Why can't I achieve full fueling at higher RPM?

Anybody have some advice for me as to why I am unable to hold my commanded fuel? I was starting to think there must be a limiter parameter/table that was not accessible in the VCM Editor for my OS, but upon submitting a ticket to Support @ HPTuners, they assure me that it is a tuning issue, but didn't give any hints as to what I'm missing.

I am commanding as much as 185 mm3 from my pedal table and pulling a bit past 4k RPM, but I notice I am never achieving that fuel rate, and am consistently dropping mm3 throughout nearly the entire RPM range.

I am including a log file. Any help would be greatly appreciated. Thanks!

Attachment 64710

The response you got from HPT is indeed correct. It is not a software issue.

Your data log shows what is controlling the drop in mm3.

Why are you trying to command much more than 140mm3? The HSG tops out at 160mm3 and the pulse and fuel pressure tables aren't scaled any higher than 140mm3.

Doesnt the pressure map scale need to be mapped out to the higher 185mm3 value? Or is the last table row entry carried out to higher axis values?

to me it looks like the all speed gov is under control...

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Originally Posted by Moparmatty

The response you got from HPT is indeed correct. It is not a software issue.

Your data log shows what is controlling the drop in mm3.

Why are you trying to command much more than 140mm3? The HSG tops out at 160mm3 and the pulse and fuel pressure tables aren't scaled any higher than 140mm3.

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It seems to be a sort of common theme to command more fuel than you can possibly run so that when the limiters and governors try to stomp on it, you still get full fuel for longer than you would have.

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Originally Posted by steve05ram360

Doesnt the pressure map scale need to be mapped out to the higher 185mm3 value? Or is the last table row entry carried out to higher axis values?

to me it looks like the all speed gov is under control...

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If you exceed the scale of any table, it maintains the value of the last row/column, correct.

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Originally Posted by steve05ram360

Doesnt the pressure map scale need to be mapped out to the higher 185mm3 value? Or is the last table row entry carried out to higher axis values?

to me it looks like the all speed gov is under control...

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Why go to the trouble of rescaling past the 140mm3 though?

I've tried it both ways, commanding up to 140, and 185. I am well aware I won't get anymore fueling beyond the last defined mm3 column, but it was a last ditch effort to command more than maximum to see if it would help.

Moparmatty, do you have a suggestion as to what I should be looking into?

Am I missing something in a table, or is it a single parameter?

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Originally Posted by B00STJUNKY

I've tried it both ways, commanding up to 140, and 185. I am well aware I won't get anymore fueling beyond the last defined mm3 column, but it was a last ditch effort to command more than Max to see if it would help.

Moparmatty, do you have a suggestion as to what I should be looking into?

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What does your log tell you the cause of the mm3 drop is?

All speed (normal) is what is limiting fuel.

I see some droop parameters and have tried zeroing those out. That was a bad result (runaway condition).

I've zero'd out some of the Fuel Decrement, just not the threshold parameters.

I've been eyeballing the Deceleration parameters, but keep telling myself those must surely be for when you are decelerating (ie. no throttle), so I've not tried messing with those yet.

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Originally Posted by Turbo_Mike

If you exceed the scale of any table, it maintains the value of the last row/column, correct.

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Thanks...

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Originally Posted by Moparmatty

Why go to the trouble of rescaling past the 140mm3 though?

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I was not sure if the last row was maintained or not, hadn't figured that out yet. Rescaling allows for finer control if needed. I did this on 2 maybe 3 tables so far, the one that comes to mind is the pedal map. Tweeked it to match my goals and driving style. Another one is the baro correction, I had no idea the small fluctuations in pressure changes performance the way it does.

PM sent.

Go to engine, fuel, all speed gov is at the bottom. Bring it up to 7000 on all 3. You may have to bring it up higher, it should start pulling fuel way higher than before. The description says to set it to desired max rpm.. but I don't buy into that. It's a pid limiter that will pull fuel until you reach that rpm, just set it way above. You should then have full fuel to what ever you set you cut out at. I like to use the other limiters to pull fuel, such as the boost limited fuel table, and the throttle tables.

