All Kinds of Limits

[wristshot]

Well I?ve been tinkering with this for a while now on a 2015 2.7L F150. Thought maybe it?s time to ask for some help.

I have ?Comb. Stab. Limit? and ?Turbo FMEM? limits under the Driver Demand Limit Source AND ?5 Popcorn? and ?2 Turbo FMEM? under the Torque Airlimit Source.
Even with the latest verson of HPTuners, I still cannot figure out how to prevent/raise the Combustion Stability Limit and/or Popcorn. I have raised, maxed, lowered all of the Combustion Stability and Load Limiting parameters, and still cannot get past these limits.

Are you guys (i.e. tuners) exceeding the parameter range allowed in the editor to get past some limits? For example the Max MAP before Combustion Stability Limiting is 65 inHg for my strategy. If this is absolute (?), when the boost is approx. 17 psi, limiting will be used. I?m not sure if the firmware/OS will accept a parameter above/below the max/min specified in the editor, without some strange result.

Can anyone help with how the Combustion Stability and Popcorn Limiting works? Knowing how it works and what actions the PCM take when these limits are reached/exceeded would be helpful.

The Turbo FMEM Limit is new to me (my latest tune) and I haven?t gone hunting to attempt to find the cause. I?m thinking the turbo protection parameters, are at the root this. I probably will not change these too much cause in an effort to have turbo longevity.

My performance is much improved over stock, even with these limits occurring. Ford really did a good job to be able to deal with them and maintain excellent performance.

Any help/ideas will be much appreciated. See attached log file.

2015 2.7L F150 Partial.hpl

[Trent_Petersen]

I'm running up against combustion stability <5K RPM's and Turbo FMEM over 5K RPM's and cant seem to figure out anything to get past it. I've seen reference to some table other calibrations have that I seem to be missing and am wondering if I need to ask for some more tables.

[Stevo]

I'm running up against combustion stability <5K RPM's and Turbo FMEM over 5K RPM's and cant seem to figure out anything to get past it. I've seen reference to some table other calibrations have that I seem to be missing and am wondering if I need to ask for some more tables.

Same here: on a 2016 Mustang Australian vehicle.

[Evolution Stu]

Turbo FMEM limit is usually the compressor flow limit Vs air temperature table.
Do you guys have that available in your cal?

[Trent_Petersen]

Turbo FMEM limit is usually the compressor flow limit Vs air temperature table.
Do you guys have that available in your cal?

Is that [ECM] 550011 - Turbo Pressure Ratio vs. Turbo Flow vs. Turbo Air Temp ?

I raised the values in that table, which did net me higher boost, but then I started getting the Turbo FMEM limit.

[Evolution Stu]

Is that [ECM] 550011 - Turbo Pressure Ratio vs. Turbo Flow vs. Turbo Air Temp ?

I raised the values in that table, which did net me higher boost, but then I started getting the Turbo FMEM limit.

I'm in a cafe right now having lunch so can't check but, yeah, that sounds to be right. It's an airflow table in LB/H which I have seen trigger TURBO FMEM when you hit it. I logged current airflow and then found that I was right on the money at that airtemp and moving them up 15% remove dthat limit. The only other table I recall giving me that limit was the maximum compressor ratio table on some cals.

[Evolution Stu]

I assume you have scanned for codes too?
FMEM is activated in an under / over post condition too of course.

[Trent_Petersen]

Are you guys (i.e. tuners) exceeding the parameter range allowed in the editor to get past some limits? For example the Max MAP before Combustion Stability Limiting is 65 inHg for my strategy. If this is absolute (?), when the boost is approx. 17 psi, limiting will be used. I?m not sure if the firmware/OS will accept a parameter above/below the max/min specified in the editor, without some strange result.

Can anyone help with how the Combustion Stability and Popcorn Limiting works? Knowing how it works and what actions the PCM take when these limits are reached/exceeded would be helpful.

Do you have [EMC] 4217 - Combustion Stability Min Brake Torque vs. Engine Speed available in your OS? I have seen several threads now that point to raising those as a way to help or eliminate the combustion stability limiter. I don't have it in my calibration so I can not personally verify this.

I'm in a cafe right now having lunch so can't check but, yeah, that sounds to be right. It's an airflow table in LB/H which I have seen trigger TURBO FMEM when you hit it. I logged current airflow and then found that I was right on the money at that airtemp and moving them up 15% remove dthat limit. The only other table I recall giving me that limit was the maximum compressor ratio table on some cals.

