notice the low load AFR is richer (than the stabilized table) whereas the high load is leaner. Both tables are used in open loop based on engine temp and time running. 90% of the time you will be running on the OL stabilized table.

Also notice that the base fuel table is normalized by load and ECT leaving it totally independent of RPM whereas the OL table is normalized by load and rpm which is much more appropriate for normal operating temperature use.

For closed loop the car will always run 14.64 AFR. You can shift the closed loop AFR slightly by changing the closed loop bias if say you wanted to run a little leaner than 14.64.
 
I'm completely going through my tune again this year with much better results. At one time I was told to scale my displacement and MAF tables. The car ran great, but had a hard time idling.

This year I re-did everything so that I have the correct displacement and injector values and tuned my own transfer function. The result is smooth idling and dashpot controls. I always primarily tuned the stabilized table and got what I commanded for a ratio.

Would it be safe to tune the base table to 14.6 for all or the majority of the values since it's primarily referenced under closed loop? When does it actually switch from the base table to the stabilized table if they are both used under OL? This is what I have so far:

Base Fuel:

14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004
14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004
14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004
14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004
14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004
13.11722 13.00316 12.8891 13.23128 13.00316 12.8891 12.66097 12.66097 12.66097 12.43285
12.09066 12.09066 12.09066 12.31878 12.31878 12.31878 12.31878 12.31878 12.31878 12.31878
11.97659 11.97659 11.97659 11.97659 12.09066 12.09066 12.09066 12.09066 12.09066 12.09066

Stabilized Fuel:
13.57347 13.8016 14.25785 14.37191 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004
13.91566 14.14379 14.25785 14.48598 14.60004 14.60004 14.60004 14.60004 14.60004 14.60004
14.60004 14.60004 14.60004 14.60004 14.60004 14.48598 14.37191 14.25785 14.14379 14.02972
14.60004 14.60004 14.60004 14.48598 14.37191 14.25785 14.14379 13.91566 13.8016 13.57347
14.60004 14.48598 14.37191 14.25785 14.02972 13.8016 13.57347 13.34535 13.11722 12.77503
13.11722 13.00316 12.8891 13.23128 13.00316 12.66097 12.54691 12.54691 12.66097 12.43285
12.09066 12.09066 12.09066 12.31878 12.31878 12.43285 12.43285 12.31878 12.31878 12.09066
11.97659 11.97659 11.97659 11.97659 12.09066 12.31878 12.31878 12.09066 12.09066 12.09066
 
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Base table and stablized are always used in open loop as Dave mentioned. Closed loop is only one value 14.67 so there's no need to have a table for that.

Once the car gets to 180 degrees it'll switch over to the stablized table from the base fuel table at any time the car comes out of Closed loop and goes into open loop, such as flooring it, or very high loads.

Frit
 
great info guys. I was always told that base was CL and stabilized was OL.

I'm surprised that there is no way to change the ratio under CL if there is a high load situation. I assume you can reach high load without being at WOT and still in closed loop. It will always command 14.64 regardless?

So the start-up fuel table acts as a multiplier? Using the values in this table vs. ECT and time to adjust the ratio for a certain time period. Then it will command continuously 14.6 under all CL throttle inputs. It will use the base fuel table under OL until it reaches 180deg, then it will reference the stabilized table. Am I following this correctly?

Is there any reason why my base and stabilized table can't be 100% identical?
 
The are several scalers that can be set as to when the car comes out of closed loop mode and goes into open loop mode depending on load etc. You won't see those settings in SCTuner though (and alot of others). One setting that is normally lowered is the ECT temp of when the switch to stablized fuel table from base occurs. This is to fit inline with the 180 tstat.

The idea behind the base fuel table is to allow a bit more enrichment while warming up. Dave would be the better one to answer if its ok to set both of them the same

Frit
 
The switch from CL to OL occurs based on load so you will never be under severe load in closed loop as long as your tune is correct. Incorrect load scaling (for those who scale injectors) or an incorrect MAF function (for everyone regardless) can cause the car to be in closed loop beyond the OE specified load values. You can change these load values (assuming SC Tuner gives you access to the function) if you want.