Also, you're going to need a lot more timing up top in order to make any power in the higher rpm.

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Originally Posted by Dom_c13b

Go to engine, fuel, all speed gov is at the bottom. Bring it up to 7000 on all 3. You may have to bring it up higher, it should start pulling fuel way higher than before. The description says to set it to desired max rpm.. but I don't buy into that. It's a pid limiter that will pull fuel until you reach that rpm, just set it way above. You should then have full fuel to what ever you set you cut out at. I like to use the other limiters to pull fuel, such as the boost limited fuel table, and the throttle tables.

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Thank you. I had one other individual from this forum PM me with similar info. You guys are awesome. I much appreciate it.

Those RPM limit descriptions are VERY misleading. Not only in saying to set them to your desired cutoff point, but also in stating that they are specific to manual transmission calibrations. My truck is an automatic, so I hadn't put much thought into them.

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Originally Posted by Dom_c13b

Also, you're going to need a lot more timing up top in order to make any power in the higher rpm.

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Wow, I thought I was already getting close to the limits of how far I could advance my timing. I've always heard no more than 32* advance as a general rule of thumb.

Do you have another take on that?

Again, thank you very much for the advice, fellas. I'll give this a try as soon as the bad weather breaks.

32 is a good number to use for a stock truck, stockish rpm. When I get a chance to get back on my laptop I'll check to get exact numbers, but on my 5k rpm tunes I'm up in the 40+ range. At 4k I'm usually around 38+ depending on duration obviously. I also shut injection off at 23* atdc.. after that it just seems to make heat and smoke. May be able to get away with more on a stockish truck turning lower rpm but with big injectors turning high rpm that's a good stopping point.

Great info, thank you for sharing :cheers:

From looking at your log, more then likely that All Speed Gov. B is the main one that is doing your limiting. On my truck setting it less the 5500, will pull fuel away. I normally have it set to 8000.

Paul

SOI in the late 30's early 40's wouldn't apply to 143* injectors though would it?

Dom, Paul, and Johnny, thank you very, VERY much for your contribution. You three have already provided more helpful insight and information in a mere 3 or so posts than this entire diesel forum has provided in the last year or so.

Kind of frustrating to have guys tell you that your issue lies within your tune and somewhat lead you on as if they might be helpful, only to leave you hanging when the answer was seemingly right at their fingertips.

I've been chasing full fueling up past 3200 RPM for the better part of a year, and the only other person who has been helpful in the journey to getting there has been Les from Silver Bullet, who ironically tunes diesels for a living, and would thus have the most to lose by sharing knowledge.

Again, thank you guys very much. Now, it would be nice and helpful for others who take on their own projects if HP Tuners would update their definitions for the AllSpeed RPM limits so that they aren't so misleading.

I went through the same thing when I started tuning 3-4 years ago with Efi-Live. It was very much the same, I'd read til my eyes bled and couldn't figure out the full fueling over 2900rpm. I'd get to a point in a post where the person would figure it out and then it was crickets' no one would point to where it was. I finally figured it out a couple years ago while just trying something on my truck and it worked.
I'm a hobbiest tuner, I've tuned a handful of local trucks and my trucks for a while now with great sucess. I was always so frusterated trying to figure stuff out that I said I'd do my best to help others when I could. That being said, I still flash my truck 5+ times a week probably. Always trying new stuff.
There were a few efi-live guys that were very helpful in the begininng and Les was one of them, he's given a lot to the diesel tuning community.

Muz79, I haven't brought a 143 truck over 3600rpm yet due to none of the ones I've tuned have the hard parts to do it. At 5000rpm you're window of time to inject the fuel is very short, the only way to get the fuel in there is with more timing. Sure there is a point that it's too much, I personally haven't had to opportunity to find that point with an early truck yet. The later trucks, I'm up close to a 60% timing split in the 3500rpm+ range. I've had my truck on the dyno testing just timing changes and seemed to keep gaining power until then. Didn't really feel comfortable going much further.
Given the opportunity I would not be scared to bring an early truck to 5krpm and 40* timing. At 2000rpm I'm in the 10-12* range..

