A totally different TP application (bin attached)

Noticed that the Mercury marine digital EFI Race boxes used a 28 pin removable chip, so I got a bit curious...

Pulled the attached bin off the chip. 64kb. Scrolling through the 3d Data viewer there are definitely some tables that look like the correct fueling profile for a 2 stroke. This particular ECM used a MAP only, no TPS or any other sensor, other than RPM input. There was also no control of ignition, that was all mechanically controlled by a linkage and trigger.

Anyhow, let me know what you guys can see in this hex file and post up. I have no idea where to start writing an XDF for this because there's no hack, only comments(?) So I am open to any suggestions.

got any idea of what microcontroller is in that box? knowing that, one can start disassembling the BIN.

Quote:

---

Originally Posted by RobertISaar

got any idea of what microcontroller is in that box? knowing that, one can start disassembling the BIN.

---

As far as we know, it's a Motorola 68C11.

pictures/description of the main chip?

after looking at the BIN in a hex editor, it repeats itself right at $8000, so it is actually a 32KB BIN. it has enough vectors at the end of the file to imply to me that it's a standard part, not something like a GM P4 which is its own little brand of different in the world of 6811.

I can look at this more later, I have to leave for a few hours.

Quote:

---

Originally Posted by RobertISaar

pictures/description of the main chip?

after looking at the BIN in a hex editor, it repeats itself right at $8000, so it is actually a 32KB BIN. it has enough vectors at the end of the file to imply to me that it's a standard part, not something like a GM P4 which is its own little brand of different in the world of 6811.

I can look at this more later, I have to leave for a few hours.

---

28 pin UV style chip that I ripped the bin from just like I would from a 27sf512. ECU is a MAP/RPM only marine unit that is used on high performance 2 stroke V6 outboards. There are multiple variations of this ECU that are the same thing with different chips. The bin I posted is from the most desirable A48 version, which is a 9200 RPM limit. Fueling should be mapped out past 11k (a common mod is upping the rev limit to 11,500 so the high compression drag motors aren't on a limiter at half track)



http://i.imgur.com/aA0k0R2.jpg

preliminary info: standard 6811 from what I can tell. has 256 bytes of RAM. most of the PROM is just completely open... code runs from C379 to D48A, a little more than 4000 bytes. calibration seems to run up to 90BF, at most, even then a lot of it looks like filler.

Quote:

---

Originally Posted by RobertISaar

even then a lot of it looks like filler.

---

I imagined it would be, but have no clue what to look for. Not sure if I mentioned it, but the powerhead this was on was 2.5L and has vacuum referenced fuel pressure (up to 39PSI at WOT) Besides the MAP sensor, they have a Temp sensor directly on the head, not sure how it is utilized by the ecm though. I'm interested to get this to the point of tuning, with 250lbs of compression and 112 Sunoco a remap of the fuel curve would be huge.

Would the actual injector flow rates help in any way? I have a set of injectors that have been cleaned up and flowed, I can post the numbers tonight if it would help.

any information would certainly help. if there were any kind of datastream specifications or a rough idea of where the various signals making it into the 6811 go(though with all of that epoxy, I can't see much being easily discerned), that would be helpful too. as-is, I'm guessing at quite a bit at what exactly I'm looking at. going through the power-on reset routine now, nearly at the section where all of the RAM has its values initialized to 0. doesn't look like anything is "learned", though with a marine application, unless it has automatic idle adjustments, not much would need to be. after the RAM is cleared, it does seem to initialize quite a few values to some rough values in batches. it also reclears some values for no apparent reason?

I haven't found any type of checksum function yet. after the initial powerup stuff i'll take a look around for 2D and 3D lookups, should shed some light on some unknown stuff.

