Jeep SBEC PCM tuning (91-95)

Successfully programmed first 64 bytes of a factory ecu. Comms timing issue kept it from continuing.. stupid me had code to erase the loaded room image.. took that out and it started working properly...wooo... Getting closer to the fun part (actual tuning app & 2bar cal)
 
Success!!! ST flash ecus are fully reprogrammable now with interface and tool.

works.jpg


Left hex editor shows erased ecu dump, upper right is ROM to be uploaded, lower right is dump of programmed ecu dump.

Finally after many many hours of development, stock ecus from 95 can be programmed without opening them up. (No potting to deal with, no soldering, just plug the interface in and reprogram)

Now to move onto the fun stuff, PCB design & assembly, production, calibration editing & firmware change software.. one HUGE step closer. Other ecus can be modified to be programmable, some require a little modification, others significant modification.
 
Well I've got the beginnings of an editor for fuel/spark. Need to add code to
*verify & save changes
*injector latency editing for injector swaps *integrate the programming software and upgrade it to Windows instead of command line
*pulse width rescale for inj flow rate changes
*Overview graph for fuel/spark
*Log view & overlay on a graph
*Real time log & display on graph in real time (mostly useful on a Dyno)
*Possibly make it wireless from PC to interface
*Possibly add sd card for real time logs without laptop, so if you have a issue you could go back in the log and review without needing to carry the computer all the time.

When I design the PCB, I'm going to get some produced, but I would like to get an interest count so I know how many I should build once the board is designed & tested. The interface can be upgraded from the computer to add features or correct bugs. Target price of about $150-$300 depending on how much features I add and it will activate the edit/program software. My hardware will be exclusive for use standalone or with my software to eliminate any issues caused by people trying to build their own and causing diagnostic issues.

Here's a editor pic.. just getting started on it.. older picture of the editor, but looks the same so far but added menus and file load, save, etc.
IMG_20180328_233357678.jpg
 
Did some testing on A_Kelly's flashing interface and confirm it works!! Been a very fun and educational project.

Obviously i am in as well.

A_Kelly, I can update my JeepForum thread about our tuning project and gauge interest there as well!
 
Andrew, one of the most useful features, in my mind, would be disabling the security checks.

I just remembered the junkyard ECU I bought work will lock up after some time because the codes don't match the security module.
 
I am super excited.

I've been playing with Comp CamQuest and its definitely my intake&TB that are killing me. The heads I have are monsters -- they should get 400 hp even with the OEM cam.

I have an M1 intake read to install, so it's just a tune I need and possibly having the TB machined out to 52mm.
 
Ok now that I'm back from travel, I'll be getting back on developing the tuning app more to where it's useable to tune and getting logging and graphing going. Along with wideband analog input for data log thru ecu. Should be able to get at least 50 samples/second of 5 or 6 channels. Probably closer to 100-400sps. Plus I'll roll the program/dump/logging into the tuning app. By far the atmel mod is the fastest, programs & verifies in about 5 seconds. Stock flash takes about 2 minutes but might can speed it up.

More to come as I have time available. This project is not being orphaned like so many others have been for sbec/jtec.. jtec may be a future target.
 
Got a basic graph of tables started.. need to enhance colors and maybe blend the blocks smaller for a better view sooner that's what the computer does when running.. but it's a start.
Sorry it's a picture of a screen, don't have a quick way to get stuff from my computer to my phone. (I do have a way, but it's not quick)
IMG_20180408_011548875_HDR.jpg
 
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Want it. Gimme gimme gimme. I neeeed this.

BTW are you able to disable the security check?

Actually, this all may be turbo-able --- if I can find a replacement generic MAP sensor with a voltage range 0V-5V at 0-2Bar, then I can rewrite all these tables.

Andrew, do you think the PCM does linear interpolation between the points?
 
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The sbec 3d code does perform bilinear interpolation on the data points.

Yes the security kill is able to be disabled. Need to add a config page to allow turning features on and off.

There's just a wee little bit more than just rescaling the tables for boost and finding an appropriate sensor. It needs 1) atmospheric reference, 2) sanity checks on MAP samples changed [refer to point 1], and 3) some more stuff I'm forgetting.

Don't worry, it's in the works. In the mean time hang tight, the tuning software is undergoing rapid alpha development changes. I'll keep this update as it progresses.
 