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Originally Posted by B00STJUNKY

Dom, Paul, and Johnny, thank you very, VERY much for your contribution. You three have already provided more helpful insight and information in a mere 3 or so posts than this entire diesel forum has provided in the last year or so.

Kind of frustrating to have guys tell you that your issue lies within your tune and somewhat lead you on as if they might be helpful, only to leave you hanging when the answer was seemingly right at their fingertips.

I've been chasing full fueling up past 3200 RPM for the better part of a year, and the only other person who has been helpful in the journey to getting there has been Les from Silver Bullet, who ironically tunes diesels for a living, and would thus have the most to lose by sharing knowledge.

Again, thank you guys very much. Now, it would be nice and helpful for others who take on their own projects if HP Tuners would update their definitions for the AllSpeed RPM limits so that they aren't so misleading.

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What is it with this sense of entitlement that everyone has nowadays?

Why does it seem like you all feel that you should be just spoon fed the answers to things? Then you get all huffy when you don't get direct answers.

Why should those of us that have spent countless hours of time figuring out all this stuff, just give up all of our hard earned secrets and tricks for free?

If others are willing to give up their tricks of the trade, that's their prerogative. But forgive me if I think they are crazy.

Just think about something for a minute. Think very hard. When was the last time you saw anyone who's anyone or anyone who actually truly knows anything in the Cummins tuning world make post in here?

I pointed out near the start of this thread that your datalog showed you exactly what has been causing your issue. You just hadn't figured out how to get around the issue. Sure I could have just told you exactly what to change in your tune. But what would you actually learn from that? But because I didn't makes me the bad guy?

It does suck you've been fighting this "issue" for so long. But I find it highly entertaining that one of the people that you just praised so highly, obviously didn't just GIVE you all the answers you sought over curing this "issue" in particular. So why aren't you mad and huffy at him too?

Just remember the next time any of you get pissy because you aren't GIVEN the answer you're looking for. Without a select few us, none of you would even have what you have to tune these trucks. Up until now, of those select few, I was the only one left that does post the odd time in here. You've all successfully ran off anyone that did or may have posted any useful information with your entitlement attitudes and lack of beliefs in the info that anyone of us ever did share.

Good job to you all. Well done!

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Originally Posted by Moparmatty

What is it with this sense of entitlement that everyone has nowadays?

Why does it seem like you all feel that you should be just spoon fed the answers to things? Then you get all huffy when you don't get direct answers.

Why should those of us that have spent countless hours of time figuring out all this stuff, just give up all of our hard earned secrets and tricks for free?

If others are willing to give up their tricks of the trade, that's their prerogative. But forgive me if I think they are crazy.

Just think about something for a minute. Think very hard. When was the last time you saw anyone who's anyone or anyone who actually truly knows anything in the Cummins tuning world make post in here?

I pointed out near the start of this thread that your datalog showed you exactly what has been causing your issue. You just hadn't figured out how to get around the issue. Sure I could have just told you exactly what to change in your tune. But what would you actually learn from that? But because I didn't makes me the bad guy?

It does suck you've been fighting this "issue" for so long. But I find it highly entertaining that one of the people that you just praised so highly, obviously didn't just GIVE you all the answers you sought over curing this "issue" in particular. So why aren't you mad and huffy at him too?

Just remember the next time any of you get pissy because you aren't GIVEN the answer you're looking for. Without a select few us, none of you would even have what you have to tune these trucks. Up until now, of those select few, I was the only one left that does post the odd time in here. You've all successfully ran off anyone that did or may have posted any useful information with your entitlement attitudes and lack of beliefs in the info that anyone of us ever did share.

Good job to you all. Well done!

