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Discussion Starter · #1 · (Edited)
UPDATE

It's been a long haul and while there is still more work to do to get this tune perfect, it has reached the point where it can be made publicly available.

Jan 31, 2023 this tune will be available for purchase. Please PM me for details.

Original Post follows:

This post will end in mostly a question, but first a story that leads up to that question.

My wife and I bought a 2019 Pro4X brand new at the beginning of 2020. Last month I finally had the spare funds to delete and tune my Titan. I put a 0hp tune on the truck because my goal is fuel economy. By tank calculation I'm seeing the fuel economy has improved from 13.6L/100km to 12.5L/100km. The indicated L/100 has not dipped below 9.9L/100km since removed the dpf, but my best indicated economy was 8.7L/100km with the emissions still intact.

One day I had to leave home while the truck was completely cold after removing the dpf and noticed the turbos hunting really badly, ended up making the engine rpm hunt as well. I hooked the ez lynk back up to the truck and started data logging. 4 psig drive pressure, 1.1psig boost at idle. Peak drive pressure of 61psig. Can see the turbos hunt and in general the ecu seems to be holding boost and excessive drive pressure, and has too much gain on the reaction to throttle position.

My best guess is that they didn't adjust the turbo maps to accommodate the reduction of backpressure and that the egr system no longer needs to see the exhaust pressure above the charge pressure. This is leaving a lot of fuel economy on the table.

The tuner offered to reduce the drive pressure for me. However I have been around engines, hot rodding, etc since I was a small child. I can see how I want the maps to be shaped for the turbos. The problem is I need to play with it and make small adjustments until it's perfect. For my driving conditions I'm convinced I can get the hand calculated average down to 9L/100km. No tuner, no matter how polite is going to want to deal with me asking for small changes everyday for the next three months.

So I thought, okay, I'll register as a technician with ez lynk, they have a calibration profile in their ecu editor, it'll be super simple... play with the map, get it perfect... figure out how to block the codes for the dpf delete... Not so simple. I needed a bin. So, I bought the xcal from Nissan for my ecu part number. Dumped it into ez lynk, the data was all disorganized and clearly something was very wrong with it. I thought okay, maybe I need to convert the intel hex to binary, so I wrote an application that did just that. Ez lynk ecu editor did not recognize that as a valid bin.

Now I've opened up the can of worms known as WinOLS... WinOLS recognized both the xcal and my bin. Great, but it's the demo version so I can't export the bin to see if I send it to the truck via ez lynk... After looking at the cost for a WinOLS license, checksum license and the cost for the davos files for the ISV5.0 I'm starting to understand why tuners are so secretive.

Now my question: If I were to pay all the license fees, forum seller fees, successfully write a tune that gave an average of 9-10L/100km (24-26usmpg) mixed driving, 0 hp/0 tq. increase, gave some additional exhaust braking, and also caused throttle response to more closely resemble a 6.0L psd. Would anyone be willing to pay $200usd for 4 weeks or $300usd for permanent support on ez lynk? This would only ever be a 0/0 tune, I would never release anything I wouldn't run on my own engine and I will not turn up my truck.
 

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Discussion Starter · #4 ·
Where did you learn to tune/ get rid of codes like that? Learning how to do that myself would save me a lot of money on my other car.
I’m in the process of figuring it out… :S

I’m one of those people that can do anything they put their mind to… I haven’t succeeded yet mind you.
 

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Discussion Starter · #9 ·
Most of the a2l on the market are not complete. I have the values for codes as well.
The one I looked at they wanted $400usd.

My primary concern is getting the truck to stop coding then I can keep tweaking the turbos until I’m happy. The drive pressure is just insane on this engine.
 

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Discussion Starter · #10 ·
On my 7th revision now. Drive pressure is still 2:1 but I’m starting to realize better than 20% fuel efficiency increase.

An interesting artifact is how much more civilized the transmission is with my tune so far.
 

