Decel / Idle Return / Tq ctrl Spark

[CCS86]

What about enabling VSS @ 128mph to rule that out..
Spark Decel Table: 1500+ rpms lower the spark to say 10-15*. Raise under 1500rpm to 20+ degrees progressively higher towards idle?

It really seems like the car thinks it should be decelerating faster so it cuts fuel because it doesn't have enough authority. These things are a pain sometimes hope you get it resolved...

I did away with torque based decel and went full dashpot. She drives like a dream now

DFCO isn't really about torque control though. It's a fuel saving measure. Any time you are above the minimum RPM, are at speed, and are off the pedal entirely, it should be going into DFCO.

[MRRPMBRP]

I messed with mine again yesterday, tried all the suggestions in this thread to get timing to not go low, after decel, going into idle, no help at all.
I went to torque table, (GT500 here, so only one torque table) raised torque 50%, calculated inverse, made it worse. So I went back to previous settings, then lowered torque 50%, and again calculated inverse, worked great, no low timing now.

I still am not sure how torque is used, seems like adding torque would keep the motor alive and add timing & open throttle, when the opposite is true. If I have throttle hang, lowering torque (and calculating inverse) is the solution, if I have throttle shutting, lowering torque is the solution. Seems like about any time I need to change torque values, they need to be lowered. Maybe since this car has a really large MAF tube, the torque values are all messed up, since way more air is going in than is known, so for calculations to be correct.

[CCS86]

I have seen similar, at least on the return to idle:

When it is using torque control, the inverse table gives it an estimated desired load, which gets converted into desired MAF, then desired ETC angle. If all that is too high, it will reduce spark to keep RPMs down. So lowering values in the inverse table will tend to give you a lower ETC opening, and higher spark.

My problem is that on the Coyotes, once it settles into an idle, the mode changes and any improvements from this method disappear. It sure feels like I am missing table(s).

[CCS86]

Here is my current state of affairs. Much better than when I started the thread:

Slow reverse sweep.jpg

This is with the return to idle speed set super slow. You can see the idle spark make a drastic change one settled into the idle.

Right at this point, the spark source changes from "torque control" to "idle feedback", and torque source from "target N" to "driver demand".

At this point, the PCM adds ETC angle and takes away spark to maintain the same RPM.

You can also see that over time it is slowly adding more ETC angle, and less spark.

I tested:

• TQ Inverse values
• TQ values
• Idle Control Enable RPM Error
• Spark Only Torque Ratio for idle control and driver demand
• Spark Torque Ratio Limit for idle control and driver demand
• Driver demand torque
• ETC Idle Throttle Angle Expected vs. Airmass
• Idle Airflow (Drive) vs. Desired Idle RPM
• Spark idle minimum

None of these had any impact on idle spark advance in "idle feedback" mode. I realize that the PCM uses PID control to maintain idle RPM. I have designed and tuned a number of PID controllers myself. Those PID settings are only controlling how spark correction reacts to changes in RPM though. The PID controller does not govern what would be considered the spark "baseline".

[MRRPMBRP]

Here is my current state of affairs. Much better than when I started the thread:

Slow reverse sweep.jpg

This is with the return to idle speed set super slow. You can see the idle spark make a drastic change one settled into the idle.

Right at this point, the spark source changes from "torque control" to "idle feedback", and torque source from "target N" to "driver demand".

At this point, the PCM adds ETC angle and takes away spark to maintain the same RPM.

You can also see that over time it is slowly adding more ETC angle, and less spark.

I tested:

• TQ Inverse values
• TQ values
• Idle Control Enable RPM Error
• Spark Only Torque Ratio for idle control and driver demand
• Spark Torque Ratio Limit for idle control and driver demand
• Driver demand torque
• ETC Idle Throttle Angle Expected vs. Airmass
• Idle Airflow (Drive) vs. Desired Idle RPM
• Spark idle minimum

None of these had any impact on idle spark advance in "idle feedback" mode. I realize that the PCM uses PID control to maintain idle RPM. I have designed and tuned a number of PID controllers myself. Those PID settings are only controlling how spark correction reacts to changes in RPM though. The PID controller does not govern what would be considered the spark "baseline".