I only have the pressure ratio table, so I may need to ask to have the airflow table added. It looks like that table is [ECM] 3630 - Turbo Airflow vs. Engine speed vs. Turbo ACT

[wristshot]

Do you have [EMC] 4217 - Combustion Stability Min Brake Torque vs. Engine Speed available in your OS? I have seen several threads now that point to raising those as a way to help or eliminate the combustion stability limiter. I don't have it in my calibration so I can not personally verify this.



I only have the pressure ratio table, so I may need to ask to have the airflow table added. It looks like that table is [ECM] 3630 - Turbo Airflow vs. Engine speed vs. Turbo ACT

Table 4217 was introduced, for my OS, in a recent VCM Suite update, though I still have not been able to get around the Comb. Stab. Limit. I really don't get the parameters offered. According to the status bar help, table 4217 is the min. TQ before Comb Stab Limiting, yet scalar 50295 is the max. TQ before Comb Stab Limiting. Why have a minimum then a maximum?

2016.10.11_01.jpg

2016.10.11_02.jpg

Anyway, according to my log/s Comb Stab Limiting comes into play before these min/max TQ levels and max MAP are met.

2016.10.11_03.jpg

I still have the Popcorn Limit, maybe I have to get it worked out before the Comb Stab can be addressed.

I really wish someone could explain what causes these limits (i.e. Comb Stability & Popcorn in particular) and what control actions are taken when they are reached. I hate to work on eliminating them, not knowing why they are there in the first place.

FYI, as of now I think my Turbo FMEM limit was a result of underboost. I have got my TIP error lower and the Turbo FMEM Limit I was experiencing has gone away - for now.

[Bugasu]

You guys are somewhat in the wrong area, but pretty close.
First off, when Torque Airlimit Source becomes Popcorn, DD Limit will always be Combustion Stability Limit. In this case, its not the Combustion Stability Limit you guys were discussing though, but the cold combustion stability limit.
If the CSL you guys were showing was active, your Torque Source (not Torque Airlimit or DD Limit) would be Combustion Stability Limit.

Popcorn is named after the sound that late combustion / misfires that dump fuel into the exhaust make (like you're popping popcorn in the exhaust).
There are two negative effects to this: 1) Fuel in the exhaust drastically increases hydrocarbon emissions. 2) An unstable/misfiring engine is pretty noticeable and sucks.

The ECU does two things to combat this:
1) As many are aware, cold combustion requires more fuel as some of it is lost. Cold engines aren't as efficient at combustion, and fuel itself may not vaporize or burn quite as well.
2) The ECU limits load in this scenario to help guarantee they can reach stable combustion.

What you're seeing is #2. For the most part, this limit is sometimes cal'd out of range of the stock tune once warmed up, but once you raise boost, suddenly you run into it despite not truly being cold anymore. Depending on the ECU generation you have, its either a Load or a MAP limit. Located here:


Now, on turbocharged applications like all Ecoboost, the LSPI limits right to the left of there also show up as the same Popcorn limit. Why? I dunno, ask Ford. So make sure those are also out of range (though be careful at true low speed. Those limits are designed to prevent LSPI at those lower RPMs from ruining your engine and your day).

As to Turbo FMEM, there are two scenarios. One you guys have figured out already is Overboost/Underboost. During that scenario however, WGDC is forced to 0, and the log doesn't show that, so we know its scenario #2. Scenario #2 is you're breaching the wastegate/turbo airflow limit. Again, depending on generation, its either 3D or scalar.
Older is scalar:

Newer is 3D:


Hopefully with those adjusted, you guys should be clear of your limits.

[Trent_Petersen]

You guys are somewhat in the wrong area, but pretty close.

-- SNIP HUGE QUOTE --

Hopefully with those adjusted, you guys should be clear of your limits.

Absolutely great, this is awesome!! Thanks for taking the time to explain this and post up the screenshots!

[wristshot]

You guys are somewhat in the wrong area, but pretty close.

...

Hopefully with those adjusted, you guys should be clear of your limits.

Bugasu; thank you so much for taking time and sharing your knowledge to help us. I always learn so much from your posts.
I can not wait to upload tune iteration number xxx and log away.

[reubone]

if by chance you still hit the turbo fmem after these two limiters have been moved significantly up, could it be coming from somewhere else?

[Bugasu]

if by chance you still hit the turbo fmem after these two limiters have been moved significantly up, could it be coming from somewhere else?