Since narrow band 02's cannot accurately read any AFR's other than 14.64, they cannot be used to control any AFR other than 14.64. Furthermore, closed loop operation strategy includes the switching process during which AFR fluctuates normally from about 13.5-15.5. You would not want switching to occur under conditions that require a richer mixture.

The base table and stabilized tables cannot be set identically because they are normalized by different values (ECT and load vs. RPM and load). They are very different tables. You do not want to change very much on the base table as it is only used for warmup purposes anyway. You should not be thrashing on the motor during warmup and leaning it out will just cause initial drivability issues. If you wanted to set your high load, normal operating temp cells to match your stabilized table that would make sense but that's about all I would do. I guess you might use this if you were trying to dyno the car when ECT had not reached the switching temp yet or something like that.
 
Alright, again, excellent info guys. :) I'll try to do my best with what I've got, and things are much more clear now. In the very near future I'll have to look into getting the Pro Racer Package.
 
Once you get your membership up and running you'll find out about something even better....
 
I guess I have another question that one of you may be able to answer.

I got the car up and running after a few years in the garage. I changed the file completely and started from scratch. My idle seems great, I command 850, and I get an idle exactly at 850. I turned off the adaptive control and tuned the lower end of the MAF table and logged a few mins of data at various RPM's, and entered that data into the airflow for closed throttle. Here is my issue:

When under WOT, the ratio is lean at 12.9. I want to get it down to a 12.1. Before I just adjusted the MAF table in that area and all was good. My stabilized fuel table is commanding a 12.1 from 3000-5000 under 90-100% load. If i adjust the maf table, I don't see any change in my WOT ratio. So I'm wondering if it's using some other load value.

Before I used to tell the ECU that I was running 30lb injectors when in fact I was running 42's with the corrected sampling tube (73mm, RED).

Now that I tell the ECU I run a high slope of 42 and a low slope of 48...do I still need to run the red sampling tube? Or should I switch to a stock/clear tube? I'm under the impression that the sampling tube is forcing the ECU to reference a different load value.

I also have a part throttle/medium load miss where the car will buck slightly around 2k for 1 second, and the ratio will show a lean condition, then return to normal. Not sure if the two are tied together......
 
You have just discovered why I always scaled down the injectors up until recently when Frit was able to decode some more parameters that help us get around that. Scaling injectors is actually a totally acceptable way of extending the capabilities of the processor. It isn't commonly known, but Ford actually scaled injectors on the GT because of other hard limits in the processor. It's a completely acceptable way of doing things.

Anyway, your lean condition is being caused by an MAF clip value. As for a part throttle lean condition, have you looked at your accelerator pump values? You'll need to increase them since you are no longer scaling everything.

Last time I checked the SC Tuner did not offer you the ability to get around the scaling issue but that may have changed recently. You might just need to get an update from Spiro. But really the best thing to do would be to switch over to Binary Editor to run your EEC Tuner. The interface is better and we have a lot more parameters available to us. You'll need to contact Frit to get the necessary files for the SC, but you can purchase the software right off the Binary Editor website. www.eecanalyzer.net
 
Now that I tell the ECU I run a high slope of 42 and a low slope of 48...do I still need to run the red sampling tube? Or should I switch to a stock/clear tube? I'm under the impression that the sampling tube is forcing the ECU to reference a different load value.

You still need the red sample tube. If you tried to run a stock sample tube you would simply hit 5.0 v at about 4000rpm and fuel control would be all over at that point. By inputing the actual injector files, now you have to also put in the actual MAF function for that meter. It's really as simple as just increasing the function by a factor of 1/.714. I'm assuming you probably already did that. But this won't work until you unlock the MAF clip.
 
Before, I was able to scale things by decreasing the displacement scalar, keeping the injector values stock, and modifying the transfer function.

My accelerator table was modified, and it used to work like a charm, but again, it probably worked alright when things were scaled.

I guess I could go back to the way I was doing it before, but I always had a hard time getting the car to idle right and finding the correct airflow values at idle. When I entered the exact injector values, things worked perfectly except for that lean condition.

It seems like if you scaled some of the inputs, then the load calculations could be off.
 