Quote:

---

Originally Posted by 1BadAction

28 pin UV style chip that I ripped the bin from just like I would from a 27sf512. ECU is a MAP/RPM only marine unit that is used on high performance 2 stroke V6 outboards. There are multiple variations of this ECU that are the same thing with different chips. The bin I posted is from the most desirable A48 version, which is a 9200 RPM limit. Fueling should be mapped out past 11k (a common mod is upping the rev limit to 11,500 so the high compression drag motors aren't on a limiter at half track)



http://i.imgur.com/aA0k0R2.jpg

---

Could you please tell me what the tube is for?

peace
Hog

Quote:

---

Originally Posted by Hog

Could you please tell me what the tube is for?

peace
Hog

---

I was guessing integrated MAP? I'm curious of the blue square switch in the middle, optional fuel or spark tables?

i couldn't tell if that was a hex switch or a trim pot.... either could have some effect on fuel/spark, but I'm not nearly far enough into the code to say for certain.

can almost make out the crystal frequency from that pic, but not quite.... that information would be good to figure out some of these timing calcs.

Quote:

---

Originally Posted by Hog

Could you please tell me what the tube is for?

peace
Hog

---

Map sensor. Everything is internal to these, the tygon tube exits the aluminum case through a rubber sealed opening and attaches to the Plenum.

Quote:

---

Originally Posted by brian617

I'm curious of the blue square switch in the middle, optional fuel or spark tables?

---

The trim pot will adjust the whole fuel curve plus or minus 10% from the base table. When you go higher compression or cut the intake to get more air in the motor, the only way you can adjust them is by richening up the entire curve until it's not lean when wide open... which is fine at WOT but tends to make the motor slobbery at part throttle and idle.

Here's the injector cleaning sheet. They were tested at 56PSI and the numbers listed are cc/min.

http://i.imgur.com/mjALDDq.jpg?1

http://i.imgur.com/c28vGN2.jpg

i have a decent amount of code figured out at the moment.... but there is some really weird stuff going on with this code, i'll have some very basic stuff figured out pretty quickly, but a lot of this feels really clunky compared to what GM did.

Quote:

---

Originally Posted by RobertISaar

a lot of this feels really clunky compared to what GM did.

---

Yea, I can see that falls right in line with what it was. Limited scope and limited production, most likely done on a small budget, and extremely simple application.

I have an earlier analog box (1985/86 vintage) and the board looks like something someone made in their garage with parts stolen from a tandy and etching solution. LMAO. In a future project I'm going to use the waterproof aluminum case to house a MS3 Pro board and do full sequential injection and ECM controlled ignition.

Quote:

---

Yea, I can see that falls right in line with what it was. Limited scope and limited production, most likely done on a small budget, and extremely simple application.

---

So if you identify tables, develop custom code, you'll likely own the market for tuning this thing.

Quote:

---

Originally Posted by 1project2many

So if you identify tables, develop custom code, you'll likely own the market for tuning this thing.

---

Way too easy to turn 2 strokes into paperweights. If I can adjust fueling tables for my own engines and injector offsets to be able to get away from the stock $200 each injectors I'll be extremely happy.

If/when we figure out anything definitive, I planned on posting a link back to what we find here and info on tunerpro/autoprom on our tech forum @ www.extremeperformanceoutboards.com - we already have a guy running motec and another that's pretty good with megasquirt who are posting information, a way to tune the stock box would be a great addition. The stock box option is the cheapest and simplest by far, doesn't require custom harnesses or changing fuel, charging, and ignition systems. Not going to turn the information loose until I have a chance to test it myself though.

seeing how this appears to be just a standard part.... it wouldn't be too difficult to scrap most of the code and start with something fresh for far better control. just have to get the I/O figured out first. if everything weren't encased in epoxy, it could be done without ever diving into the code.

Quote:

---

Originally Posted by RobertISaar

if everything weren't encased in epoxy, it could be done without ever diving into the code.

---

I'm working on getting a view from the reverse side for you (possibly this evening), and an ECM with cooked injector drivers is ready to come to me, just hasn't been sent yet since it's coming with a couple motors in a crate.

I've de-potted shit before and if I need to I'll do it with this broken one.