Overboost could come into play as well. If you exceed the limits there it'll kick you into Turbo FMEM until you restart the vehicle. If the code sets, you'll permanently be in Turbo FMEM.

[reubone]

have you ever come across an scenario where your over boost drop down menu option was set to disable and you still got an over boost detected yes crap. this enables my turbo fmem anything over 22 lbs. really anything over 21 lbs. i dunno gonna have to try it again

[Lidio Iacobelli]

Hey guys,

This is one of the first times I've posted here. I've been using HP-tuners with GM's for nearly 10 years, and Hemi stuff for about 1/2 a year or so. My personal 2.7L Eco-boost f-150 is the very first time I've worked with HP tuners on a Ford product. I wanted to share with you 2.7L eco-boost guys what I've come up with on my personal 2016 f-150 with the little eco-boost motor. Thought this might be a good thread to get involved in.

First off, I've never been a big fan of Eco-boost (I know, here it comes!), me and my shop did some EcoBoost tuning when they first came out back in 2009 and then I got out of it by 2012, my shop was just too busy with plenty of Mustang and GM v8 cars and trucks that I just didn't wanna make time and resources for EcoBoost any longer. Plus SCT was the only game in town for me at that time, and it was difficult to figure things out to say the least. I?ll admit, I don?t and didn't know it all at the time. As a small independent Ford performance shop, plus SCT didn't have value files at that time in the early stages of EcoBoost tuning. Plus the ridiculous SCT Flash times made it difficult to develop what I thought was good and well thought out tunes for EcoBoost at the time. So I stayed away from it all together for several years till recently (I know, lots of business opportunity with EcoBoost I get it).

My shop doesn't do mail order or anything like that. 100% of my business is all local, so I have no problem sharing what I've come up with. Not saying its anything great, but I've spent about the last four weeks on my 2.7L truck using HP-tuner stuff. It?s been a work in progress -- I've messed with it every time I drive it, even just to run errands, or pick up milk!

I wanna also make it clear that this is a truck (obviously), not a toy or a car, and I will be towing with it about two to three times a month. The trailer with a car is about 6000lbs to 6500lbs total. So I wanted to make sure that I didn't do anything that could lead to a failure or problems while towing and subjecting it to major loads for extended periods of time. Like up a long high grade and etc? Which I will be doing with a trailer behind it often? Not having it burn down was the most important thing. Other than an older power stroke diesel, I've never owned a light truck with a gas engine and Turbo's. So I wanted to very carefully make a tune that would make nice gains all around, take advantage of 93 octane, but not cook anything to much during extended medium to high loads with a trailer behind it up a mountain in PA or where ever.

Before I did any tuning, I watched and did a lot of data logging with it while still stock, with and without the trailer behind it. And I have to say it towed very well while it was all stock?. Much better than my recently sold 5.4L 3v truck with only a 4-speed auto.

So I wanted to come up with a tune that would increase performance all around and take advantage of 93 octane as I said. And not deviate to far from certain stock parameters to protect mostly the Turbo?s and cat?s.

All I did at first was basically use HP tuner to just turn off as much of the transmission TQ limiters and input limiters and etc as I could, without harming any of the gear "Shifting TQ reductions". I like to keep that stuff on and work with it rather than just go in there and click it all off. As soon as I disabled all trans limiters, but successfully kept the shifting TQ reductions working. The ECU immediately started commanding well over 400lbs of TQ as opposed to always keeping it just under about 380lbs or so. I also discovered that the stock tune did not always allow the VCT to go into ?optimal power? when I demanded full power. This may or may not be a big deal to some tuners, but I changed that around and got it to go into "VCT optimal power" on the cams anytime the pedal is nearly floored, and over about 1800 RPMs.. Seat of the pants seemed better this way to me.

From there I backed off or delayed when it went into cat protection. Some may argue this is a bad move since I will be towing with it, No argument there. Stock it would go into cat protection within about 4-5 seconds of wot, and about 3-4 seconds with a trailer behind it. I've moved it up a bit by tweaking the inferred exhaust temp table only from about 2000rpms and up and only from about 120% load and up. Just didn?t wanna see a lambda of about .7'ish while racing the Hemi trucks around town!
Once I started to raise or turn off all the tans TQ stuff and etc? I then ran into all kinds of other limiters and etc on this one as well. I've seen the; Turbo FMEM, running out of fuel, combustion limit, exhaust temp control, and cat protection. Never seen the popcorn one though?