Before, I was able to scale things by decreasing the displacement scalar, keeping the injector values stock, and modifying the transfer function.

My accelerator table was modified, and it used to work like a charm, but again, it probably worked alright when things were scaled.

I guess I could go back to the way I was doing it before, but I always had a hard time getting the car to idle right and finding the correct airflow values at idle. When I entered the exact injector values, things worked perfectly except for that lean condition.

It seems like if you scaled some of the inputs, then the load calculations could be off.

Well, it's a little complex to explain everything all right here in a thread but there is no reason why scaling will not work excellent. You should input all the correct injector values into a spreadsheet and then scale the slopes, breakpoint, cranking pulsewidths, and displacement by .714 and enter these values into your file. This will get everything close. Then turn closed loop off and fine tune the MAF (be sure to clear adaptive memory first!). If you have a scanner capable of watching STFT's then you can leave closed loop on but turn off adaptive. Either method works good. Once you have the MAF tuned, 99% of the rest is just a matter of matching the TB to the EEC. I have done this via the software many times but over time I have learned instead that tuning the TB and leaving the idle and dashpot values (other than idle speed) all stock is the best method. Your cam is mild enough that all the stock settings will work just fine. The TB adjustment is a very fine adjustment. Adjust the bypass screw 1/4 turn at a time until you find the right spot so that it neither dips nor hangs excessively after a 2500rpm coast down (car in neutral).
 
I'll give that another go and see what happens. I had great results when it ran a few years ago except for the idleing issue, I just thought this was a better way to do it.

Should I scale the injector offset values, or just the breakpoint? It seems like the breakpoint is set at .00004. I also have the offsetvalues for lucas injectors as well as FMS 42's. Continue to scale these values?

I'm also assuming that by turning off adaptive control that I should be able to tune the curve. Is it nessesary to force open loop by lowering the TPS value if the adaptive is already turned off?
 
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Adaptive controls your long term fuel trims but doesn't have any affect on short term. If the EEC goes closed loop it will automatically make compensation of up to 25% to maintain 14.64. You can't change that so to dial in your lower end of the MAF function you'll have to force open loop. Best way to do it is to lower "load to go open loop vs. ECT" to 0.
 
Adaptive controls your long term fuel trims but doesn't have any affect on short term. If the EEC goes closed loop it will automatically make compensation of up to 25% to maintain 14.64. You can't change that so to dial in your lower end of the MAF function you'll have to force open loop. Best way to do it is to lower "load to go open loop vs. ECT" to 0.

This software doesn't have that feature....figures....Any other way? I thought that if adaptive control was off then the ECU wouldn't reference the o2's or wouldn't make any corrections.
 
Adaptive is a learned fuel adjustment based off of the short fuel trims. The short term fuel trims are immediate on the fly adjustments to keep the AFR at 14.67, and the EEC monitors those and creates the adaptive long term fuel trims over time in an attempt to bring the short term fuel trims adjustments to zero.

Turning adaptive off means your car is only going to run on the short term fuel trims with no long term ones being applied, but the car will still run in OL and CL modes.

As Dave mentioned earlier, you might want to consider moving to different software that is alot more current with settings for the EEC. You're really limiting yourself with that old software, and consider a hardware upgrade as well. The EEC Tuner's are old hardware and was good in its day, but there is better stuff today.

Frit
 
This software doesn't have that feature....figures....Any other way? I thought that if adaptive control was off then the ECU wouldn't reference the o2's or wouldn't make any corrections.

TPS for WOT and TPS for open loop are two different scalers. Not sure if you have both available to you or if you have one, if it is properly labeled. It gets tricky and not all softwares have it right. You can test the theory by watching for active switching of the 02 sensors. You should be familiar with the typical closed loop switching signature of the 02's. If you don't see it then you know you are open loop.

Like I said, adaptive refers to long term fuel trims and doesn't affect short term. Closed loop is another way of referring to short term fuel trim. Adaptive is the ability to alter fuel cells based on the information gained from reading the short term fuel trims and this is called long term fuel trims. You can also control how the EEC learns in adaptive but that may also be outside the ability of your software.

You should really look into BE, it's that much better.
 
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