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Honestly, I wasn't necessarily looking for a direct "spoon fed" answer. I would have been happy with a hint. I understand that you were probably trying to hint at what I was overlooking when you asked what the log showed as the reason for drop in mm3. But when I replied with my response as to what I had attempted under the Allspeed section of the governors and how nothing seemed to have an effect, a helpful, non-spoon feeding response could have been something as simple as, "you're looking in the wrong place". Instead, silence. Which is fine. It certainly is your prerogative to help or not, and I know I'm not owed anything by anyone. It just becomes frustrating (mentally antagonizing) to be led on then left high and dry, is all.

Like I've stated before, it's frustrating to realize that the definitions that HP Tuners has provided for the All Speed RPM limiters are misleading in stating that they are for Manual transmission calibrations, and my truck is an automatic. So I've not played with that limiter with such a deterring definition.

I apologize if I came across as entitled. Certainly wasn't my intention. I stress that my frustration comes from feeling led on, then left high and dry. On top of that, some of your other responses, at least to me, seem a bit condescending. Again, that's just my perception, so forgive me if you weren't intentionally being a bit passive aggressive in your responses.

For the record, I appreciate all those involved that have had a hand in bringing tuning to these trucks more than you know. And I fully understand why some would prefer to keep things to themselves for the benefit of keeping themselves in the "trade secret" business. That being said, in my personal opinion, if that's your stance on the matter, why would you provide even the most cryptic clue to someone figuring out said trade secrets?

I guess my perception of this particular situation was that you must enjoy flaunting the fact that you know more about something than others, and take joy in watching others squirm and struggle with little cryptic hints here and there. Again, please don't take this as an actual accusation, but rather it was my perception of the situation.

Sorry if I've offended you.

I don't tend to post on forums much do to situations like this getting people all fired up. I think we all greatly appreciate all the knowledge and help that more experienced people have to offer and have been providing and I for one hope it continues. A lot of us are trying to understand and learn this as a hobby or after hours activity which slows our advancement time tremendously which maybe why some get vocal. I have been very frustrated at times with trying to over come some of these challenges but by persisting and asking a few questions here and there some very knowledgeable people have been gracious enough to tip me in certain directions. The rest is time and lots of it. That being said I can appreciate the people that have figured things out not giving things away as they put in the time and maybe have a business.

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Originally Posted by B00STJUNKY

Honestly, I wasn't necessarily looking for a direct "spoon fed" answer. I would have been happy with a hint. I understand that you were probably trying to hint at what I was overlooking when you asked what the log showed as the reason for drop in mm3. But when I replied with my response as to what I had attempted under the Allspeed section of the governors and how nothing seemed to have an effect, a helpful, non-spoon feeding response could have been something as simple as, "you're looking in the wrong place". Instead, silence. Which is fine. It certainly is your prerogative to help or not, and I know I'm not owed anything by anyone. It just becomes frustrating (mentally antagonizing) to be led on then left high and dry, is all.

Like I've stated before, it's frustrating to realize that the definitions that HP Tuners has provided for the All Speed RPM limiters are misleading in stating that they are for Manual transmission calibrations, and my truck is an automatic. So I've not played with that limiter with such a deterring definition.

I apologize if I came across as entitled. Certainly wasn't my intention. I stress that my frustration comes from feeling led on, then left high and dry. On top of that, some of your other responses, at least to me, seem a bit condescending. Again, that's just my perception, so forgive me if you weren't intentionally being a bit passive aggressive in your responses.

For the record, I appreciate all those involved that have had a hand in bringing tuning to these trucks more than you know. And I fully understand why some would prefer to keep things to themselves for the benefit of keeping themselves in the "trade secret" business. That being said, in my personal opinion, if that's your stance on the matter, why would you provide even the most cryptic clue to someone figuring out said trade secrets?

I guess my perception of this particular situation was that you must enjoy flaunting the fact that you know more about something than others, and take joy in watching others squirm and struggle with little cryptic hints here and there. Again, please don't take this as an actual accusation, but rather it was my perception of the situation.

Sorry if I've offended you.

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Silence? High and dry?

Because I didn't have or take the time to come back in here and give you any further HINTS before you were GIVEN the answer to your woes by someone else I left you high and dry? Good Lord.