My target boost for all around was going for about 18-19psi. Stock was rarely over 14-15psi and average was usually about 10-13psi. And sometimes it was all over the place for some reason, but never more than about 14-15 typically. For the most part the beautiful thing about the 2.7L is the load and most of the maps are set up stock for about 18-20psi of boost, so once you move some limiters out of the way, you really don?t have to do much with spark and A/F at wot, it?s already there in my opining.

Even while all the various limiters and etc were popping up on me, The A/F fuel pretty much stayed at the commanded WOT Lambda and the timing seemed to stay where it should too.

I've got most of the TQ source limiters to go away on my tune. But I've learned to ignore the combustion limit for now. No matter what I've done in HP-tuners, it won?t go away. All the other stuff that used to pop up are gone for me and it runs great, carries about 18-19psi from 2500rpm on up with a hard brake boost in 4x4. No more over boost condition or anything. At WOT both the A/F and the timing do as they should even while the "combustion limit" is showing. So I gave up on it and decided to just let it go for now. I think we're missing some stuff in order to find or correct this combustion limit thing?
On my DynoJet when it had 87 octane it made 260ish RWHP in manual 3rd gear, with tuning and 93 octane it is now 325 to 330rwhp! pretty damn good I think. I think there is more in it still.

Reason I decided to post here and share all this is frankly I wanna see what others may think of what I've come up with. Plus I have a couple of concerns that I can't seem to figure out. This thing does some horrific spark reduction during tip-in off idle. I can't stand that shit more than anything,, to watch the timing go very negative during a rapid throttle snap just eats me up! you can actually feel it too!
My 2.7L will go as much as -17* or more if you smack the throttle quickly off idle.
I've tried everything you can imagine that we have access to in the HP tuner stuff. The only thing that helped it, but didn't fix it entirely is; I went into each borderline table and added as much as 4-12* timing under 100% load, and under about 1200rpm. And it helped a little, but it?s not cured by any means. I've disabled the knock sensor under 1200rpms, and anything I could experiment with, and nothing completely cured it. The tip-in spark tables seemed to do nothing at all to fix this. Something is missing I believe. I can usually get rid of it on other Fords with SCT, and GM's with HP-tuners. Maybe some settings don't work till I do a "Full write"? Haven't tried that yet.

Also, this file that I'm sharing has the Trans shift schedule, convertor lock-up, and etc extensively modified to suit my liking, and what I've learned over the years my local customers tend to agree with. It could still use some refining.
Another problem there is; I prefer to command sooner "coasting downshifts" as the vehicle comes to a stop or slows down. And since I command a 2-1 downshift a little sooner than stock, I think I'm feeling the coasting clutch disengage just before the truck comes to a complete stop at about 2-3mph. Not sure, but it feels like it's un-binding or something (doesn't do it all the time). I believe these have a coast clutch in the 6R80 Trans that we have no access too in the tuning; I think it applies at very low speeds and then comes off when nearly stopped, or something like that. I swear I've felt it do this with the stock tune in it too.
Not sure. And occasionally the rev matching causes the truck to surge a tiny bit during the 2-1 coasting downshift. It?ll do it only two or three time a day after lots of miles of driving, and not at all sometimes? Seems to happen the most if you have a little bit of input on the steering wheel as its slowing down, like about to pull into a parking spot.

I also want to mention that Metroplex was a big help with my 2.7L ecoboost tuning effort too. Turns out he was local to me here in Michigan and we have actually met, and have since been trading lots of info on all this stuff.
I'm open to any criticism or help on this as long as maybe one of you tuners actually and possibly tries it in the real world. Some of its hacked possibly, and some if it I may have experimented with it, and it if had no relatively immediate effect, I let those settings go sometimes where I may have left off after determining they didn't seem to work.

For me this tune drives great so far, and only real major problem I'm chasing is it will not allow Full boost (may be a good thing) in 1st and only 1st gear when hitting it hard from a dead stop or a very low roll, (not a brake boost, just smack it off idle) like under 10-15mph? it is clearly doing some sort of TQ control, or TQ reduction, or Power-train protection that I can't find.
The throttle body will intentionally not fully open in only in first gear at very low MPH,,, any other manual gear when selected or held at a very low MPH or dead stop will allow it to achieve full boost or the max boost almost instantly, but not in 1st. Its in the tune somewhere, because it'll open the TB completely and let it build more boost earlier in other gears when at slow speeds and low RPMs. This is another area where I'd like to see if you guys have some input? I've also attached a log of various WOT shots in 1st gear and then manual 2nd and gear (I've logged the commanded gear so you can see when and where I did it), and the log clearly reveals the ECU opening the TB far more at low RPMs in manual 2nd then 1st.