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Discussion Starter · #11 ·
Stuck on my 9th revision now. Still can't get below 2:1 on the drive pressure. Pretty commonly seeing indicated fuel economy in the 10.2-11.7L/100km range for regular driving. I've been moving enough weight with the truck it's skewing my tank averages so I can't use them as data points right now.

I did try a new bin I got but after installing it, the truck threw a ton of codes that scared me... no way I was going to try starting my truck when it said all the injectors were shorted out. Reinstalled revision 9.

The actual delete part is turning out to be very difficult. The ez lynk editor also does not have access to all the turbo parameters so one of the really important turbine maps I need, I can't access with ez lynk. I've now got winols, but that has a learning curve of its own. The big issue for me right now is having to retune the truck every 400 km (2 days!) to avoid the 8km/h imposed speed limit for non-functioning scr.
 

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Discussion Starter · #13 ·
I suppose this has turned into a journal of sorts. I have worked on the bin for quite a while, compared maps, moved mapped addresses to where it seemed to make sense. I’m very nervous, but tomorrow I will attempt to install this heavily modified bin.

The base concept: Disable all aftertreatment. Disable all alternate emissions modes. Force a specific engine mode that correctly calculates the airflow without egr functioning. Only some very minor tweeks to previous turbo and turbine maps. Main goal is to get it to stop coding but I might as well keep testing my current turbo tune.
 

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Discussion Starter · #14 ·
I was so close to trying my delete tune today... but due to the a2l I got being wrong, and it having to be remapped to the bin that works, it's turned into a massive job. Good thing I double checked my work though, I missed a couple of places where the maps were off and it changed some of the fuel maps and not for the better.

I'll have to keep driving with the cel and the def inducement active until I get my delete issues sorted out.
 

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Discussion Starter · #15 ·
Last night - Today:

I decided to try and take smaller bites out of this. So I tackled the SCR delete, and the driver inducement that it triggers. Installed and the truck started and drove which is nice. The DEF system failure driver inducement is still active though. So I have to keep digging on that front.

Another couple of small tweeks to my turbo map. Smoothed out my boost request for 0 fuel @ 2500-4000 rpm, this is there for engine braking. The turbine bypass valve was set to be fully closed at 0 rpm, changed that value. Now there is only the restriction of the high pressure turbine housing on start up. If there wasn't all the parameters that need to be checked off on start up, it would probably start like my 5.9L did, half a rotation. Once it gives the engine fuel it starts with no hesitation. That was something that bothered me about the truck stock and with the delete tune I was using. The engine would crank and occasionally sputter to life. Looking at how constricted the exhaust path would be on start up, it makes sense now.

I'm really starting to think that the high pressure turbo is designed to have high drive pressure. I'm still a bit hesitant to open the turbine by pass valve to the low pressure turbo at such low engine speeds. If the high pressure turbo needs that drive pressure to work and it's not just a result of the geometry... then it may be a complete dog. That said, even having the high pressure turbine fully exposed works wonders for turbine noise in the exhaust and throttle response is not as badly effected as I originally thought.
 

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Discussion Starter · #18 ·
I got a reply from the sales department for this forum. They do not have any discounted advertising, so there isn't a chance I could recover my costs if I had to pay for advertising. As a result I will open-source my work and tools once I'm confident in my tune.

Instead of working on the tune itself right now, I'm writing an application that will parse both bins, compare the maps and try to locate the correct map locations on the bin that works. Right now I've just got it to the point of reading the bin and outputting it to console. I have about 500hrs of c# experience so far, self taught... so this isn't going to be a quick project. My primary goals will be to get it to find addresses for me so I can update the maps in WinOLS for the working bin. As I go along I'll keep adding functionality until I start editing within the app.

I'm really disappointed how much of a walled garden the diesel tuning community is. How much everything is about money. The automotive tuning side by comparison is wide open.
 

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Discussion Starter · #19 ·
Still working on getting the delete to work, while also working on building my parsing tool... and started building an editor app to simplify things for me.