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Originally Posted by Moparmatty

Silence? High and dry?

Because I didn't have or take the time to come back in here and give you any further HINTS before you were GIVEN the answer to your woes by someone else I left you high and dry? Good Lord.

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Again, if my perception of your response and character was incorrect, I apologize. I don't know what more I can do to make you feel less put out by what's transpired here. I know that dragging it out isn't going to help, though.

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It does suck you've been fighting this "issue" for so long. But I find it highly entertaining that one of the people that you just praised so highly, obviously didn't just GIVE you all the answers you sought over curing this "issue" in particular. So why aren't you mad and huffy at him too?

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because the other guy chose to remain silent? I can respect someone choosing to protect intellectual property by not sharing. When you continually choose to antagonize people with your cryptic responses instead of throwing out a nugget of wisdom or at least a nudge in the right direction I have zero respect for you and people of your ilk.

If you are truly as awesome as you think you are I am sure you would be so busy tuning for other people and wouldn't even have the time to troll HPTuners forum.

I have found when I am helpful to the community (I spend most of my time over in the gas burner world) that it pays me back in the long run.

Hey I wrote a post in the Cummins section several weeks ago that didn't even get a response, but it doesn't worry me too much, I'll just keep plugging away. I figured that nobody knows the answer, so they didn't respond!! I know the deal, if someone doesn't want to give away their hard earned knowledge, then that's their right. Don't let it upset you too much. I'm like Dom, bit of a hobby tuner, and I like to help others out if I can

Just as an update, I just finished testing the All Speed RPM limiters being moved up higher than I had them (were set to 5000 before, changed them to 7000), and I am finally getting full commanded fueling, tested up to 4200 RPM thus far. There are now no signs of All Speed clamping down on fueling at that point.

Thank you to those who were gracious enough to give assistance.

Great news. In the end lessons were learned, I think we're all here to learn. Those of us that don't know everything really appreciate everyone sharing here. Before wisdom comes trial and error, before trial and error comes knowledge, in this case knowledge came from reading. Thanks to all.

I want to take a moment to apologize. After re-reading my OP, I can see I didn't provide very much background as to what my (at the time) current understanding level was, nor to what steps I had taken to try an resolve my dilemma up that point. I can easily see how this thread could have been viewed as me looking for spoon-fed information without having put any legwork in for myself based on the limited information I provided here.

It would have been better understood if I had at the very least specified that I fully understood that my limiting factor was the All Speed Governor, and I should have stated all the things I had tried up to that point to overcome said governor (ie. I mentioned having played with Droop settings, which had resulted in a runaway condition, and Decrement Fuel Qty settings, which seemed to have no effect). It would also have been helpful if I had stated that even though I understood that it was the All Speed Governor limiting my fueling, I wasn't sure what it meant when the Master Fuel Correction Reason parameter stated "(Normal)" next to the "All Speed Governor". It made me wonder if I was missing a table somewhere that defined a fuel limitation, and because of that, it would state (Normal) if the fuel curve was simply following what was defined.

I think it provides a little bit of background on what types of things I had already tried or what I had understood nearly 6 months ago when I tried to see if anyone else on this forum had been experiencing similar limitations (link to that thread, here --> http://www.hptuners.com/forum/showth...-mm3-at-4k-RPM)

I have over 40 revisions of my calibration from over the past year that were all related to trying to figure out this fueling limitation. I will also share that I had figured out a workaround and was able to achieve full desired duration by totally rescaling any and all tables and parameters within the calibration that either referenced or defined mm3, simply by multiplying everything by .75, so an original defined mm3 value of 140 would now be 105, or if it was originally defined as 80mm3, it would result in being redefined as 60mm3. This worked to achieve the desired duration, but it decreased overall tuning resolution, and I could notice the truck chugging if I were to snap the APPS momentarily then return to idle condition. The revs would bounce on the way down, so I didn't consider this a good enough solution, and it was back to the drawing board to try and figure out the limiter once and for all so I could have a more smooth running truck.