Thank you guys

[reubone]

Screenshot (60).png

maybe switch to 0?

[Lidio Iacobelli]

Thanks for responding,,,, But that switch doesn't work at all... I think the tip-in logic can sometimes refer to managing bobbling more associated with manual trans equipped vehicles. Either way it was one of the first things I tried on mine. No difference what so ever with tip-in spark retard.

I never understood why so many OEM cals do such big spark reduction off idle (especially the last few years).. The hemi cal's stock are much more aggressive (in a good way) then Ford and GM's when snapping them off idle.
I've watched some recent scat-pack and Hellcat spark from the factory, and they do not do nearly as aggressive of tip-in spark reduction as some of the Fords and GMs will do... Amazing how a hellcat will snap off idle when bliping the throttle. doesn't even come close to going negative on the timing on the Hemi stuff, and just Buzzes off idle quick and responsively!

I'm sure its an emissions related thing or something like that... An actual Ford calibrator I knew back about 10-12 years ago once told me that under no circumstances can a consumer ever here a Ford ping no matter what the conditions are, or poor octane and etc.. back when they didn't have as good as Knock sensors like they have now days.

The modern LT-1 motors are the worst I've ever seen with tip-in spark reduction, at least local to me.. those newer Di Vetts will actually flat out stumble and response like complete crap off idle... cant believe consumers and car critics, and all the various media who have reviewed those cars have never mentioned it, (that I'm aware of).

One of the ways on other Fords that I've aided the tip in spark reduction (with SCT) is to make use of the minimum spark scaler. (I've requested for HP tuner to add it along with the max spark clip too).

You cant make the minimum to much higher if you want to make sure TCS, and trans TQ reductions to continue to work correctly. stock on most Ford the minim clip is at about -20. I've set it at -5 and it'll help the tip-in stuff with out killing the TCS and other requirements.

I flashed my 2.7L back to stock to make sure I wasn't making it worse as I progressed with tuning it (and to make sure I wasn't going crazy), and its really bad stock,,, so much that if you very quickly snap it,,, it has a physically noticeable stumble off idle in "D"

[murfie]

For your spark raise your low load maximum. I think metroplex found this out when comparing an 3.5l F150 tune to his. looks like the 2.7l has an aggressive table as well.

The 6r80 applies element D and A in first gear below 3 mph above it's just A and the one way clutch. D overrides the one way clutch by holding the rear planetary gearset stationary. When D is not applied the one way clutch holds it one way and allows freewheel the other eliminating engine braking. So you are feeling D being released while the OWC is applied. Happens when turning sharp at low speed as the rear differential allows the outside tire to spin faster and basically causes the output shaft to speed up faster than the 3 mph threshold. This would be considered an upshift of 1-1. Your goal would be to delay the D offgoing a little on this shift. A small Increase in starting pressure or boost pressure should do this.

The problem with boost in first gear, I think its because the actual TIP exceeds the expected TIP table. In first the turbo inferred turbo speed rises much faster. Below is two pictures comparing the 1st and 2nd path through this table. I have the scroll where the TB limits each gear.

First gear TIP.PNG

2nd TIP.PNG

[Lidio Iacobelli]

For your spark raise your low load maximum. I think metroplex found this out when comparing an 3.5l F150 tune to his. looks like the 2.7l has an aggressive table as well.

The 6r80 applies element D and A in first gear below 3 mph above it's just A and the one way clutch. D overrides the one way clutch by holding the rear planetary gearset stationary. When D is not applied the one way clutch holds it one way and allows freewheel the other eliminating engine braking. So you are feeling D being released while the OWC is applied. Happens when turning sharp at low speed as the rear differential allows the outside tire to spin faster and basically causes the output shaft to speed up faster than the 3 mph threshold. This would be considered an upshift of 1-1. Your goal would be to delay the D offgoing a little on this shift. A small Increase in starting pressure or boost pressure should do this.

The problem with boost in first gear, I think its because the actual TIP exceeds the expected TIP table. In first the turbo inferred turbo speed rises much faster. Below is two pictures comparing the 1st and 2nd path through this table. I have the scroll where the TB limits each gear.

First gear TIP.PNG

2nd TIP.PNG

I'll experiment with some of these in the next day or so and report back.

On the issue of lower boost in 1st gear,, should i then mess with the expected TIP Table? I've already raised it a bit across the board and then much more on the far right columns. and/or try something else?