Got 9.4L/100km (25us.mpg) on a trip today. Bunch of things in the trucks favor, mostly flats, didn't get on the throttle too hard, didn't end up past 95km/h(~60mph).
 

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Discussion Starter · #20 ·
Some more updates: I have been successful in removing the scr failure distance limiting. Most of my time has been spent researching and feeding chicken fever (oh my GOODNESS chickes are so cute!)

The more I dig into this, the more I realize that properly disabling the emissions is a massive undertaking that isn't as simple as blocking some codes. The entire behavior of the engine needs to be changed. Huge Huge thanks to Rawze who is helping me understand how the cummins ecu works.

As best as my understanding right now, there are a number of managers. If we take a single combustion event, lets say the engine is doing 1500rpm and is calling for 10mm^3 of fuel, 5psig manifold pressure and 5 degrees (just as an example, not accurate numbers). This base request is passed into the first manager, I'm just guessing here because... still learning, but say it's the Aftertreatment Manager. It looks at a bunch of parameters and adds or subtracts fuel, timing, boost etc as it sees fit. This value is passed through a number of different managers who are independant of each other until it gets to the point of being acted on. After all the managers it acts on the adjusted value: 11.2mm^3, 6.7psig, 7 degrees. That's really simplified and I'm still not fully understanding but:

When the aftertreatment is removed a number of these managers see values that are not consistent with what is in their respective maps. So they make big adjustments to accommodate for this incorrect value. I didn't completely understand what was going on at the time, but the turbocharger hunting and the issues I noticed with boost were related to how these managers work.

This explains why my truck was holding boost at idle after deleting. Two things happen when you open the egr valve, you relieve some of the drive pressure and reduce the required mass air flow from the compressor. With most deletes, you're not relieving the drive pressure and the turbo has to make up the lost mass air-flow from the egr. So the turbos not only work harder, but take more drive pressure to achieve it.

I'm working at this kind of backwards because I don't have access to the Cummins tools and software that allows direct access to the variables. Right now I'm using a map pack that is only partially correct to get a rough idea where the variable is in the binary (raw machine data). So much fun... so much frustration!
 

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Discussion Starter · #22 ·
Progress is slow. I’m spending most of my time learning how the ecu works and organizes data. I’m working on the hope that I might be able to build valid tunes out of factory xcals instead of using a bin file.

The number of parameters in this engine is staggering.
 

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Discussion Starter · #23 ·
Last night, big break through... I was finally able to extract the itn list from the xcal. Next is to organize that, apply the map pack I have to it and then work on extracting the address list for the itns. This processing the xcal/bin is taking so much longer than trying to figure out the delete itself. Why couldn't I just be happy with badly overdriven turbos and a bunch of code blocking?!
 

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Discussion Starter · #25 ·
Bit of a bigger update:

I'm on the third major rewrite of my editor. The problem:

I have one bin that actually works with the ez lynk autoagent 2.0 and the truck runs on it. This bin also was made from an original calibration as it has no vehicle details, recorded kilometers or whatever.

The WinOLS mappack I bought for the ISV comes with a bin, but it's a slightly different arrangement that produces a long list of errors. It's also interesting to note, that the bin that comes with the WinOLS map pack has mileage on it, which means it was taken from an ecu in a truck. 97,000km(mi?)

Initially I applied the map to the bin that works, but I believe I've mentioned it before, the maps do not perfectly line up. A number of parameters could be found manually, looking for a number of similar bytes in a line. That was not the case for all of them, especially the fault blocking table.

Now I am working off a new Nissan/Cummins .XCAL for my ecu part number. Ideally it will be possible to modify and support every ecu part number with a modifed xcal. I will need to do some more testing but it might also be possible to install the modified file with Nissan Consult.

I exported the WinOLS map pack to json because it has all the correct itn numbers for each parameter. My application can now read the table of contents and the address of every one of those itn's. The next big part will be assigning each map to each itn from the table of contents. Then extracting the data for each itn. That's where it starts getting murcky, as the conversions are not perfectly clear to me for the different data types that are stored in the ecm.

