"Chipping" a CIS ECU - Page 4 - PeachParts Mercedes-Benz Forum

SpartanV · #46 02-09-2020, 04:12 AM

Haha right on. Did the same thing when adding a resistor to the aux fan temp sensor on the m103 head to engage the fans at a lower temp.

Was wondering if you got fancy and found those 3-way female to male pin Benz clips to make it a plug in play type thing. I think those type of clips can be found in the interior passenger floor area of w124s... The official MB harness for testing the EHA uses a similar type clip but last I checked those harnesses are $80~ thereabouts lol. Now that I think of it I guess this would only work with 2-pin connectors and not the 3 pin pot clip, but shoving the wire in works just as well

Got your PM about the Arduino monitoring. I def want to add this type info display, would be super neat. Still like the idea of your fan controller as well.

duxthe1 · #47 02-09-2020, 10:46 AM

My day job is fixing Benz's, so I have access to pretty much anything MB. The display was never meant to be a permanent thing, so little / no effort beyond the minimum that worked.

I have toyed with the idea of building a LCD / OLED instrument cluster.

Oh, I also wrote a bit of code that reads and calculates RPM from the tach line. Hit me up when you're ready to try it in your own project.

Meanwhile another 15" of snowfall over the past 48hrs has the coupe sidelined for the foreseeable future.

V12 · #48 02-19-2020, 01:19 AM

Good job hacking, this should turn into an fully tunable system.
How about using 29C256 instead of the UV antiques, so you can erase them instantly on the programmer?

duxthe1 · #49 02-19-2020, 08:19 PM

Thanks. Fully tunable is the goal but she isn't giving it up easy. As far as using an eeprom, I honestly hadn't even considered it. If I wear out /break the current batch of chips I may look into it.

I've managed the drive the coupe twice since the last post. Got a new pair of fuel pumps installed because they were starting to get rather noisey on warm days. I also got a Wideband D2 gauge installed. I used the stock location and am using the narrowband simulated output in place of the original narrowband sensor. Initial results aren't very encouraging. It reads about 1 to 1.5 points AFR richer at idle and low load than the actual AFR. This skews the simulated narrowband output making the CIS pull as much fuel as it can, to the point that idle quality gets pretty poor. At WOT and high load it does read in the expected range. This is pretty screwy behavior and I have a couple of possible ideas. Sensor calibration, cheapo controller, or problem with the OE location. Assuming a calibration doesn't improve it, I'll just end up welding in another bung and putting the OE narrowband back in. The wideband reads ok at WOT and that's what I'm actually trying to tune.

duxthe1 · #50 02-23-2020, 08:36 PM

Over the past week, I've figured out the issue using the wideband's narrowband simulation as the O2 input to the CIS. It didn't resolve the wideband reading poorly as a wideband issue though. I'm gonna pull it back out tomorrow and get the narrowband re-installed.

Secondly, new user V12 pointed me towards TunerPro, and specifically the definition file somebody previously built for a close relative KE Jetronic module. TunerPro is a freeware ECU hacking/tuning software and finding that somebody had already defined warmup, load enrichment, WOT trim, idle, and lambda target tables felt like hitting the jackpot. As it turns out, these definitions maybe aren't as advertised. At least to the point of modifying them and burning a chip doesn't produce the immediate results expected. Closer inspection showed some tables were defined without encompassing the entire data set of a given table. At least its a starting point.

Glass half full, the TunerPro software allows you to easily define tables from the bin file and graphicly display them as 2d or 3d tables with the ability to easily modify each datapoint in the tables. So in addition to the 5 tables previously defined, I have located and defined 7 additional tables, which as of yet the functions remain unknown. Well... one of the 7 is a redefining what was initially defined as the idle table. From the original 12 bytes of the idle table, I found it to be part of a larger 52 byte data set.

Going from the brute force method of hacking to using TunerPro is like going from a Festiva to a Ferrari. After getting the narrowbad re-installed I'm going to start modifying these tables and hopefully begin to assign their functions. That fully tunable target feels a bit more possible now.

V12 · #51 02-23-2020, 09:33 PM

Never had much success with those narrowband emulators myself.
I will start working on my CIS soon so we can work on a good definintion for tunerpro here
If only I could actually post here freely..

duxthe1 · #52 02-24-2020, 08:21 PM

Just a quick update. Today I did a little testing and I managed to rename one of the previously defined tables in the .xdf V12 originally linked me to. My definition file will now include a table: "MAP based acceleration enrichment v/s coolant temp" While this is only a 10 byte 2D map, modifying it's values produced noticeable changes in the MAP based enrichment. In its stock form it has the left most value zeroed out, but I don't see a reason why a warm engine wouldn't like a little shot of AE on throttle stabs.