In short, I feel that I owe Moparmatty an apology. I had it in my head that surely he must have known how much I had already tried to fix my problems, and what my level of understanding was at that point. But I can see based on the context of this thread and the information (or lack thereof) I provided, that he could have never known that. And again, I can easily see why this thread could have been misconstrued as someone looking for a handout more or less. So, Moparmatty, I am sorry for my assumptions. You are probably correct in saying that many of us don't realize how big a part you and others have had in bringing the ability to tune the SCI trucks to the market. But know that I am indeed grateful to all those who were involved. I was on the verge of getting rid of my truck in lieu of getting a newer CAN based truck for the ability to tune via other means. But I'm super grateful that I now have the ability to do so with a tuning device that I already owned and was familiar with.

All that being said, I feel that level-heads, a little bit of humility, and not beating one's chest so as to show how great they envision themselves to be goes a long way in the world of keeping a healthy line of communication vs building up walls. I'm as guilty as the next guy of making these mistakes, and continue to work on improving those areas myself.

Sorry to all who have had to endure unnecessary drama on my account.

It is what it is. People make a living off this stuff and unlike an actual skilled trade, this stuff can be copied and reproduced pretty easily, without having spent the time or earned the knowledge to get you there. I agree that it's very frustrating, but I also agree that now that I know this stuff, I'm not going to post a library of example tunes or information. I'm going to do some tuning and make my money back on my investment of money on this tuning tool and my time to learn how to actually do it. I pick and choose the threads and people that are actually trying, and ask the right way. And I don't go on here very often, because it's rare that I'm going to learn anything.

My background is in a different car community. I was regularly on forums, at shows and meets, and at dyno shops. When I eventually started impacting the local tuning shops and businesses, it became harder and harder to post on forums, my dyno days got blocked and re-scheduled, shops stopped working with me, all because the big boys got butt hurt. So I've learned that providing detailed information and inexpensive quality tunes aren't the best thing to do to make friends in the industry, but I still try to actively participate.

About what you are doing:
Keep an eye on rail pressure. The governor is active like that for a reason. If you go from maxing out the high pressure pump at high rpm, instantly to shutting off the injectors, the rail pressure spike is pretty crazy. I've popped my rail cap several times already on quick shifts at 4000+ on my 2004.5. I guess with an auto it's less of an issue, but it's definately a harsh spike on the whole system if you try to do a car-like fuel cut hard limit up top.

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Originally Posted by Turbo_Mike

It is what it is. People make a living off this stuff and unlike an actual skilled trade, this stuff can be copied and reproduced pretty easily, without having spent the time or earned the knowledge to get you there. I agree that it's very frustrating, but I also agree that now that I know this stuff, I'm not going to post a library of example tunes or information. I'm going to do some tuning and make my money back on my investment of money on this tuning tool and my time to learn how to actually do it. I pick and choose the threads and people that are actually trying, and ask the right way. And I don't go on here very often, because it's rare that I'm going to learn anything.

My background is in a different car community. I was regularly on forums, at shows and meets, and at dyno shops. When I eventually started impacting the local tuning shops and businesses, it became harder and harder to post on forums, my dyno days got blocked and re-scheduled, shops stopped working with me, all because the big boys got butt hurt. So I've learned that providing detailed information and inexpensive quality tunes aren't the best thing to do to make friends in the industry, but I still try to actively participate.

About what you are doing:
Keep an eye on rail pressure. The governor is active like that for a reason. If you go from maxing out the high pressure pump at high rpm, instantly to shutting off the injectors, the rail pressure spike is pretty crazy. I've popped my rail cap several times already on quick shifts at 4000+ on my 2004.5. I guess with an auto it's less of an issue, but it's definately a harsh spike on the whole system if you try to do a car-like fuel cut hard limit up top.

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Very good point in the rail pressure, I'll take a look and see what I can do to address that.

Thanked for your input!

always cut the pump before the injectors, that for the most part will eliminate the issues but being that it's a pid controlled pump it will always have a bit of overshoot when lifting. Just nature of the beast.