I'm pretty sure, from messing with mine over the past few days, idle spark is baselined by idle spark settings, but only when idle mode. I have all mine set to 15degrees for simplicity at the moment, I may change them later. The spark idle minimum (44582) is spark minimum setting when idle mode is controlling spark. A setting, in my case, 15degrees, will not allow any spark adjustments to control idle, since spark is set to 15degrees and it can't go below 15degrees. If I set spark minimum to say -5, spark can range from the 15 spark setting, to -5 to control spark during idle, which is how I have mine set at the moment. I did have some idle rpm flare when going into idle mode, but lowering this setting helped a lot.

[CCS86]

Those settings appear to have absolutely no effect on my car.

Here's where I am set, yet still get spark from 6* - 10* once truly idling:


Spark tables.jpg

[MRRPMBRP]

Why have you screenshotted your cylinder pressure limit table?
Doubt you'd ever get to those limits, at idle.
Do you have spark idle minimum, 44582?

[CCS86]

Why have you screenshotted your cylinder pressure limit table?
Doubt you'd ever get to those limits, at idle.
Do you have spark idle minimum, 44582?

I showed that because someone else had mentioned where those values were set low in the idle range and capping advance.

Look at my photo again. Spark Idle Min is in there and set to 20*. Doesn't seem to have an effect.

[MRRPMBRP]

Ok, on mine, spark idle min, and all the other idle settings are only applicable in idle mode.
Your spark should be steady, or almost steady in idle mode, since the lowest you have is 21, and minimum is 20.
Is spark in idle mode, and timing still low?

[CCS86]

Ok, on mine, spark idle min, and all the other idle settings are only applicable in idle mode.
Your spark should be steady, or almost steady in idle mode, since the lowest you have is 21, and minimum is 20.
Is spark in idle mode, and timing still low?

I'm curious what all your modes show at idle.

Right at this point where I lose most of my spark advance, the spark source changes from "torque control" to "idle feedback", and torque source from "target N" to "driver demand".

[MRRPMBRP]

I'm curious what all your modes show at idle.

Right at this point where I lose most of my spark advance, the spark source changes from "torque control" to "idle feedback", and torque source from "target N" to "driver demand".

That's exactly what mine does, and I think this is how it's supposed to do, except for the spark retarding part.

[blackbolt22]

When I had Torque based decel enabled I saw:

Spark source = Torque Control or Closed Thr. Decel.
Torque source = Target N or Tipout Limit or Tq. Based Decel

After 5 seconds of Idle Spark source = Idle Feedback / Torque source = Driver Demand
The below settings are for "Idle Feedback" mode only:
IdleSpark.JPG

When it's transitioning between all of these modes, different spark tables are being used. It's annoying.......

I turned off Torque based Decel so now I have more control over spark during Decel due to Target N rarely being used except when car is moving & between idle rpm and 1000rpms. Before it was always transitioning to and fro in and out of Target N causing annoying surges over 1000rpms.

My engine is stock down to the paper air filter.. All I have are axle backs and a 4C Converter. Putting in the converter caused ALL of my decel troubles, even on the 100% stock tune!!

[CCS86]

Okay, I made a big breakthrough on restoring idle spark.

Not 100% sure which setting it was, since I was making batch changes, and not sure I will spend the time to fully isolate it... but I'll give some guidance:

I made some changes to the spark control gains, cold retard tables, cylinder pressure limit, RPM/Load modifier, and cranking spark; But given the operating ranges of those changes I made, I really think it has to be the first two listed.

Here are the two changes I suspect the most. Especially 32369

spark fix.jpg

[MRRPMBRP]

Mine idles good as far as spark, but GT500 tune, they were set to one stock, I haven't touched them.

32369.jpg