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Both fuel & timing are 3d tables. All of the us 4.0 Jeep cals have had the tables and most of the functions in the same location, I'm wondering if the v8 stuff is similar to the i6 stuff or if it's very different like the turbo cars are. We will find out. The configuration flags seem to be consistent across platforms, which is a plus. Much software development to be done. Kind of rusty on it, been many many many moons since I played programmer. Need to watch timing close because of the lack of knock sensing, which is another future feature.
 
Is the "auto-learning" adjustment of the fuel also a 3D map? I.e. does the computer calculate the correct adjustment at each cell?

Or does it just add a single percentage factor to all cells?

Is there are way of turning off the auto-learning?
 
GarageBuild said:
Is the "auto-learning" adjustment of the fuel also a 3D map? I.e. does the computer calculate the correct adjustment at each cell?

Or does it just add a single percentage factor to all cells?

Is there are way of turning off the auto-learning?
Click to expand...
I haven't gotten that far into the code yet, but if it is similar to the car code, there are separate fuel adjustments per rpm region but is only active in closed loop. WOT/open loop reverts back to the fueling table with no regard to o2 corrections.. I picked up a 5.2 sbec from a 95 zj and the code is very much different from the 6cyl. I'm willing to bet it is a near copy of the truck 5.2/5.9... don't have enough to go off of yet to decide if that's the case or not. Yes the fuel corrections can be turned off to aid tuning

Side note: installed wiring in my Jeep for programming.. I can reprogram in vehicle just by plugging up.
IMG_20180410_224702856_HDRs.jpg
 
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All this is wayyyyy over my head. But I just thought Id let yall know that Ive been following along and this is some cool stuff. If I wasnt in the prep stages of dropping a carbed AMC360 in my ZJ Id be in line for one of them fancy programmers youre making!
 
a_kelley said:
...there are separate fuel adjustments per rpm region but is only active in closed loop....
Click to expand...


maybe for now it might be best for me just to turn off the open loop mode

run closed loop all the time.

i guess i would loose some power at WOT, but that is better than clogging up everything with carbon -- it is too rich at WOT now.

would you be able to turn off open loop?
 
No you can only turn off closed loop. Well.. mainly closed loop is only used under lighter load conditions, so basically excludes WOT. Usually turn it off to tune, & get base tune close, then turn back on. Yes there will be options for that. I'm just getting started on adding options to the editor and it will likely go through a redesign in the user interface.. I throw stuff together to test and then package it after it's tested out thoroughly.. that's just how I work..
 
Ok, cool.

well I am happy with closed loop mode on all the time -- then I don't need to tune anything -- it becomes fully self-learning and I can just drive until it stabilizes.
 
No not quite, closed loop is only to make minor temporary corrections.. the fueling tables must be tuned properly first. The corrections only apply when you are idling or cruising.. Then it's only limited to +/- 20% or so.. the reason to turn off the trims is do during tuning it's not adjusting the fuel when you're trying to see what's going on.. did that make sense?
 
Yes, I understand. But can I ask Why use it that way?

Currently I only need 20% correction. In fact my Jeep passes emissions tests fine so the fuel ratio must be ok.

If I can only turn off the open-loop mode that would be a good improvement.

Currently when I put my foot flat I get smoke, and all the carbon is probably making the internals dirty.

I cant really see myself spending expensive hours on a Dyno getting the tables perfect. So a first priority is to fix this problem.

If I am going to adjust the tables I will probably just reduce all cells by 15%.

BTW I have never tuned a car before.
 
Ok, yeah, you don't need a Dyno to get your tune close. It can be done on the street with a datalog and simply change the values to where it runs at the desired afr. The correction is not used at WOT because the ecu calculates it on the fly, which takes a revolution or two to complete the calculation without trim included. However, in order to properly tune you will need a wideband o2 sensor.. I'm looking into the Spartan system with analog output since I can use the existing o2 input for the wideband and internally convert to narrow band for the existing code while being able to log wideband data.

Another feature that will be added in is an auto tune feature, where you feed the program a data log and desired afr table and it will adjust the tables to try to achieve the desired afr. So no you won't have to be a computer expert or have a Dyno to get a decent tune that's good enough for street driving.

Don't worry, there will be comprehensive documentation on how to tune your computer.. though I will also be able to do tuning over the internet with this software when it's ready to launch.
 
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