Once I can get the data out, I can document the engine and then learn the best way to modify the program. Another road block is that the winols map pack is aligned to one bin, with everything mapped to the locations in that bin and doesn't use the table of contents. As a result I don't have all of the itns for the axis data because the axis data is hard coded into the winols map pack.

This is both a ton of fun and absolutely frustrating, but I'm getting there.

I talked with ez lynk support and once I have some xcals I'm ready to try, they'll help me make sure they're setup right.
 

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Discussion Starter · #27 ·
Hand calculated tank average, 10.97L/100km (~21us.mpg). Stock wheel/tire sizes, mixed driving but 50% or more on highway. I am constantly driving with an aim towards economy, but not hypermilling. I run with hvac off, but vent on so the ac compressor is not being cycled. The ac compressor uses ~1L/100km.

I'm having issues with extracting the different data points from the xcal, plus the realities of life has slowed this project down a bit. This engine certainly has the potential to be very efficient.
 

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Discussion Starter · #28 ·
Today I successfully extracted 1,2 and 4 byte single datapoints from itns I have information for! Due to the way winols handles maps, all the axis data does not directly correspond. That’s going to be a pretty major uphill battle to extract tables.

I can see light at the end of the tunnel. I will eventually be able to make a profile editor for the ez lynk ecu editor, as well as directly editing thr xcal like I’m doing in my app so far.
 

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Discussion Starter · #30 ·
I keep taking random parameters and comparing the results between the winols demo version I have, a hexeditor with the original xcal open and the results of my silly little application. Everything I have personally checked corresponds correctly between all three. Confidence is growing. I guess this part of the project has only been dragging on for two weeks, but the whole project to get better fuel economy extends a bit earlier than when this thread was started.

Something that is really important to me is somehow sharing this knowledge. We have rare trucks that are not made anymore, a unique engine that isn't made anymore and keeping knowledge like this behind a paywall seems wrong.

Any questions or suggestions on how to share this knowledge so others can use it would be greatly appreciated.

snippet from my git log!
Code:
e678369 2 minutes ago NavyCuda (HEAD -> master, origin/master) OPEN     Continuing work on extracting data from XCal
fb04abf   2 days ago NavyCuda OPEN      Working on data type conversions...
c3edfc5   2 days ago NavyCuda YAY!      Major breakthrough.  Collecting some data from xcal
78cb731   4 days ago NavyCuda Fixed     Table of Contents array indexing issue
6460629   4 days ago NavyCuda OPEN      Major advancements.  Search, and write methods added
fa25702   6 days ago NavyCuda OPEN      Working on search methods.  Verified basic cursor function
13e9a40   8 days ago NavyCuda OPEN      Working on implimenting the new cursor.
96a582d   9 days ago NavyCuda OPEN      Major rewrite...
64d7d7a   9 days ago NavyCuda OPEN      Added loading progress percent.  Started finding values
7fd8045  10 days ago NavyCuda OPEN      Got comments working, now working on getting values
83e523d  10 days ago NavyCuda OPEN      Major changes to how the itns and the index table interact
a26c129  10 days ago NavyCuda OPEN      Working on Documenting the engine.
e3abf3f  12 days ago NavyCuda Starting to pull apart the WinOLS map pack.  Some difficulties
2bff812  12 days ago NavyCuda YAY!      Itn table and addresses successfully extracted
feb96df  13 days ago NavyCuda Got up to about where I was before...
aa128ed  13 days ago NavyCuda Got everything in place.  some issues with git ignore, but that will clear up.
592e60f  13 days ago NavyCuda Set all the projects up
 

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Discussion Starter · #31 ·
Today, successfully have compiled a large list of itns from a number of ecfgs. I can't put any more time into it today, but this should really get me closer to filling out all of the missing itns from the xcal. There are ~19,000 parameters for the ISV, and my list is sitting at about 76,000 parameters, so I'm hoping I can get almost everything filled out nicely. I certainly have found the majority of the axis data I was missing.
 
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