V12 · #53 02-24-2020, 08:29 PM

Great find!
That should make it significantly more responsive, especially for those versions locked at Lambda 1

SpartanV · #54 02-25-2020, 02:47 AM

Additional MAP based enrichment with the hacked "stock" ECU? Cool!

duxthe1 · #55 02-25-2020, 09:05 PM

Yes Sir! I added 35h to the fully warm column for today and on a warm engine it appeared to give 10-15ma on a throttle stab from idle. My engine really liked it and one of my biggest grievances with my stock management was the throttle stab bog. I'd say it was 30% of the reason I took up the endeavor to begin with.

I'm not sure how this would work out on a 103 engine. The 104.980 gets MAP over CAN from the EZL and I'm not sure the 103 does this... Maybe breaking the idle contact on the throttle. Will need a 103 tester at some point.

SpartanV · #56 02-26-2020, 04:39 AM

I'd be down to send an extra m103 ECU to you if you're willing to mess with it

Motor is the 3.0 m103.983 in my 190e...

I know the EZL reads vacuum on the m103 manifold, I figured this was manifold pressure, but not sure it's the same as a modern MAP type sensor? or even later CIS type m104.980 ECU.

Can you elaborate on the throttle stab bog? I always thought the 3.0 was fairly responsive on stabbing the throttle when at speed 55 to 65 mph in 4th or especially 3rd gear, albeit at least when not hitting the WOT switch.

Head is in the shop right now for a basic refresh n valve grind but hoping it will be back by end of next week.

duxthe1 · #57 02-26-2020, 09:59 PM

The EZL does have a MAP sensor, and its the main load input for the ignition map. The 104.980 actually has CAN communication with the EZL and MAP gets bussed over to the CIS.

The 104.980 is infamous for awful throttle response off idle. In stock form while running the AC they wont pull off from a stop until they kick down into 1st gear. As you get up in RPM a bit, they're fine, but if you punch it at idle they tend to bog pretty bad.

duxthe1 · #58 03-05-2020, 09:35 PM

Been working in TunerPro to develop my definition file for this CIS ECU. I've been having a modicum of success. So far I have warmup enrichment, afterstart enrichment, load based accel enrichment, and WOT enrichment. None of which align with the definition file I started from.

I've found that once I have a table defined, zero-ing it out helps see the effects of other tables. Partially adding a table back helps define its axis. The recent warmer weather has the coupe reaching full operating temp and I've noticed the load based accel enrichment cuts off after 87 degrees C. I also noticed what little WOT was present on a cold engine goes away at operating temp. Until today where I found the table that set a fixed WOT current.... that for the first time was present at operating temp. I don't know if it has something to do with a few of the other tables zeroed out but I have a suspicion. Still early and more testing needs to be done.

Getting more familiar with TunerPro I found a feature called the Graphical Table Finder. It takes the selected bin file and displays its values graphically, and you can scroll from end to end. What this does is allow you to easily see patterns, such as data tables, in an otherwise random stream of numbers. Check out the attached pic to see how a table appears from the random noise. Since trying it out for the first time yesterday, I've added several undefined tables to my .XDF file.

V12 · #59 03-06-2020, 12:01 AM

Nice progress !
2d is the best way to identify maps.

I have yet to start messing with mine, since it is the 2x soldered plcc version

duxthe1 · #60 03-06-2020, 08:36 PM

Today I spent the day's driving testing out some modifications to the tables I've defined. Much success! The WOT enrichment table seems to be working as expected and appears to be capable of adding approximately 12mA of positive EHA current. This is at full operating temp, during warmup there is an additional modifier adding more current. The best performing tune today started at 5mA and ramped to 12mA by 7k RPM. I feel like there's still room for improvement in the lower rev range but its noticeably better across the board. Pretty stoked about today's progress, it was nice to be tuning and not exploring for a change.

I have a couple of subroutines I've written that I'm going to add back into the code to change some of the analog reads and also prevent adaptation from working against the extra fueling. Closed loop still works though and normal putzing around is pretty much unchanged.

I'm hesitant to call this success and be done, but it does feel really good having the car run like its pissed off after all the work put into it. Maybe its entering the "fine tuning" stage. I still also want to raise the hot idle speed. I've been trying but no luck so far. Several changes seemed to lower idle speed for whatever reason, but nothing so far has raised it.